rebase: update kubernetes and libraries to v1.22.0 version

Kubernetes v1.22 version has been released and this update
ceph csi dependencies to use the same version.

Signed-off-by: Humble Chirammal <hchiramm@redhat.com>

vendor/go.opentelemetry.io/otel/.gitignore

@@ -0,0 +1,19 @@
+.DS_Store
+Thumbs.db
+
+.tools/
+.idea/
+.vscode/
+*.iml
+*.so
+coverage.*
+
+gen/
+
+/example/jaeger/jaeger
+/example/namedtracer/namedtracer
+/example/opencensus/opencensus
+/example/prometheus/prometheus
+/example/prom-collector/prom-collector
+/example/zipkin/zipkin
+/example/otel-collector/otel-collector

vendor/go.opentelemetry.io/otel/.gitmodules

@@ -0,0 +1,3 @@
+[submodule "opentelemetry-proto"]
+	path = exporters/otlp/internal/opentelemetry-proto
+	url = https://github.com/open-telemetry/opentelemetry-proto

vendor/go.opentelemetry.io/otel/.golangci.yml

@@ -0,0 +1,32 @@
+# See https://github.com/golangci/golangci-lint#config-file
+run:
+  issues-exit-code: 1 #Default
+  tests: true #Default
+
+linters:
+  enable:
+    - misspell
+    - goimports
+    - golint
+    - gofmt
+
+issues:
+  exclude-rules:
+    # helpers in tests often (rightfully) pass a *testing.T as their first argument
+    - path: _test\.go
+      text: "context.Context should be the first parameter of a function"
+      linters:
+        - golint
+    # Yes, they are, but it's okay in a test
+    - path: _test\.go
+      text: "exported func.*returns unexported type.*which can be annoying to use"
+      linters:
+        - golint
+
+linters-settings:
+  misspell:
+    locale: US
+    ignore-words:
+      - cancelled
+  goimports:
+    local-prefixes: go.opentelemetry.io

vendor/go.opentelemetry.io/otel/CODEOWNERS

@@ -0,0 +1,17 @@
+#####################################################
+#
+# List of approvers for this repository
+#
+#####################################################
+#
+# Learn about membership in OpenTelemetry community:
+#  https://github.com/open-telemetry/community/blob/main/community-membership.md
+#
+#
+# Learn about CODEOWNERS file format:
+#  https://help.github.com/en/articles/about-code-owners
+#
+
+* @jmacd @MrAlias @Aneurysm9 @evantorrie @XSAM @dashpole @paivagustavo
+
+CODEOWNERS @MrAlias @Aneurysm9

vendor/go.opentelemetry.io/otel/CONTRIBUTING.md

@@ -0,0 +1,380 @@
+# Contributing to opentelemetry-go
+
+The Go special interest group (SIG) meets regularly. See the
+OpenTelemetry
+[community](https://github.com/open-telemetry/community#golang-sdk)
+repo for information on this and other language SIGs.
+
+See the [public meeting
+notes](https://docs.google.com/document/d/1A63zSWX0x2CyCK_LoNhmQC4rqhLpYXJzXbEPDUQ2n6w/edit#heading=h.9tngw7jdwd6b)
+for a summary description of past meetings. To request edit access,
+join the meeting or get in touch on
+[Slack](https://cloud-native.slack.com/archives/C01NPAXACKT).
+
+## Development
+
+You can view and edit the source code by cloning this repository:
+
+```bash
+git clone https://github.com/open-telemetry/opentelemetry-go.git
+```
+
+Run `make test` to run the tests instead of `go test`. 
+
+There are some generated files checked into the repo. To make sure
+that the generated files are up-to-date, run `make` (or `make
+precommit` - the `precommit` target is the default).
+
+The `precommit` target also fixes the formatting of the code and
+checks the status of the go module files.
+
+If after running `make precommit` the output of `git status` contains
+`nothing to commit, working tree clean` then it means that everything
+is up-to-date and properly formatted.
+
+## Pull Requests
+
+### How to Send Pull Requests
+
+Everyone is welcome to contribute code to `opentelemetry-go` via
+GitHub pull requests (PRs).
+
+To create a new PR, fork the project in GitHub and clone the upstream
+repo:
+
+```sh
+$ go get -d go.opentelemetry.io/otel
+```
+
+(This may print some warning about "build constraints exclude all Go
+files", just ignore it.)
+
+This will put the project in `${GOPATH}/src/go.opentelemetry.io/otel`. You
+can alternatively use `git` directly with:
+
+```sh
+$ git clone https://github.com/open-telemetry/opentelemetry-go
+```
+
+(Note that `git clone` is *not* using the `go.opentelemetry.io/otel` name -
+that name is a kind of a redirector to GitHub that `go get` can
+understand, but `git` does not.)
+
+This would put the project in the `opentelemetry-go` directory in
+current working directory.
+
+Enter the newly created directory and add your fork as a new remote:
+
+```sh
+$ git remote add <YOUR_FORK> git@github.com:<YOUR_GITHUB_USERNAME>/opentelemetry-go
+```
+
+Check out a new branch, make modifications, run linters and tests, update
+`CHANGELOG.md`, and push the branch to your fork:
+
+```sh
+$ git checkout -b <YOUR_BRANCH_NAME>
+# edit files
+# update changelog
+$ make precommit
+$ git add -p
+$ git commit
+$ git push <YOUR_FORK> <YOUR_BRANCH_NAME>
+```
+
+Open a pull request against the main `opentelemetry-go` repo. Be sure to add the pull
+request ID to the entry you added to `CHANGELOG.md`.
+
+### How to Receive Comments
+
+* If the PR is not ready for review, please put `[WIP]` in the title,
+  tag it as `work-in-progress`, or mark it as
+  [`draft`](https://github.blog/2019-02-14-introducing-draft-pull-requests/).
+* Make sure CLA is signed and CI is clear.
+
+### How to Get PRs Merged
+
+A PR is considered to be **ready to merge** when:
+
+* It has received two approvals from Collaborators/Maintainers (at
+  different companies). This is not enforced through technical means
+  and a PR may be **ready to merge** with a single approval if the change
+  and its approach have been discussed and consensus reached.
+* Feedback has been addressed.
+* Any substantive changes to your PR will require that you clear any prior
+  Approval reviews, this includes changes resulting from other feedback. Unless
+  the approver explicitly stated that their approval will persist across
+  changes it should be assumed that the PR needs their review again. Other
+  project members (e.g. approvers, maintainers) can help with this if there are
+  any questions or if you forget to clear reviews.
+* It has been open for review for at least one working day. This gives
+  people reasonable time to review.
+* Trivial changes (typo, cosmetic, doc, etc.) do not have to wait for
+  one day and may be merged with a single Maintainer's approval.
+* `CHANGELOG.md` has been updated to reflect what has been
+  added, changed, removed, or fixed.
+* Urgent fix can take exception as long as it has been actively
+  communicated.
+
+Any Maintainer can merge the PR once it is **ready to merge**.
+
+## Design Choices
+
+As with other OpenTelemetry clients, opentelemetry-go follows the
+[opentelemetry-specification](https://github.com/open-telemetry/opentelemetry-specification).
+
+It's especially valuable to read through the [library
+guidelines](https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/library-guidelines.md).
+
+### Focus on Capabilities, Not Structure Compliance
+
+OpenTelemetry is an evolving specification, one where the desires and
+use cases are clear, but the method to satisfy those uses cases are
+not.
+
+As such, Contributions should provide functionality and behavior that
+conforms to the specification, but the interface and structure is
+flexible.
+
+It is preferable to have contributions follow the idioms of the
+language rather than conform to specific API names or argument
+patterns in the spec.
+
+For a deeper discussion, see:
+https://github.com/open-telemetry/opentelemetry-specification/issues/165
+
+## Style Guide
+
+One of the primary goals of this project is that it is actually used by
+developers. With this goal in mind the project strives to build
+user-friendly and idiomatic Go code adhering to the Go community's best
+practices.
+
+For a non-comprehensive but foundational overview of these best practices
+the [Effective Go](https://golang.org/doc/effective_go.html) documentation
+is an excellent starting place.
+
+As a convenience for developers building this project the `make precommit`
+will format, lint, validate, and in some cases fix the changes you plan to
+submit. This check will need to pass for your changes to be able to be
+merged.
+
+In addition to idiomatic Go, the project has adopted certain standards for
+implementations of common patterns. These standards should be followed as a
+default, and if they are not followed documentation needs to be included as
+to the reasons why.
+
+### Configuration
+
+When creating an instantiation function for a complex `struct` it is useful
+to allow variable number of options to be applied. However, the strong type
+system of Go restricts the function design options. There are a few ways to
+solve this problem, but we have landed on the following design.
+
+#### `config`
+
+Configuration should be held in a `struct` named `config`, or prefixed with
+specific type name this Configuration applies to if there are multiple
+`config` in the package. This `struct` must contain configuration options.
+
+```go
+// config contains configuration options for a thing.
+type config struct {
+    // options ...
+}
+```
+
+In general the `config` `struct` will not need to be used externally to the
+package and should be unexported. If, however, it is expected that the user
+will likely want to build custom options for the configuration, the `config`
+should be exported. Please, include in the documentation for the `config`
+how the user can extend the configuration.
+
+It is important that `config` are not shared across package boundaries.
+Meaning a `config` from one package should not be directly used by another.
+
+Optionally, it is common to include a `newConfig` function (with the same
+naming scheme). This function wraps any defaults setting and looping over
+all options to create a configured `config`.
+
+```go
+// newConfig returns an appropriately configured config.
+func newConfig([]Option) config {
+    // Set default values for config.
+    config := config{/* […] */}
+    for _, option := range options {
+        option.Apply(&config)
+    }
+    // Preform any validation here.
+    return config
+}
+```
+
+If validation of the `config` options is also preformed this can return an
+error as well that is expected to be handled by the instantiation function
+or propagated to the user.
+
+Given the design goal of not having the user need to work with the `config`,
+the `newConfig` function should also be unexported.
+
+#### `Option`
+
+To set the value of the options a `config` contains, a corresponding
+`Option` interface type should be used.
+
+```go
+type Option interface {
+  Apply(*config)
+}
+```
+
+The name of the interface should be prefixed in the same way the
+corresponding `config` is (if at all).
+
+#### Options
+
+All user configurable options for a `config` must have a related unexported
+implementation of the `Option` interface and an exported configuration
+function that wraps this implementation.
+
+The wrapping function name should be prefixed with `With*` (or in the
+special case of a boolean options `Without*`) and should have the following
+function signature.
+
+```go
+func With*(…) Option { … }
+```
+
+##### `bool` Options
+
+```go
+type defaultFalseOption bool
+
+func (o defaultFalseOption) Apply(c *config) {
+    c.Bool = bool(o)
+}
+
+// WithOption sets a T* to have an option included.
+func WithOption() Option {
+    return defaultFalseOption(true)
+}
+```
+
+```go
+type defaultTrueOption bool
+
+func (o defaultTrueOption) Apply(c *config) {
+    c.Bool = bool(o)
+}
+
+// WithoutOption sets a T* to have Bool option excluded.
+func WithoutOption() Option {
+    return defaultTrueOption(false)
+}
+````
+
+##### Declared Type Options
+
+```go
+type myTypeOption struct {
+    MyType MyType
+}
+
+func (o myTypeOption) Apply(c *config) {
+    c.MyType = o.MyType
+}
+
+// WithMyType sets T* to have include MyType.
+func WithMyType(t MyType) Option {
+    return myTypeOption{t}
+}
+```
+
+#### Instantiation
+
+Using this configuration pattern to configure instantiation with a `New*`
+function.
+
+```go
+func NewT*(options ...Option) T* {…}
+```
+
+Any required parameters can be declared before the variadic `options`.
+
+#### Dealing with Overlap
+
+Sometimes there are multiple complex `struct` that share common
+configuration and also have distinct configuration. To avoid repeated
+portions of `config`s, a common `config` can be used with the union of
+options being handled with the `Option` interface.
+
+For example.
+
+```go
+// config holds options for all animals.
+type config struct {
+	Weight      float64
+	Color       string
+	MaxAltitude float64
+}
+
+// DogOption apply Dog specific options.
+type DogOption interface {
+	ApplyDog(*config)
+}
+
+// BirdOption apply Bird specific options.
+type BirdOption interface {
+	ApplyBird(*config)
+}
+
+// Option apply options for all animals.
+type Option interface {
+	BirdOption
+	DogOption
+}
+
+type weightOption float64
+func (o weightOption) ApplyDog(c *config)  { c.Weight = float64(o) }
+func (o weightOption) ApplyBird(c *config) { c.Weight = float64(o) }
+func WithWeight(w float64) Option          { return weightOption(w) }
+
+type furColorOption string
+func (o furColorOption) ApplyDog(c *config) { c.Color = string(o) }
+func WithFurColor(c string) DogOption       { return furColorOption(c) }
+
+type maxAltitudeOption float64
+func (o maxAltitudeOption) ApplyBird(c *config) { c.MaxAltitude = float64(o) }
+func WithMaxAltitude(a float64) BirdOption      { return maxAltitudeOption(a) }
+
+func NewDog(name string, o ...DogOption) Dog    {…}
+func NewBird(name string, o ...BirdOption) Bird {…}
+```
+
+### Interface Type
+
+To allow other developers to better comprehend the code, it is important
+to ensure it is sufficiently documented. One simple measure that contributes
+to this aim is self-documenting by naming method parameters. Therefore,
+where appropriate, methods of every exported interface type should have
+their parameters appropriately named.
+
+## Approvers and Maintainers
+
+Approvers:
+
+- [Evan Torrie](https://github.com/evantorrie), Verizon Media
+- [Josh MacDonald](https://github.com/jmacd), LightStep
+- [Sam Xie](https://github.com/XSAM)
+- [David Ashpole](https://github.com/dashpole), Google
+- [Gustavo Silva Paiva](https://github.com/paivagustavo), LightStep
+
+Maintainers:
+
+- [Anthony Mirabella](https://github.com/Aneurysm9), AWS
+- [Tyler Yahn](https://github.com/MrAlias), Splunk
+
+### Become an Approver or a Maintainer
+
+See the [community membership document in OpenTelemetry community
+repo](https://github.com/open-telemetry/community/blob/main/community-membership.md).

vendor/go.opentelemetry.io/otel/LICENSE

@@ -0,0 +1,201 @@
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
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vendor/go.opentelemetry.io/otel/Makefile

@@ -0,0 +1,179 @@
+# Copyright The OpenTelemetry Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+EXAMPLES := $(shell ./get_main_pkgs.sh ./example)
+TOOLS_MOD_DIR := ./internal/tools
+
+# All source code and documents. Used in spell check.
+ALL_DOCS := $(shell find . -name '*.md' -type f | sort)
+# All directories with go.mod files related to opentelemetry library. Used for building, testing and linting.
+ALL_GO_MOD_DIRS := $(filter-out $(TOOLS_MOD_DIR), $(shell find . -type f -name 'go.mod' -exec dirname {} \; | egrep -v '^./example' | sort)) $(shell find ./example -type f -name 'go.mod' -exec dirname {} \; | sort)
+ALL_COVERAGE_MOD_DIRS := $(shell find . -type f -name 'go.mod' -exec dirname {} \; | egrep -v '^./example|^$(TOOLS_MOD_DIR)' | sort)
+
+GO = go
+TIMEOUT = 60
+
+.DEFAULT_GOAL := precommit
+
+.PHONY: precommit ci
+precommit: dependabot-check license-check lint build examples test-default
+ci: precommit check-clean-work-tree test-coverage
+
+# Tools
+
+TOOLS = $(CURDIR)/.tools
+
+$(TOOLS):
+	@mkdir -p $@
+$(TOOLS)/%: | $(TOOLS)
+	cd $(TOOLS_MOD_DIR) && \
+	$(GO) build -o $@ $(PACKAGE)
+
+CROSSLINK = $(TOOLS)/crosslink
+$(TOOLS)/crosslink: PACKAGE=go.opentelemetry.io/otel/$(TOOLS_MOD_DIR)/crosslink
+
+GOLANGCI_LINT = $(TOOLS)/golangci-lint
+$(TOOLS)/golangci-lint: PACKAGE=github.com/golangci/golangci-lint/cmd/golangci-lint
+
+MISSPELL = $(TOOLS)/misspell
+$(TOOLS)/misspell: PACKAGE= github.com/client9/misspell/cmd/misspell
+
+STRINGER = $(TOOLS)/stringer
+$(TOOLS)/stringer: PACKAGE=golang.org/x/tools/cmd/stringer
+
+$(TOOLS)/gojq: PACKAGE=github.com/itchyny/gojq/cmd/gojq
+
+.PHONY: tools
+tools: $(CROSSLINK) $(GOLANGCI_LINT) $(MISSPELL) $(STRINGER) $(TOOLS)/gojq
+
+
+# Build
+
+.PHONY: examples generate build
+examples:
+	@set -e; for dir in $(EXAMPLES); do \
+	  echo "$(GO) build $${dir}/..."; \
+	  (cd "$${dir}" && \
+	   $(GO) build .); \
+	done
+
+generate: $(STRINGER)
+	set -e; for dir in $(ALL_GO_MOD_DIRS); do \
+	  echo "$(GO) generate $${dir}/..."; \
+	  (cd "$${dir}" && \
+	    PATH="$(TOOLS):$${PATH}" $(GO) generate ./...); \
+	done
+
+build: generate
+	# Build all package code including testing code.
+	set -e; for dir in $(ALL_GO_MOD_DIRS); do \
+	  echo "$(GO) build $${dir}/..."; \
+	  (cd "$${dir}" && \
+	    $(GO) build ./... && \
+		$(GO) list ./... \
+		  | grep -v third_party \
+		  | xargs $(GO) test -vet=off -run xxxxxMatchNothingxxxxx >/dev/null); \
+	done
+
+# Tests
+
+TEST_TARGETS := test-default test-bench test-short test-verbose test-race
+.PHONY: $(TEST_TARGETS) test
+test-default: ARGS=-v -race
+test-bench:   ARGS=-run=xxxxxMatchNothingxxxxx -test.benchtime=1ms -bench=.
+test-short:   ARGS=-short
+test-verbose: ARGS=-v
+test-race:    ARGS=-race
+$(TEST_TARGETS): test
+test:
+	@set -e; for dir in $(ALL_GO_MOD_DIRS); do \
+	  echo "$(GO) test -timeout $(TIMEOUT)s $(ARGS) $${dir}/..."; \
+	  (cd "$${dir}" && \
+	    $(GO) list ./... \
+		  | grep -v third_party \
+		  | xargs $(GO) test -timeout $(TIMEOUT)s $(ARGS)); \
+	done
+
+COVERAGE_MODE    = atomic
+COVERAGE_PROFILE = coverage.out
+.PHONY: test-coverage
+test-coverage:
+	@set -e; \
+	printf "" > coverage.txt; \
+	for dir in $(ALL_COVERAGE_MOD_DIRS); do \
+	  echo "$(GO) test -coverpkg=./... -covermode=$(COVERAGE_MODE) -coverprofile="$(COVERAGE_PROFILE)" $${dir}/..."; \
+	  (cd "$${dir}" && \
+	    $(GO) list ./... \
+	    | grep -v third_party \
+	    | xargs $(GO) test -coverpkg=./... -covermode=$(COVERAGE_MODE) -coverprofile="$(COVERAGE_PROFILE)" && \
+	  $(GO) tool cover -html=coverage.out -o coverage.html); \
+	  [ -f "$${dir}/coverage.out" ] && cat "$${dir}/coverage.out" >> coverage.txt; \
+	done; \
+	sed -i.bak -e '2,$$ { /^mode: /d; }' coverage.txt
+
+.PHONY: lint
+lint: misspell lint-modules | $(GOLANGCI_LINT)
+	set -e; for dir in $(ALL_GO_MOD_DIRS); do \
+	  echo "golangci-lint in $${dir}"; \
+	  (cd "$${dir}" && \
+	    $(GOLANGCI_LINT) run --fix && \
+	    $(GOLANGCI_LINT) run); \
+	done
+
+.PHONY: misspell
+misspell: | $(MISSPELL)
+	$(MISSPELL) -w $(ALL_DOCS)
+
+.PHONY: lint-modules
+lint-modules: | $(CROSSLINK)
+	set -e; for dir in $(ALL_GO_MOD_DIRS) $(TOOLS_MOD_DIR); do \
+	  echo "$(GO) mod tidy in $${dir}"; \
+	  (cd "$${dir}" && \
+	    $(GO) mod tidy); \
+	done
+	echo "cross-linking all go modules"
+	$(CROSSLINK)
+
+.PHONY: license-check
+license-check:
+	@licRes=$$(for f in $$(find . -type f \( -iname '*.go' -o -iname '*.sh' \) ! -path '**/third_party/*' ! -path './exporters/otlp/internal/opentelemetry-proto/*') ; do \
+	           awk '/Copyright The OpenTelemetry Authors|generated|GENERATED/ && NR<=3 { found=1; next } END { if (!found) print FILENAME }' $$f; \
+	   done); \
+	   if [ -n "$${licRes}" ]; then \
+	           echo "license header checking failed:"; echo "$${licRes}"; \
+	           exit 1; \
+	   fi
+
+.PHONY: dependabot-check
+dependabot-check:
+	@result=$$( \
+		for f in $$( find . -type f -name go.mod -exec dirname {} \; | sed 's/^.\/\?/\//' ); \
+			do grep -q "$$f" .github/dependabot.yml \
+			|| echo "$$f"; \
+		done; \
+	); \
+	if [ -n "$$result" ]; then \
+		echo "missing go.mod dependabot check:"; echo "$$result"; \
+		exit 1; \
+	fi
+
+.PHONY: check-clean-work-tree
+check-clean-work-tree:
+	@if ! git diff --quiet; then \
+	  echo; \
+	  echo 'Working tree is not clean, did you forget to run "make precommit"?'; \
+	  echo; \
+	  git status; \
+	  exit 1; \
+	fi

vendor/go.opentelemetry.io/otel/README.md

@@ -0,0 +1,92 @@
+# OpenTelemetry-Go
+
+[![CI](https://github.com/open-telemetry/opentelemetry-go/workflows/ci/badge.svg)](https://github.com/open-telemetry/opentelemetry-go/actions?query=workflow%3Aci+branch%3Amain)
+[![PkgGoDev](https://pkg.go.dev/badge/go.opentelemetry.io/otel)](https://pkg.go.dev/go.opentelemetry.io/otel)
+[![Go Report Card](https://goreportcard.com/badge/go.opentelemetry.io/otel)](https://goreportcard.com/report/go.opentelemetry.io/otel)
+[![Slack](https://img.shields.io/badge/slack-@cncf/otel--go-brightgreen.svg?logo=slack)](https://cloud-native.slack.com/archives/C01NPAXACKT)
+
+
+The Go [OpenTelemetry](https://opentelemetry.io/) implementation.
+
+## Project Status
+
+**Warning**: this project is currently in a pre-GA phase. Backwards
+incompatible changes may be introduced in subsequent minor version releases as
+we work to track the evolving OpenTelemetry specification and user feedback.
+
+Our progress towards a GA release candidate is tracked in [this project
+board](https://github.com/orgs/open-telemetry/projects/5). This release
+candidate will follow semantic versioning and will be released with a major
+version greater than zero.
+
+Progress and status specific to this repository is tracked in our local
+[project boards](https://github.com/open-telemetry/opentelemetry-go/projects)
+and
+[milestones](https://github.com/open-telemetry/opentelemetry-go/milestones).
+
+Project versioning information and stability guarantees can be found in the
+[versioning documentation](./VERSIONING.md).
+
+### Compatibility
+
+This project is tested on the following systems.
+
+| OS      | Go Version | Architecture |
+| ------- | ---------- | ------------ |
+| Ubuntu  | 1.15       | amd64        |
+| Ubuntu  | 1.14       | amd64        |
+| Ubuntu  | 1.15       | 386          |
+| Ubuntu  | 1.14       | 386          |
+| MacOS   | 1.15       | amd64        |
+| MacOS   | 1.14       | amd64        |
+| Windows | 1.15       | amd64        |
+| Windows | 1.14       | amd64        |
+| Windows | 1.15       | 386          |
+| Windows | 1.14       | 386          |
+
+While this project should work for other systems, no compatibility guarantees
+are made for those systems currently.
+
+## Getting Started
+
+You can find a getting started guide on [opentelemetry.io](https://opentelemetry.io/docs/go/getting-started/).
+
+OpenTelemetry's goal is to provide a single set of APIs to capture distributed
+traces and metrics from your application and send them to an observability
+platform. This project allows you to do just that for applications written in
+Go. There are two steps to this process: instrument your application, and
+configure an exporter.
+
+### Instrumentation
+
+To start capturing distributed traces and metric events from your application
+it first needs to be instrumented. The easiest way to do this is by using an
+instrumentation library for your code. Be sure to check out [the officially
+supported instrumentation
+libraries](https://github.com/open-telemetry/opentelemetry-go-contrib/tree/main/instrumentation).
+
+If you need to extend the telemetry an instrumentation library provides or want
+to build your own instrumentation for your application directly you will need
+to use the
+[go.opentelemetry.io/otel/api](https://pkg.go.dev/go.opentelemetry.io/otel/api)
+package. The included [examples](./example/) are a good way to see some
+practical uses of this process.
+
+### Export
+
+Now that your application is instrumented to collect telemetry, it needs an
+export pipeline to send that telemetry to an observability platform.
+
+You can find officially supported exporters [here](./exporters/) and in the
+companion [contrib
+repository](https://github.com/open-telemetry/opentelemetry-go-contrib/tree/main/exporters/metric).
+Additionally, there are many vendor specific or 3rd party exporters for
+OpenTelemetry. These exporters are broken down by
+[trace](https://pkg.go.dev/go.opentelemetry.io/otel/sdk/export/trace?tab=importedby)
+and
+[metric](https://pkg.go.dev/go.opentelemetry.io/otel/sdk/export/metric?tab=importedby)
+support.
+
+## Contributing
+
+See the [contributing documentation](CONTRIBUTING.md).

vendor/go.opentelemetry.io/otel/RELEASING.md

@@ -0,0 +1,81 @@
+# Release Process
+
+## Pre-Release
+
+Update go.mod for submodules to depend on the new release which will happen in the next step.
+
+1. Run the pre-release script. It creates a branch `pre_release_<new tag>` that will contain all release changes.
+
+    ```
+    ./pre_release.sh -t <new tag>
+    ```
+
+2. Verify the changes.
+
+    ```
+    git diff main
+    ```
+
+    This should have changed the version for all modules to be `<new tag>`.
+
+3. Update the [Changelog](./CHANGELOG.md).
+   - Make sure all relevant changes for this release are included and are in language that non-contributors to the project can understand.
+       To verify this, you can look directly at the commits since the `<last tag>`.
+
+       ```
+       git --no-pager log --pretty=oneline "<last tag>..HEAD"
+       ```
+
+   - Move all the `Unreleased` changes into a new section following the title scheme (`[<new tag>] - <date of release>`).
+   - Update all the appropriate links at the bottom.
+
+4. Push the changes to upstream and create a Pull Request on GitHub.
+    Be sure to include the curated changes from the [Changelog](./CHANGELOG.md) in the description.
+
+
+## Tag
+
+Once the Pull Request with all the version changes has been approved and merged it is time to tag the merged commit.
+
+***IMPORTANT***: It is critical you use the same tag that you used in the Pre-Release step!
+Failure to do so will leave things in a broken state.
+
+***IMPORTANT***: [There is currently no way to remove an incorrectly tagged version of a Go module](https://github.com/golang/go/issues/34189).
+It is critical you make sure the version you push upstream is correct.
+[Failure to do so will lead to minor emergencies and tough to work around](https://github.com/open-telemetry/opentelemetry-go/issues/331).
+
+1. Run the tag.sh script using the `<commit-hash>` of the commit on the main branch for the merged Pull Request.
+
+    ```
+    ./tag.sh <new tag> <commit-hash>
+    ```
+
+2. Push tags to the upstream remote (not your fork: `github.com/open-telemetry/opentelemetry-go.git`).
+    Make sure you push all sub-modules as well.
+
+    ```
+    git push upstream <new tag>
+    git push upstream <submodules-path/new tag>
+    ...
+    ```
+
+## Release
+
+Finally create a Release for the new `<new tag>` on GitHub.
+The release body should include all the release notes from the Changelog for this release.
+Additionally, the `tag.sh` script generates commit logs since last release which can be used to supplement the release notes.
+
+## Verify Examples
+
+After releasing verify that examples build outside of the repository.
+
+```
+./verify_examples.sh
+```
+
+The script copies examples into a different directory removes any `replace` declarations in `go.mod` and builds them.
+This ensures they build with the published release, not the local copy.
+
+## Contrib Repository
+
+Once verified be sure to [make a release for the `contrib` repository](https://github.com/open-telemetry/opentelemetry-go-contrib/blob/main/RELEASING.md) that uses this release.

vendor/go.opentelemetry.io/otel/VERSIONING.md

@@ -0,0 +1,217 @@
+# Versioning
+
+This document describes the versioning policy for this repository. This policy
+is designed so the following goals can be achieved.
+
+**Users are provided a codebase of value that is stable and secure.**
+
+## Policy
+
+* Versioning of this project will be idiomatic of a Go project using [Go
+  modules](https://github.com/golang/go/wiki/Modules).
+  * [Semantic import
+    versioning](https://github.com/golang/go/wiki/Modules#semantic-import-versioning)
+    will be used.
+    * Versions will comply with [semver 2.0](https://semver.org/spec/v2.0.0.html).
+    * If a module is version `v2` or higher, the major version of the module
+      must be included as a `/vN` at the end of the module paths used in
+      `go.mod` files (e.g., `module go.opentelemetry.io/otel/v2`, `require
+      go.opentelemetry.io/otel/v2 v2.0.1`) and in the package import path
+      (e.g., `import "go.opentelemetry.io/otel/v2/trace"`). This includes the
+      paths used in `go get` commands (e.g., `go get
+      go.opentelemetry.io/otel/v2@v2.0.1`.  Note there is both a `/v2` and a
+      `@v2.0.1` in that example. One way to think about it is that the module
+      name now includes the `/v2`, so include `/v2` whenever you are using the
+      module name).
+    * If a module is version `v0` or `v1`, do not include the major version in
+      either the module path or the import path.
+  * Modules will be used to encapsulate signals and components.
+    * Experimental modules still under active development will be versioned at
+      `v0` to imply the stability guarantee defined by
+      [semver](https://semver.org/spec/v2.0.0.html#spec-item-4).
+
+      > Major version zero (0.y.z) is for initial development. Anything MAY
+      > change at any time. The public API SHOULD NOT be considered stable.
+
+    * Mature modules for which we guarantee a stable public API will be versioned
+      with a major version greater than `v0`.
+      * The decision to make a module stable will be made on a case-by-case
+        basis by the maintainers of this project.
+    * Experimental modules will start their versioning at `v0.0.0` and will
+      increment their minor version when backwards incompatible changes are
+      released and increment their patch version when backwards compatible
+      changes are released.
+    * All stable modules that use the same major version number will use the
+      same entire version number.
+      * Stable modules may be released with an incremented minor or patch
+        version even though that module has not been changed, but rather so
+        that it will remain at the same version as other stable modules that
+        did undergo change.
+      * When an experimental module becomes stable a new stable module version
+        will be released and will include this now stable module. The new
+        stable module version will be an increment of the minor version number
+        and will be applied to all existing stable modules as well as the newly
+        stable module being released.
+* Versioning of the associated [contrib
+  repository](https://github.com/open-telemetry/opentelemetry-go-contrib) of
+  this project will be idiomatic of a Go project using [Go
+  modules](https://github.com/golang/go/wiki/Modules).
+  * [Semantic import
+    versioning](https://github.com/golang/go/wiki/Modules#semantic-import-versioning)
+    will be used.
+    * Versions will comply with [semver 2.0](https://semver.org/spec/v2.0.0.html).
+    * If a module is version `v2` or higher, the
+      major version of the module must be included as a `/vN` at the end of the
+      module paths used in `go.mod` files (e.g., `module
+      go.opentelemetry.io/contrib/instrumentation/host/v2`, `require
+      go.opentelemetry.io/contrib/instrumentation/host/v2 v2.0.1`) and in the
+      package import path (e.g., `import
+      "go.opentelemetry.io/contrib/instrumentation/host/v2"`). This includes
+      the paths used in `go get` commands (e.g., `go get
+      go.opentelemetry.io/contrib/instrumentation/host/v2@v2.0.1`.  Note there
+      is both a `/v2` and a `@v2.0.1` in that example. One way to think about
+      it is that the module name now includes the `/v2`, so include `/v2`
+      whenever you are using the module name).
+    * If a module is version `v0` or `v1`, do not include the major version
+      in either the module path or the import path.
+  * In addition to public APIs, telemetry produced by stable instrumentation
+    will remain stable and backwards compatible. This is to avoid breaking
+    alerts and dashboard.
+  * Modules will be used to encapsulate instrumentation, detectors, exporters,
+    propagators, and any other independent sets of related components.
+    * Experimental modules still under active development will be versioned at
+      `v0` to imply the stability guarantee defined by
+      [semver](https://semver.org/spec/v2.0.0.html#spec-item-4).
+
+      > Major version zero (0.y.z) is for initial development. Anything MAY
+      > change at any time. The public API SHOULD NOT be considered stable.
+
+    * Mature modules for which we guarantee a stable public API and telemetry will
+      be versioned with a major version greater than `v0`.
+    * Experimental modules will start their versioning at `v0.0.0` and will
+      increment their minor version when backwards incompatible changes are
+      released and increment their patch version when backwards compatible
+      changes are released.
+    * Stable contrib modules cannot depend on experimental modules from this
+      project.
+    * All stable contrib modules of the same major version with this project
+      will use the same entire version as this project.
+      * Stable modules may be released with an incremented minor or patch
+        version even though that module's code has not been changed. Instead
+        the only change that will have been included is to have updated that
+        modules dependency on this project's stable APIs.
+      * When an experimental module in contrib becomes stable a new stable
+        module version will be released and will include this now stable
+        module. The new stable module version will be an increment of the minor
+        version number and will be applied to all existing stable contrib
+        modules, this project's modules, and the newly stable module being
+        released.
+  * Contrib modules will be kept up to date with this project's releases.
+    * Due to the dependency contrib modules will implicitly have on this
+      project's modules the release of stable contrib modules to match the
+      released version number will be staggered after this project's release.
+      There is no explicit time guarantee for how long after this projects
+      release the contrib release will be. Effort should be made to keep them
+      as close in time as possible.
+    * No additional stable release in this project can be made until the
+      contrib repository has a matching stable release.
+    * No release can be made in the contrib repository after this project's
+      stable release except for a stable release of the contrib repository.
+* GitHub releases will be made for all releases.
+* Go modules will be made available at Go package mirrors.
+
+## Example Versioning Lifecycle
+
+To better understand the implementation of the above policy the following
+example is provided. This project is simplified to include only the following
+modules and their versions:
+
+* `otel`: `v0.14.0`
+* `otel/trace`: `v0.14.0`
+* `otel/metric`: `v0.14.0`
+* `otel/baggage`: `v0.14.0`
+* `otel/sdk/trace`: `v0.14.0`
+* `otel/sdk/metric`: `v0.14.0`
+
+These modules have been developed to a point where the `otel/trace`,
+`otel/baggage`, and `otel/sdk/trace` modules have reached a point that they
+should be considered for a stable release. The `otel/metric` and
+`otel/sdk/metric` are still under active development and the `otel` module
+depends on both `otel/trace` and `otel/metric`.
+
+The `otel` package is refactored to remove its dependencies on `otel/metric` so
+it can be released as stable as well. With that done the following release
+candidates are made:
+
+* `otel`: `v1.0.0-rc.1`
+* `otel/trace`: `v1.0.0-rc.1`
+* `otel/baggage`: `v1.0.0-rc.1`
+* `otel/sdk/trace`: `v1.0.0-rc.1`
+
+The `otel/metric` and `otel/sdk/metric` modules remain at `v0.14.0`.
+
+A few minor issues are discovered in the `otel/trace` package. These issues are
+resolved with some minor, but backwards incompatible, changes and are released
+as a second release candidate:
+
+* `otel`: `v1.0.0-rc.2`
+* `otel/trace`: `v1.0.0-rc.2`
+* `otel/baggage`: `v1.0.0-rc.2`
+* `otel/sdk/trace`: `v1.0.0-rc.2`
+
+Notice that all module version numbers are incremented to adhere to our
+versioning policy.
+
+After these release candidates have been evaluated to satisfaction, they are
+released as version `v1.0.0`.
+
+* `otel`: `v1.0.0`
+* `otel/trace`: `v1.0.0`
+* `otel/baggage`: `v1.0.0`
+* `otel/sdk/trace`: `v1.0.0`
+
+Since both the `go` utility and the Go module system support [the semantic
+versioning definition of
+precedence](https://semver.org/spec/v2.0.0.html#spec-item-11), this release
+will correctly be interpreted as the successor to the previous release
+candidates.
+
+Active development of this project continues. The `otel/metric` module now has
+backwards incompatible changes to its API that need to be released and the
+`otel/baggage` module has a minor bug fix that needs to be released. The
+following release is made:
+
+* `otel`: `v1.0.1`
+* `otel/trace`: `v1.0.1`
+* `otel/metric`: `v0.15.0`
+* `otel/baggage`: `v1.0.1`
+* `otel/sdk/trace`: `v1.0.1`
+* `otel/sdk/metric`: `v0.15.0`
+
+Notice that, again, all stable module versions are incremented in unison and
+the `otel/sdk/metric` package, which depends on the `otel/metric` package, also
+bumped its version. This bump of the `otel/sdk/metric` package makes sense
+given their coupling, though it is not explicitly required by our versioning
+policy.
+
+As we progress, the `otel/metric` and `otel/sdk/metric` packages have reached a
+point where they should be evaluated for stability. The `otel` module is
+reintegrated with the `otel/metric` package and the following release is made:
+
+* `otel`: `v1.1.0-rc.1`
+* `otel/trace`: `v1.1.0-rc.1`
+* `otel/metric`: `v1.1.0-rc.1`
+* `otel/baggage`: `v1.1.0-rc.1`
+* `otel/sdk/trace`: `v1.1.0-rc.1`
+* `otel/sdk/metric`: `v1.1.0-rc.1`
+
+All the modules are evaluated and determined to a viable stable release. They
+are then released as version `v1.1.0` (the minor version is incremented to
+indicate the addition of new signal).
+
+* `otel`: `v1.1.0`
+* `otel/trace`: `v1.1.0`
+* `otel/metric`: `v1.1.0`
+* `otel/baggage`: `v1.1.0`
+* `otel/sdk/trace`: `v1.1.0`
+* `otel/sdk/metric`: `v1.1.0`

vendor/go.opentelemetry.io/otel/attribute/doc.go

@@ -0,0 +1,20 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// package attribute provides key and value attributes.
+//
+// This package is currently in a pre-GA phase. Backwards incompatible changes
+// may be introduced in subsequent minor version releases as we work to track
+// the evolving OpenTelemetry specification and user feedback.
+package attribute // import "go.opentelemetry.io/otel/attribute"

vendor/go.opentelemetry.io/otel/attribute/encoder.go

@@ -0,0 +1,150 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package attribute // import "go.opentelemetry.io/otel/attribute"
+
+import (
+	"bytes"
+	"sync"
+	"sync/atomic"
+)
+
+type (
+	// Encoder is a mechanism for serializing a label set into a
+	// specific string representation that supports caching, to
+	// avoid repeated serialization. An example could be an
+	// exporter encoding the label set into a wire representation.
+	Encoder interface {
+		// Encode returns the serialized encoding of the label
+		// set using its Iterator.  This result may be cached
+		// by a attribute.Set.
+		Encode(iterator Iterator) string
+
+		// ID returns a value that is unique for each class of
+		// label encoder.  Label encoders allocate these using
+		// `NewEncoderID`.
+		ID() EncoderID
+	}
+
+	// EncoderID is used to identify distinct Encoder
+	// implementations, for caching encoded results.
+	EncoderID struct {
+		value uint64
+	}
+
+	// defaultLabelEncoder uses a sync.Pool of buffers to reduce
+	// the number of allocations used in encoding labels.  This
+	// implementation encodes a comma-separated list of key=value,
+	// with '/'-escaping of '=', ',', and '\'.
+	defaultLabelEncoder struct {
+		// pool is a pool of labelset builders.  The buffers in this
+		// pool grow to a size that most label encodings will not
+		// allocate new memory.
+		pool sync.Pool // *bytes.Buffer
+	}
+)
+
+// escapeChar is used to ensure uniqueness of the label encoding where
+// keys or values contain either '=' or ','.  Since there is no parser
+// needed for this encoding and its only requirement is to be unique,
+// this choice is arbitrary.  Users will see these in some exporters
+// (e.g., stdout), so the backslash ('\') is used as a conventional choice.
+const escapeChar = '\\'
+
+var (
+	_ Encoder = &defaultLabelEncoder{}
+
+	// encoderIDCounter is for generating IDs for other label
+	// encoders.
+	encoderIDCounter uint64
+
+	defaultEncoderOnce     sync.Once
+	defaultEncoderID       = NewEncoderID()
+	defaultEncoderInstance *defaultLabelEncoder
+)
+
+// NewEncoderID returns a unique label encoder ID. It should be
+// called once per each type of label encoder. Preferably in init() or
+// in var definition.
+func NewEncoderID() EncoderID {
+	return EncoderID{value: atomic.AddUint64(&encoderIDCounter, 1)}
+}
+
+// DefaultEncoder returns a label encoder that encodes labels
+// in such a way that each escaped label's key is followed by an equal
+// sign and then by an escaped label's value. All key-value pairs are
+// separated by a comma.
+//
+// Escaping is done by prepending a backslash before either a
+// backslash, equal sign or a comma.
+func DefaultEncoder() Encoder {
+	defaultEncoderOnce.Do(func() {
+		defaultEncoderInstance = &defaultLabelEncoder{
+			pool: sync.Pool{
+				New: func() interface{} {
+					return &bytes.Buffer{}
+				},
+			},
+		}
+	})
+	return defaultEncoderInstance
+}
+
+// Encode is a part of an implementation of the LabelEncoder
+// interface.
+func (d *defaultLabelEncoder) Encode(iter Iterator) string {
+	buf := d.pool.Get().(*bytes.Buffer)
+	defer d.pool.Put(buf)
+	buf.Reset()
+
+	for iter.Next() {
+		i, keyValue := iter.IndexedLabel()
+		if i > 0 {
+			_, _ = buf.WriteRune(',')
+		}
+		copyAndEscape(buf, string(keyValue.Key))
+
+		_, _ = buf.WriteRune('=')
+
+		if keyValue.Value.Type() == STRING {
+			copyAndEscape(buf, keyValue.Value.AsString())
+		} else {
+			_, _ = buf.WriteString(keyValue.Value.Emit())
+		}
+	}
+	return buf.String()
+}
+
+// ID is a part of an implementation of the LabelEncoder interface.
+func (*defaultLabelEncoder) ID() EncoderID {
+	return defaultEncoderID
+}
+
+// copyAndEscape escapes `=`, `,` and its own escape character (`\`),
+// making the default encoding unique.
+func copyAndEscape(buf *bytes.Buffer, val string) {
+	for _, ch := range val {
+		switch ch {
+		case '=', ',', escapeChar:
+			buf.WriteRune(escapeChar)
+		}
+		buf.WriteRune(ch)
+	}
+}
+
+// Valid returns true if this encoder ID was allocated by
+// `NewEncoderID`.  Invalid encoder IDs will not be cached.
+func (id EncoderID) Valid() bool {
+	return id.value != 0
+}

vendor/go.opentelemetry.io/otel/attribute/iterator.go

@@ -0,0 +1,143 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package attribute // import "go.opentelemetry.io/otel/attribute"
+
+// Iterator allows iterating over the set of labels in order,
+// sorted by key.
+type Iterator struct {
+	storage *Set
+	idx     int
+}
+
+// MergeIterator supports iterating over two sets of labels while
+// eliminating duplicate values from the combined set.  The first
+// iterator value takes precedence.
+type MergeIterator struct {
+	one     oneIterator
+	two     oneIterator
+	current KeyValue
+}
+
+type oneIterator struct {
+	iter  Iterator
+	done  bool
+	label KeyValue
+}
+
+// Next moves the iterator to the next position. Returns false if there
+// are no more labels.
+func (i *Iterator) Next() bool {
+	i.idx++
+	return i.idx < i.Len()
+}
+
+// Label returns current KeyValue. Must be called only after Next returns
+// true.
+func (i *Iterator) Label() KeyValue {
+	kv, _ := i.storage.Get(i.idx)
+	return kv
+}
+
+// Attribute is a synonym for Label().
+func (i *Iterator) Attribute() KeyValue {
+	return i.Label()
+}
+
+// IndexedLabel returns current index and attribute. Must be called only
+// after Next returns true.
+func (i *Iterator) IndexedLabel() (int, KeyValue) {
+	return i.idx, i.Label()
+}
+
+// Len returns a number of labels in the iterator's `*Set`.
+func (i *Iterator) Len() int {
+	return i.storage.Len()
+}
+
+// ToSlice is a convenience function that creates a slice of labels
+// from the passed iterator. The iterator is set up to start from the
+// beginning before creating the slice.
+func (i *Iterator) ToSlice() []KeyValue {
+	l := i.Len()
+	if l == 0 {
+		return nil
+	}
+	i.idx = -1
+	slice := make([]KeyValue, 0, l)
+	for i.Next() {
+		slice = append(slice, i.Label())
+	}
+	return slice
+}
+
+// NewMergeIterator returns a MergeIterator for merging two label sets
+// Duplicates are resolved by taking the value from the first set.
+func NewMergeIterator(s1, s2 *Set) MergeIterator {
+	mi := MergeIterator{
+		one: makeOne(s1.Iter()),
+		two: makeOne(s2.Iter()),
+	}
+	return mi
+}
+
+func makeOne(iter Iterator) oneIterator {
+	oi := oneIterator{
+		iter: iter,
+	}
+	oi.advance()
+	return oi
+}
+
+func (oi *oneIterator) advance() {
+	if oi.done = !oi.iter.Next(); !oi.done {
+		oi.label = oi.iter.Label()
+	}
+}
+
+// Next returns true if there is another label available.
+func (m *MergeIterator) Next() bool {
+	if m.one.done && m.two.done {
+		return false
+	}
+	if m.one.done {
+		m.current = m.two.label
+		m.two.advance()
+		return true
+	}
+	if m.two.done {
+		m.current = m.one.label
+		m.one.advance()
+		return true
+	}
+	if m.one.label.Key == m.two.label.Key {
+		m.current = m.one.label // first iterator label value wins
+		m.one.advance()
+		m.two.advance()
+		return true
+	}
+	if m.one.label.Key < m.two.label.Key {
+		m.current = m.one.label
+		m.one.advance()
+		return true
+	}
+	m.current = m.two.label
+	m.two.advance()
+	return true
+}
+
+// Label returns the current value after Next() returns true.
+func (m *MergeIterator) Label() KeyValue {
+	return m.current
+}

vendor/go.opentelemetry.io/otel/attribute/key.go

@@ -0,0 +1,102 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package attribute // import "go.opentelemetry.io/otel/attribute"
+
+// Key represents the key part in key-value pairs. It's a string. The
+// allowed character set in the key depends on the use of the key.
+type Key string
+
+// Bool creates a KeyValue instance with a BOOL Value.
+//
+// If creating both key and a bool value at the same time, then
+// instead of calling Key(name).Bool(value) consider using a
+// convenience function provided by the api/key package -
+// key.Bool(name, value).
+func (k Key) Bool(v bool) KeyValue {
+	return KeyValue{
+		Key:   k,
+		Value: BoolValue(v),
+	}
+}
+
+// Int64 creates a KeyValue instance with an INT64 Value.
+//
+// If creating both key and an int64 value at the same time, then
+// instead of calling Key(name).Int64(value) consider using a
+// convenience function provided by the api/key package -
+// key.Int64(name, value).
+func (k Key) Int64(v int64) KeyValue {
+	return KeyValue{
+		Key:   k,
+		Value: Int64Value(v),
+	}
+}
+
+// Float64 creates a KeyValue instance with a FLOAT64 Value.
+//
+// If creating both key and a float64 value at the same time, then
+// instead of calling Key(name).Float64(value) consider using a
+// convenience function provided by the api/key package -
+// key.Float64(name, value).
+func (k Key) Float64(v float64) KeyValue {
+	return KeyValue{
+		Key:   k,
+		Value: Float64Value(v),
+	}
+}
+
+// String creates a KeyValue instance with a STRING Value.
+//
+// If creating both key and a string value at the same time, then
+// instead of calling Key(name).String(value) consider using a
+// convenience function provided by the api/key package -
+// key.String(name, value).
+func (k Key) String(v string) KeyValue {
+	return KeyValue{
+		Key:   k,
+		Value: StringValue(v),
+	}
+}
+
+// Int creates a KeyValue instance with an INT64 Value.
+//
+// If creating both key and an int value at the same time, then
+// instead of calling Key(name).Int(value) consider using a
+// convenience function provided by the api/key package -
+// key.Int(name, value).
+func (k Key) Int(v int) KeyValue {
+	return KeyValue{
+		Key:   k,
+		Value: IntValue(v),
+	}
+}
+
+// Defined returns true for non-empty keys.
+func (k Key) Defined() bool {
+	return len(k) != 0
+}
+
+// Array creates a KeyValue instance with a ARRAY Value.
+//
+// If creating both key and a array value at the same time, then
+// instead of calling Key(name).String(value) consider using a
+// convenience function provided by the api/key package -
+// key.Array(name, value).
+func (k Key) Array(v interface{}) KeyValue {
+	return KeyValue{
+		Key:   k,
+		Value: ArrayValue(v),
+	}
+}

vendor/go.opentelemetry.io/otel/attribute/kv.go

@@ -0,0 +1,108 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package attribute // import "go.opentelemetry.io/otel/attribute"
+
+import (
+	"encoding/json"
+	"fmt"
+	"reflect"
+)
+
+// KeyValue holds a key and value pair.
+type KeyValue struct {
+	Key   Key
+	Value Value
+}
+
+// Valid returns if kv is a valid OpenTelemetry attribute.
+func (kv KeyValue) Valid() bool {
+	return kv.Key != "" && kv.Value.Type() != INVALID
+}
+
+// Bool creates a new key-value pair with a passed name and a bool
+// value.
+func Bool(k string, v bool) KeyValue {
+	return Key(k).Bool(v)
+}
+
+// Int64 creates a new key-value pair with a passed name and an int64
+// value.
+func Int64(k string, v int64) KeyValue {
+	return Key(k).Int64(v)
+}
+
+// Float64 creates a new key-value pair with a passed name and a float64
+// value.
+func Float64(k string, v float64) KeyValue {
+	return Key(k).Float64(v)
+}
+
+// String creates a new key-value pair with a passed name and a string
+// value.
+func String(k, v string) KeyValue {
+	return Key(k).String(v)
+}
+
+// Stringer creates a new key-value pair with a passed name and a string
+// value generated by the passed Stringer interface.
+func Stringer(k string, v fmt.Stringer) KeyValue {
+	return Key(k).String(v.String())
+}
+
+// Int creates a new key-value pair instance with a passed name and
+// either an int32 or an int64 value, depending on whether the int
+// type is 32 or 64 bits wide.
+func Int(k string, v int) KeyValue {
+	return Key(k).Int(v)
+}
+
+// Array creates a new key-value pair with a passed name and a array.
+// Only arrays of primitive type are supported.
+func Array(k string, v interface{}) KeyValue {
+	return Key(k).Array(v)
+}
+
+// Any creates a new key-value pair instance with a passed name and
+// automatic type inference. This is slower, and not type-safe.
+func Any(k string, value interface{}) KeyValue {
+	if value == nil {
+		return String(k, "<nil>")
+	}
+
+	if stringer, ok := value.(fmt.Stringer); ok {
+		return String(k, stringer.String())
+	}
+
+	rv := reflect.ValueOf(value)
+
+	switch rv.Kind() {
+	case reflect.Array, reflect.Slice:
+		return Array(k, value)
+	case reflect.Bool:
+		return Bool(k, rv.Bool())
+	case reflect.Int, reflect.Int8, reflect.Int16:
+		return Int(k, int(rv.Int()))
+	case reflect.Int64:
+		return Int64(k, rv.Int())
+	case reflect.Float64:
+		return Float64(k, rv.Float())
+	case reflect.String:
+		return String(k, rv.String())
+	}
+	if b, err := json.Marshal(value); b != nil && err == nil {
+		return String(k, string(b))
+	}
+	return String(k, fmt.Sprint(value))
+}

vendor/go.opentelemetry.io/otel/attribute/set.go

@@ -0,0 +1,471 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package attribute // import "go.opentelemetry.io/otel/attribute"
+
+import (
+	"encoding/json"
+	"reflect"
+	"sort"
+	"sync"
+)
+
+type (
+	// Set is the representation for a distinct label set.  It
+	// manages an immutable set of labels, with an internal cache
+	// for storing label encodings.
+	//
+	// This type supports the `Equivalent` method of comparison
+	// using values of type `Distinct`.
+	//
+	// This type is used to implement:
+	// 1. Metric labels
+	// 2. Resource sets
+	// 3. Correlation map (TODO)
+	Set struct {
+		equivalent Distinct
+
+		lock     sync.Mutex
+		encoders [maxConcurrentEncoders]EncoderID
+		encoded  [maxConcurrentEncoders]string
+	}
+
+	// Distinct wraps a variable-size array of `KeyValue`,
+	// constructed with keys in sorted order.  This can be used as
+	// a map key or for equality checking between Sets.
+	Distinct struct {
+		iface interface{}
+	}
+
+	// Filter supports removing certain labels from label sets.
+	// When the filter returns true, the label will be kept in
+	// the filtered label set.  When the filter returns false, the
+	// label is excluded from the filtered label set, and the
+	// label instead appears in the `removed` list of excluded labels.
+	Filter func(KeyValue) bool
+
+	// Sortable implements `sort.Interface`, used for sorting
+	// `KeyValue`.  This is an exported type to support a
+	// memory optimization.  A pointer to one of these is needed
+	// for the call to `sort.Stable()`, which the caller may
+	// provide in order to avoid an allocation.  See
+	// `NewSetWithSortable()`.
+	Sortable []KeyValue
+)
+
+var (
+	// keyValueType is used in `computeDistinctReflect`.
+	keyValueType = reflect.TypeOf(KeyValue{})
+
+	// emptySet is returned for empty label sets.
+	emptySet = &Set{
+		equivalent: Distinct{
+			iface: [0]KeyValue{},
+		},
+	}
+)
+
+const maxConcurrentEncoders = 3
+
+// EmptySet returns a reference to a Set with no elements.
+//
+// This is a convenience provided for optimized calling utility.
+func EmptySet() *Set {
+	return emptySet
+}
+
+// reflect abbreviates `reflect.ValueOf`.
+func (d Distinct) reflect() reflect.Value {
+	return reflect.ValueOf(d.iface)
+}
+
+// Valid returns true if this value refers to a valid `*Set`.
+func (d Distinct) Valid() bool {
+	return d.iface != nil
+}
+
+// Len returns the number of labels in this set.
+func (l *Set) Len() int {
+	if l == nil || !l.equivalent.Valid() {
+		return 0
+	}
+	return l.equivalent.reflect().Len()
+}
+
+// Get returns the KeyValue at ordered position `idx` in this set.
+func (l *Set) Get(idx int) (KeyValue, bool) {
+	if l == nil {
+		return KeyValue{}, false
+	}
+	value := l.equivalent.reflect()
+
+	if idx >= 0 && idx < value.Len() {
+		// Note: The Go compiler successfully avoids an allocation for
+		// the interface{} conversion here:
+		return value.Index(idx).Interface().(KeyValue), true
+	}
+
+	return KeyValue{}, false
+}
+
+// Value returns the value of a specified key in this set.
+func (l *Set) Value(k Key) (Value, bool) {
+	if l == nil {
+		return Value{}, false
+	}
+	rValue := l.equivalent.reflect()
+	vlen := rValue.Len()
+
+	idx := sort.Search(vlen, func(idx int) bool {
+		return rValue.Index(idx).Interface().(KeyValue).Key >= k
+	})
+	if idx >= vlen {
+		return Value{}, false
+	}
+	keyValue := rValue.Index(idx).Interface().(KeyValue)
+	if k == keyValue.Key {
+		return keyValue.Value, true
+	}
+	return Value{}, false
+}
+
+// HasValue tests whether a key is defined in this set.
+func (l *Set) HasValue(k Key) bool {
+	if l == nil {
+		return false
+	}
+	_, ok := l.Value(k)
+	return ok
+}
+
+// Iter returns an iterator for visiting the labels in this set.
+func (l *Set) Iter() Iterator {
+	return Iterator{
+		storage: l,
+		idx:     -1,
+	}
+}
+
+// ToSlice returns the set of labels belonging to this set, sorted,
+// where keys appear no more than once.
+func (l *Set) ToSlice() []KeyValue {
+	iter := l.Iter()
+	return iter.ToSlice()
+}
+
+// Equivalent returns a value that may be used as a map key.  The
+// Distinct type guarantees that the result will equal the equivalent
+// Distinct value of any label set with the same elements as this,
+// where sets are made unique by choosing the last value in the input
+// for any given key.
+func (l *Set) Equivalent() Distinct {
+	if l == nil || !l.equivalent.Valid() {
+		return emptySet.equivalent
+	}
+	return l.equivalent
+}
+
+// Equals returns true if the argument set is equivalent to this set.
+func (l *Set) Equals(o *Set) bool {
+	return l.Equivalent() == o.Equivalent()
+}
+
+// Encoded returns the encoded form of this set, according to
+// `encoder`.  The result will be cached in this `*Set`.
+func (l *Set) Encoded(encoder Encoder) string {
+	if l == nil || encoder == nil {
+		return ""
+	}
+
+	id := encoder.ID()
+	if !id.Valid() {
+		// Invalid IDs are not cached.
+		return encoder.Encode(l.Iter())
+	}
+
+	var lookup *string
+	l.lock.Lock()
+	for idx := 0; idx < maxConcurrentEncoders; idx++ {
+		if l.encoders[idx] == id {
+			lookup = &l.encoded[idx]
+			break
+		}
+	}
+	l.lock.Unlock()
+
+	if lookup != nil {
+		return *lookup
+	}
+
+	r := encoder.Encode(l.Iter())
+
+	l.lock.Lock()
+	defer l.lock.Unlock()
+
+	for idx := 0; idx < maxConcurrentEncoders; idx++ {
+		if l.encoders[idx] == id {
+			return l.encoded[idx]
+		}
+		if !l.encoders[idx].Valid() {
+			l.encoders[idx] = id
+			l.encoded[idx] = r
+			return r
+		}
+	}
+
+	// TODO: This is a performance cliff.  Find a way for this to
+	// generate a warning.
+	return r
+}
+
+func empty() Set {
+	return Set{
+		equivalent: emptySet.equivalent,
+	}
+}
+
+// NewSet returns a new `Set`.  See the documentation for
+// `NewSetWithSortableFiltered` for more details.
+//
+// Except for empty sets, this method adds an additional allocation
+// compared with calls that include a `*Sortable`.
+func NewSet(kvs ...KeyValue) Set {
+	// Check for empty set.
+	if len(kvs) == 0 {
+		return empty()
+	}
+	s, _ := NewSetWithSortableFiltered(kvs, new(Sortable), nil)
+	return s //nolint
+}
+
+// NewSetWithSortable returns a new `Set`.  See the documentation for
+// `NewSetWithSortableFiltered` for more details.
+//
+// This call includes a `*Sortable` option as a memory optimization.
+func NewSetWithSortable(kvs []KeyValue, tmp *Sortable) Set {
+	// Check for empty set.
+	if len(kvs) == 0 {
+		return empty()
+	}
+	s, _ := NewSetWithSortableFiltered(kvs, tmp, nil)
+	return s //nolint
+}
+
+// NewSetWithFiltered returns a new `Set`.  See the documentation for
+// `NewSetWithSortableFiltered` for more details.
+//
+// This call includes a `Filter` to include/exclude label keys from
+// the return value.  Excluded keys are returned as a slice of label
+// values.
+func NewSetWithFiltered(kvs []KeyValue, filter Filter) (Set, []KeyValue) {
+	// Check for empty set.
+	if len(kvs) == 0 {
+		return empty(), nil
+	}
+	return NewSetWithSortableFiltered(kvs, new(Sortable), filter)
+}
+
+// NewSetWithSortableFiltered returns a new `Set`.
+//
+// Duplicate keys are eliminated by taking the last value.  This
+// re-orders the input slice so that unique last-values are contiguous
+// at the end of the slice.
+//
+// This ensures the following:
+//
+// - Last-value-wins semantics
+// - Caller sees the reordering, but doesn't lose values
+// - Repeated call preserve last-value wins.
+//
+// Note that methods are defined on `*Set`, although this returns `Set`.
+// Callers can avoid memory allocations by:
+//
+// - allocating a `Sortable` for use as a temporary in this method
+// - allocating a `Set` for storing the return value of this
+//   constructor.
+//
+// The result maintains a cache of encoded labels, by attribute.EncoderID.
+// This value should not be copied after its first use.
+//
+// The second `[]KeyValue` return value is a list of labels that were
+// excluded by the Filter (if non-nil).
+func NewSetWithSortableFiltered(kvs []KeyValue, tmp *Sortable, filter Filter) (Set, []KeyValue) {
+	// Check for empty set.
+	if len(kvs) == 0 {
+		return empty(), nil
+	}
+
+	*tmp = kvs
+
+	// Stable sort so the following de-duplication can implement
+	// last-value-wins semantics.
+	sort.Stable(tmp)
+
+	*tmp = nil
+
+	position := len(kvs) - 1
+	offset := position - 1
+
+	// The requirements stated above require that the stable
+	// result be placed in the end of the input slice, while
+	// overwritten values are swapped to the beginning.
+	//
+	// De-duplicate with last-value-wins semantics.  Preserve
+	// duplicate values at the beginning of the input slice.
+	for ; offset >= 0; offset-- {
+		if kvs[offset].Key == kvs[position].Key {
+			continue
+		}
+		position--
+		kvs[offset], kvs[position] = kvs[position], kvs[offset]
+	}
+	if filter != nil {
+		return filterSet(kvs[position:], filter)
+	}
+	return Set{
+		equivalent: computeDistinct(kvs[position:]),
+	}, nil
+}
+
+// filterSet reorders `kvs` so that included keys are contiguous at
+// the end of the slice, while excluded keys precede the included keys.
+func filterSet(kvs []KeyValue, filter Filter) (Set, []KeyValue) {
+	var excluded []KeyValue
+
+	// Move labels that do not match the filter so
+	// they're adjacent before calling computeDistinct().
+	distinctPosition := len(kvs)
+
+	// Swap indistinct keys forward and distinct keys toward the
+	// end of the slice.
+	offset := len(kvs) - 1
+	for ; offset >= 0; offset-- {
+		if filter(kvs[offset]) {
+			distinctPosition--
+			kvs[offset], kvs[distinctPosition] = kvs[distinctPosition], kvs[offset]
+			continue
+		}
+	}
+	excluded = kvs[:distinctPosition]
+
+	return Set{
+		equivalent: computeDistinct(kvs[distinctPosition:]),
+	}, excluded
+}
+
+// Filter returns a filtered copy of this `Set`.  See the
+// documentation for `NewSetWithSortableFiltered` for more details.
+func (l *Set) Filter(re Filter) (Set, []KeyValue) {
+	if re == nil {
+		return Set{
+			equivalent: l.equivalent,
+		}, nil
+	}
+
+	// Note: This could be refactored to avoid the temporary slice
+	// allocation, if it proves to be expensive.
+	return filterSet(l.ToSlice(), re)
+}
+
+// computeDistinct returns a `Distinct` using either the fixed- or
+// reflect-oriented code path, depending on the size of the input.
+// The input slice is assumed to already be sorted and de-duplicated.
+func computeDistinct(kvs []KeyValue) Distinct {
+	iface := computeDistinctFixed(kvs)
+	if iface == nil {
+		iface = computeDistinctReflect(kvs)
+	}
+	return Distinct{
+		iface: iface,
+	}
+}
+
+// computeDistinctFixed computes a `Distinct` for small slices.  It
+// returns nil if the input is too large for this code path.
+func computeDistinctFixed(kvs []KeyValue) interface{} {
+	switch len(kvs) {
+	case 1:
+		ptr := new([1]KeyValue)
+		copy((*ptr)[:], kvs)
+		return *ptr
+	case 2:
+		ptr := new([2]KeyValue)
+		copy((*ptr)[:], kvs)
+		return *ptr
+	case 3:
+		ptr := new([3]KeyValue)
+		copy((*ptr)[:], kvs)
+		return *ptr
+	case 4:
+		ptr := new([4]KeyValue)
+		copy((*ptr)[:], kvs)
+		return *ptr
+	case 5:
+		ptr := new([5]KeyValue)
+		copy((*ptr)[:], kvs)
+		return *ptr
+	case 6:
+		ptr := new([6]KeyValue)
+		copy((*ptr)[:], kvs)
+		return *ptr
+	case 7:
+		ptr := new([7]KeyValue)
+		copy((*ptr)[:], kvs)
+		return *ptr
+	case 8:
+		ptr := new([8]KeyValue)
+		copy((*ptr)[:], kvs)
+		return *ptr
+	case 9:
+		ptr := new([9]KeyValue)
+		copy((*ptr)[:], kvs)
+		return *ptr
+	case 10:
+		ptr := new([10]KeyValue)
+		copy((*ptr)[:], kvs)
+		return *ptr
+	default:
+		return nil
+	}
+}
+
+// computeDistinctReflect computes a `Distinct` using reflection,
+// works for any size input.
+func computeDistinctReflect(kvs []KeyValue) interface{} {
+	at := reflect.New(reflect.ArrayOf(len(kvs), keyValueType)).Elem()
+	for i, keyValue := range kvs {
+		*(at.Index(i).Addr().Interface().(*KeyValue)) = keyValue
+	}
+	return at.Interface()
+}
+
+// MarshalJSON returns the JSON encoding of the `*Set`.
+func (l *Set) MarshalJSON() ([]byte, error) {
+	return json.Marshal(l.equivalent.iface)
+}
+
+// Len implements `sort.Interface`.
+func (l *Sortable) Len() int {
+	return len(*l)
+}
+
+// Swap implements `sort.Interface`.
+func (l *Sortable) Swap(i, j int) {
+	(*l)[i], (*l)[j] = (*l)[j], (*l)[i]
+}
+
+// Less implements `sort.Interface`.
+func (l *Sortable) Less(i, j int) bool {
+	return (*l)[i].Key < (*l)[j].Key
+}

vendor/go.opentelemetry.io/otel/attribute/type_string.go

@@ -0,0 +1,28 @@
+// Code generated by "stringer -type=Type"; DO NOT EDIT.
+
+package attribute
+
+import "strconv"
+
+func _() {
+	// An "invalid array index" compiler error signifies that the constant values have changed.
+	// Re-run the stringer command to generate them again.
+	var x [1]struct{}
+	_ = x[INVALID-0]
+	_ = x[BOOL-1]
+	_ = x[INT64-2]
+	_ = x[FLOAT64-3]
+	_ = x[STRING-4]
+	_ = x[ARRAY-5]
+}
+
+const _Type_name = "INVALIDBOOLINT64FLOAT64STRINGARRAY"
+
+var _Type_index = [...]uint8{0, 7, 11, 16, 23, 29, 34}
+
+func (i Type) String() string {
+	if i < 0 || i >= Type(len(_Type_index)-1) {
+		return "Type(" + strconv.FormatInt(int64(i), 10) + ")"
+	}
+	return _Type_name[_Type_index[i]:_Type_index[i+1]]
+}

vendor/go.opentelemetry.io/otel/attribute/value.go

@@ -0,0 +1,204 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package attribute // import "go.opentelemetry.io/otel/attribute"
+
+import (
+	"encoding/json"
+	"fmt"
+	"reflect"
+	"strconv"
+
+	"go.opentelemetry.io/otel/internal"
+)
+
+//go:generate stringer -type=Type
+
+// Type describes the type of the data Value holds.
+type Type int
+
+// Value represents the value part in key-value pairs.
+type Value struct {
+	vtype    Type
+	numeric  uint64
+	stringly string
+	// TODO Lazy value type?
+
+	array interface{}
+}
+
+const (
+	// INVALID is used for a Value with no value set.
+	INVALID Type = iota
+	// BOOL is a boolean Type Value.
+	BOOL
+	// INT64 is a 64-bit signed integral Type Value.
+	INT64
+	// FLOAT64 is a 64-bit floating point Type Value.
+	FLOAT64
+	// STRING is a string Type Value.
+	STRING
+	// ARRAY is an array Type Value used to store 1-dimensional slices or
+	// arrays of bool, int, int32, int64, uint, uint32, uint64, float,
+	// float32, float64, or string types.
+	ARRAY
+)
+
+// BoolValue creates a BOOL Value.
+func BoolValue(v bool) Value {
+	return Value{
+		vtype:   BOOL,
+		numeric: internal.BoolToRaw(v),
+	}
+}
+
+// Int64Value creates an INT64 Value.
+func Int64Value(v int64) Value {
+	return Value{
+		vtype:   INT64,
+		numeric: internal.Int64ToRaw(v),
+	}
+}
+
+// Float64Value creates a FLOAT64 Value.
+func Float64Value(v float64) Value {
+	return Value{
+		vtype:   FLOAT64,
+		numeric: internal.Float64ToRaw(v),
+	}
+}
+
+// StringValue creates a STRING Value.
+func StringValue(v string) Value {
+	return Value{
+		vtype:    STRING,
+		stringly: v,
+	}
+}
+
+// IntValue creates an INT64 Value.
+func IntValue(v int) Value {
+	return Int64Value(int64(v))
+}
+
+// ArrayValue creates an ARRAY value from an array or slice.
+// Only arrays or slices of bool, int, int64, float, float64, or string types are allowed.
+// Specifically, arrays  and slices can not contain other arrays, slices, structs, or non-standard
+// types. If the passed value is not an array or slice of these types an
+// INVALID value is returned.
+func ArrayValue(v interface{}) Value {
+	switch reflect.TypeOf(v).Kind() {
+	case reflect.Array, reflect.Slice:
+		// get array type regardless of dimensions
+		typ := reflect.TypeOf(v).Elem()
+		kind := typ.Kind()
+		switch kind {
+		case reflect.Bool, reflect.Int, reflect.Int64,
+			reflect.Float64, reflect.String:
+			val := reflect.ValueOf(v)
+			length := val.Len()
+			frozen := reflect.Indirect(reflect.New(reflect.ArrayOf(length, typ)))
+			reflect.Copy(frozen, val)
+			return Value{
+				vtype: ARRAY,
+				array: frozen.Interface(),
+			}
+		default:
+			return Value{vtype: INVALID}
+		}
+	}
+	return Value{vtype: INVALID}
+}
+
+// Type returns a type of the Value.
+func (v Value) Type() Type {
+	return v.vtype
+}
+
+// AsBool returns the bool value. Make sure that the Value's type is
+// BOOL.
+func (v Value) AsBool() bool {
+	return internal.RawToBool(v.numeric)
+}
+
+// AsInt64 returns the int64 value. Make sure that the Value's type is
+// INT64.
+func (v Value) AsInt64() int64 {
+	return internal.RawToInt64(v.numeric)
+}
+
+// AsFloat64 returns the float64 value. Make sure that the Value's
+// type is FLOAT64.
+func (v Value) AsFloat64() float64 {
+	return internal.RawToFloat64(v.numeric)
+}
+
+// AsString returns the string value. Make sure that the Value's type
+// is STRING.
+func (v Value) AsString() string {
+	return v.stringly
+}
+
+// AsArray returns the array Value as an interface{}.
+func (v Value) AsArray() interface{} {
+	return v.array
+}
+
+type unknownValueType struct{}
+
+// AsInterface returns Value's data as interface{}.
+func (v Value) AsInterface() interface{} {
+	switch v.Type() {
+	case ARRAY:
+		return v.AsArray()
+	case BOOL:
+		return v.AsBool()
+	case INT64:
+		return v.AsInt64()
+	case FLOAT64:
+		return v.AsFloat64()
+	case STRING:
+		return v.stringly
+	}
+	return unknownValueType{}
+}
+
+// Emit returns a string representation of Value's data.
+func (v Value) Emit() string {
+	switch v.Type() {
+	case ARRAY:
+		return fmt.Sprint(v.array)
+	case BOOL:
+		return strconv.FormatBool(v.AsBool())
+	case INT64:
+		return strconv.FormatInt(v.AsInt64(), 10)
+	case FLOAT64:
+		return fmt.Sprint(v.AsFloat64())
+	case STRING:
+		return v.stringly
+	default:
+		return "unknown"
+	}
+}
+
+// MarshalJSON returns the JSON encoding of the Value.
+func (v Value) MarshalJSON() ([]byte, error) {
+	var jsonVal struct {
+		Type  string
+		Value interface{}
+	}
+	jsonVal.Type = v.Type().String()
+	jsonVal.Value = v.AsInterface()
+	return json.Marshal(jsonVal)
+}

vendor/go.opentelemetry.io/otel/codes/codes.go

@@ -0,0 +1,106 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package codes // import "go.opentelemetry.io/otel/codes"
+
+import (
+	"encoding/json"
+	"fmt"
+	"strconv"
+)
+
+const (
+	// Unset is the default status code.
+	Unset Code = 0
+	// Error indicates the operation contains an error.
+	Error Code = 1
+	// Ok indicates operation has been validated by an Application developers
+	// or Operator to have completed successfully, or contain no error.
+	Ok Code = 2
+
+	maxCode = 3
+)
+
+// Code is an 32-bit representation of a status state.
+type Code uint32
+
+var codeToStr = map[Code]string{
+	Unset: "Unset",
+	Error: "Error",
+	Ok:    "Ok",
+}
+
+var strToCode = map[string]Code{
+	`"Unset"`: Unset,
+	`"Error"`: Error,
+	`"Ok"`:    Ok,
+}
+
+// String returns the Code as a string.
+func (c Code) String() string {
+	return codeToStr[c]
+}
+
+// UnmarshalJSON unmarshals b into the Code.
+//
+// This is based on the functionality in the gRPC codes package:
+// https://github.com/grpc/grpc-go/blob/bb64fee312b46ebee26be43364a7a966033521b1/codes/codes.go#L218-L244
+func (c *Code) UnmarshalJSON(b []byte) error {
+	// From json.Unmarshaler: By convention, to approximate the behavior of
+	// Unmarshal itself, Unmarshalers implement UnmarshalJSON([]byte("null")) as
+	// a no-op.
+	if string(b) == "null" {
+		return nil
+	}
+	if c == nil {
+		return fmt.Errorf("nil receiver passed to UnmarshalJSON")
+	}
+
+	var x interface{}
+	if err := json.Unmarshal(b, &x); err != nil {
+		return err
+	}
+	switch x.(type) {
+	case string:
+		if jc, ok := strToCode[string(b)]; ok {
+			*c = jc
+			return nil
+		}
+		return fmt.Errorf("invalid code: %q", string(b))
+	case float64:
+		if ci, err := strconv.ParseUint(string(b), 10, 32); err == nil {
+			if ci >= maxCode {
+				return fmt.Errorf("invalid code: %q", ci)
+			}
+
+			*c = Code(ci)
+			return nil
+		}
+		return fmt.Errorf("invalid code: %q", string(b))
+	default:
+		return fmt.Errorf("invalid code: %q", string(b))
+	}
+}
+
+// MarshalJSON returns c as the JSON encoding of c.
+func (c *Code) MarshalJSON() ([]byte, error) {
+	if c == nil {
+		return []byte("null"), nil
+	}
+	str, ok := codeToStr[*c]
+	if !ok {
+		return nil, fmt.Errorf("invalid code: %d", *c)
+	}
+	return []byte(fmt.Sprintf("%q", str)), nil
+}

vendor/go.opentelemetry.io/otel/codes/doc.go

@@ -0,0 +1,25 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+/*
+Package codes defines the canonical error codes used by OpenTelemetry.
+
+This package is currently in a pre-GA phase. Backwards incompatible changes
+may be introduced in subsequent minor version releases as we work to track
+the evolving OpenTelemetry specification and user feedback.
+
+It conforms to [the OpenTelemetry
+specification](https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/trace/api.md#statuscanonicalcode).
+*/
+package codes // import "go.opentelemetry.io/otel/codes"

vendor/go.opentelemetry.io/otel/doc.go

@@ -0,0 +1,38 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+/*
+Package otel provides global access to the OpenTelemetry API. The subpackages of
+the otel package provide an implementation of the OpenTelemetry API.
+
+This package is currently in a pre-GA phase. Backwards incompatible changes
+may be introduced in subsequent minor version releases as we work to track the
+evolving OpenTelemetry specification and user feedback.
+
+The provided API is used to instrument code and measure data about that code's
+performance and operation. The measured data, by default, is not processed or
+transmitted anywhere. An implementation of the OpenTelemetry SDK, like the
+default SDK implementation (go.opentelemetry.io/otel/sdk), and associated
+exporters are used to process and transport this data.
+
+To read the getting started guide, see https://opentelemetry.io/docs/go/getting-started/.
+
+To read more about tracing, see go.opentelemetry.io/otel/trace.
+
+To read more about metrics, see go.opentelemetry.io/otel/metric.
+
+To read more about propagation, see go.opentelemetry.io/otel/propagation and
+go.opentelemetry.io/otel/baggage.
+*/
+package otel // import "go.opentelemetry.io/otel"

vendor/go.opentelemetry.io/otel/error_handler.go

@@ -0,0 +1,22 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package otel // import "go.opentelemetry.io/otel"
+
+// ErrorHandler handles irremediable events.
+type ErrorHandler interface {
+	// Handle handles any error deemed irremediable by an OpenTelemetry
+	// component.
+	Handle(error)
+}

vendor/go.opentelemetry.io/otel/exporters/otlp/LICENSE

@@ -0,0 +1,201 @@
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
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+   See the License for the specific language governing permissions and
+   limitations under the License.

vendor/go.opentelemetry.io/otel/exporters/otlp/README.md

@@ -0,0 +1,31 @@
+# OpenTelemetry Collector Go Exporter
+
+[![PkgGoDev](https://pkg.go.dev/badge/go.opentelemetry.io/otel/exporters/otlp)](https://pkg.go.dev/go.opentelemetry.io/otel/exporters/otlp)
+
+This exporter exports OpenTelemetry spans and metrics to the OpenTelemetry Collector.
+
+
+## Installation and Setup
+
+The exporter can be installed using standard `go` functionality.
+
+```bash
+$ go get -u go.opentelemetry.io/otel/exporters/otlp
+```
+
+A new exporter can be created using the `NewExporter` function.
+
+## Retries
+
+The exporter will not, by default, retry failed requests to the collector.
+However, it is configured in a way that it can be easily enabled.
+
+To enable retries, the `GRPC_GO_RETRY` environment variable needs to be set to `on`. For example,
+
+```
+GRPC_GO_RETRY=on go run .
+```
+
+The [default service config](https://github.com/grpc/proposal/blob/master/A6-client-retries.md) used by default is defined to retry failed requests with exponential backoff (`0.3seconds * (2)^retry`) with [a max of `5` retries](https://github.com/open-telemetry/oteps/blob/be2a3fcbaa417ebbf5845cd485d34fdf0ab4a2a4/text/0035-opentelemetry-protocol.md#export-response)).
+
+These retries are only attempted for reponses that are [deemed "retry-able" by the collector](https://github.com/grpc/proposal/blob/master/A6-client-retries.md#validation-of-retrypolicy).

vendor/go.opentelemetry.io/otel/exporters/otlp/doc.go

@@ -0,0 +1,20 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package otlp contains an exporter for the OpenTelemetry protocol buffers.
+//
+// This package is currently in a pre-GA phase. Backwards incompatible changes
+// may be introduced in subsequent minor version releases as we work to track
+// the evolving OpenTelemetry specification and user feedback.
+package otlp // import "go.opentelemetry.io/otel/exporters/otlp"

vendor/go.opentelemetry.io/otel/exporters/otlp/go.mod

@@ -0,0 +1,62 @@
+module go.opentelemetry.io/otel/exporters/otlp
+
+go 1.14
+
+replace (
+	go.opentelemetry.io/otel => ../..
+	go.opentelemetry.io/otel/sdk => ../../sdk
+)
+
+require (
+	github.com/google/go-cmp v0.5.5
+	github.com/stretchr/testify v1.7.0
+	go.opentelemetry.io/otel v0.20.0
+	go.opentelemetry.io/otel/metric v0.20.0
+	go.opentelemetry.io/otel/sdk v0.20.0
+	go.opentelemetry.io/otel/sdk/export/metric v0.20.0
+	go.opentelemetry.io/otel/sdk/metric v0.20.0
+	go.opentelemetry.io/otel/trace v0.20.0
+	go.opentelemetry.io/proto/otlp v0.7.0
+	google.golang.org/grpc v1.37.0
+	google.golang.org/protobuf v1.26.0
+)
+
+replace go.opentelemetry.io/otel/bridge/opencensus => ../../bridge/opencensus
+
+replace go.opentelemetry.io/otel/bridge/opentracing => ../../bridge/opentracing
+
+replace go.opentelemetry.io/otel/example/jaeger => ../../example/jaeger
+
+replace go.opentelemetry.io/otel/example/namedtracer => ../../example/namedtracer
+
+replace go.opentelemetry.io/otel/example/opencensus => ../../example/opencensus
+
+replace go.opentelemetry.io/otel/example/otel-collector => ../../example/otel-collector
+
+replace go.opentelemetry.io/otel/example/prom-collector => ../../example/prom-collector
+
+replace go.opentelemetry.io/otel/example/prometheus => ../../example/prometheus
+
+replace go.opentelemetry.io/otel/example/zipkin => ../../example/zipkin
+
+replace go.opentelemetry.io/otel/exporters/metric/prometheus => ../metric/prometheus
+
+replace go.opentelemetry.io/otel/exporters/otlp => ./
+
+replace go.opentelemetry.io/otel/exporters/stdout => ../stdout
+
+replace go.opentelemetry.io/otel/exporters/trace/jaeger => ../trace/jaeger
+
+replace go.opentelemetry.io/otel/exporters/trace/zipkin => ../trace/zipkin
+
+replace go.opentelemetry.io/otel/internal/tools => ../../internal/tools
+
+replace go.opentelemetry.io/otel/metric => ../../metric
+
+replace go.opentelemetry.io/otel/oteltest => ../../oteltest
+
+replace go.opentelemetry.io/otel/sdk/export/metric => ../../sdk/export/metric
+
+replace go.opentelemetry.io/otel/sdk/metric => ../../sdk/metric
+
+replace go.opentelemetry.io/otel/trace => ../../trace

vendor/go.opentelemetry.io/otel/exporters/otlp/go.sum

@@ -0,0 +1,123 @@
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vendor/go.opentelemetry.io/otel/exporters/otlp/internal/otlpconfig/envconfig.go

@@ -0,0 +1,196 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package otlpconfig
+
+import (
+	"crypto/tls"
+	"fmt"
+	"io/ioutil"
+	"net/url"
+	"os"
+	"strconv"
+	"strings"
+	"time"
+
+	"go.opentelemetry.io/otel/exporters/otlp"
+
+	"go.opentelemetry.io/otel"
+)
+
+func ApplyGRPCEnvConfigs(cfg *Config) {
+	e := EnvOptionsReader{
+		GetEnv:   os.Getenv,
+		ReadFile: ioutil.ReadFile,
+	}
+
+	e.ApplyGRPCEnvConfigs(cfg)
+}
+
+func ApplyHTTPEnvConfigs(cfg *Config) {
+	e := EnvOptionsReader{
+		GetEnv:   os.Getenv,
+		ReadFile: ioutil.ReadFile,
+	}
+
+	e.ApplyHTTPEnvConfigs(cfg)
+}
+
+type EnvOptionsReader struct {
+	GetEnv   func(string) string
+	ReadFile func(filename string) ([]byte, error)
+}
+
+func (e *EnvOptionsReader) ApplyHTTPEnvConfigs(cfg *Config) {
+	opts := e.GetOptionsFromEnv()
+	for _, opt := range opts {
+		opt.ApplyHTTPOption(cfg)
+	}
+}
+
+func (e *EnvOptionsReader) ApplyGRPCEnvConfigs(cfg *Config) {
+	opts := e.GetOptionsFromEnv()
+	for _, opt := range opts {
+		opt.ApplyGRPCOption(cfg)
+	}
+}
+
+func (e *EnvOptionsReader) GetOptionsFromEnv() []GenericOption {
+	var opts []GenericOption
+
+	// Endpoint
+	if v, ok := e.getEnvValue("ENDPOINT"); ok {
+		opts = append(opts, WithEndpoint(v))
+	}
+	if v, ok := e.getEnvValue("TRACES_ENDPOINT"); ok {
+		opts = append(opts, WithTracesEndpoint(v))
+	}
+	if v, ok := e.getEnvValue("METRICS_ENDPOINT"); ok {
+		opts = append(opts, WithMetricsEndpoint(v))
+	}
+
+	// Certificate File
+	if path, ok := e.getEnvValue("CERTIFICATE"); ok {
+		if tls, err := e.readTLSConfig(path); err == nil {
+			opts = append(opts, WithTLSClientConfig(tls))
+		} else {
+			otel.Handle(fmt.Errorf("failed to configure otlp exporter certificate '%s': %w", path, err))
+		}
+	}
+	if path, ok := e.getEnvValue("TRACES_CERTIFICATE"); ok {
+		if tls, err := e.readTLSConfig(path); err == nil {
+			opts = append(opts, WithTracesTLSClientConfig(tls))
+		} else {
+			otel.Handle(fmt.Errorf("failed to configure otlp traces exporter certificate '%s': %w", path, err))
+		}
+	}
+	if path, ok := e.getEnvValue("METRICS_CERTIFICATE"); ok {
+		if tls, err := e.readTLSConfig(path); err == nil {
+			opts = append(opts, WithMetricsTLSClientConfig(tls))
+		} else {
+			otel.Handle(fmt.Errorf("failed to configure otlp metrics exporter certificate '%s': %w", path, err))
+		}
+	}
+
+	// Headers
+	if h, ok := e.getEnvValue("HEADERS"); ok {
+		opts = append(opts, WithHeaders(stringToHeader(h)))
+	}
+	if h, ok := e.getEnvValue("TRACES_HEADERS"); ok {
+		opts = append(opts, WithTracesHeaders(stringToHeader(h)))
+	}
+	if h, ok := e.getEnvValue("METRICS_HEADERS"); ok {
+		opts = append(opts, WithMetricsHeaders(stringToHeader(h)))
+	}
+
+	// Compression
+	if c, ok := e.getEnvValue("COMPRESSION"); ok {
+		opts = append(opts, WithCompression(stringToCompression(c)))
+	}
+	if c, ok := e.getEnvValue("TRACES_COMPRESSION"); ok {
+		opts = append(opts, WithTracesCompression(stringToCompression(c)))
+	}
+	if c, ok := e.getEnvValue("METRICS_COMPRESSION"); ok {
+		opts = append(opts, WithMetricsCompression(stringToCompression(c)))
+	}
+
+	// Timeout
+	if t, ok := e.getEnvValue("TIMEOUT"); ok {
+		if d, err := strconv.Atoi(t); err == nil {
+			opts = append(opts, WithTimeout(time.Duration(d)*time.Millisecond))
+		}
+	}
+	if t, ok := e.getEnvValue("TRACES_TIMEOUT"); ok {
+		if d, err := strconv.Atoi(t); err == nil {
+			opts = append(opts, WithTracesTimeout(time.Duration(d)*time.Millisecond))
+		}
+	}
+	if t, ok := e.getEnvValue("METRICS_TIMEOUT"); ok {
+		if d, err := strconv.Atoi(t); err == nil {
+			opts = append(opts, WithMetricsTimeout(time.Duration(d)*time.Millisecond))
+		}
+	}
+
+	return opts
+}
+
+// getEnvValue gets an OTLP environment variable value of the specified key using the GetEnv function.
+// This function already prepends the OTLP prefix to all key lookup.
+func (e *EnvOptionsReader) getEnvValue(key string) (string, bool) {
+	v := strings.TrimSpace(e.GetEnv(fmt.Sprintf("OTEL_EXPORTER_OTLP_%s", key)))
+	return v, v != ""
+}
+
+func (e *EnvOptionsReader) readTLSConfig(path string) (*tls.Config, error) {
+	b, err := e.ReadFile(path)
+	if err != nil {
+		return nil, err
+	}
+	return CreateTLSConfig(b)
+}
+
+func stringToCompression(value string) otlp.Compression {
+	switch value {
+	case "gzip":
+		return otlp.GzipCompression
+	}
+
+	return otlp.NoCompression
+}
+
+func stringToHeader(value string) map[string]string {
+	headersPairs := strings.Split(value, ",")
+	headers := make(map[string]string)
+
+	for _, header := range headersPairs {
+		nameValue := strings.SplitN(header, "=", 2)
+		if len(nameValue) < 2 {
+			continue
+		}
+		name, err := url.QueryUnescape(nameValue[0])
+		if err != nil {
+			continue
+		}
+		trimmedName := strings.TrimSpace(name)
+		value, err := url.QueryUnescape(nameValue[1])
+		if err != nil {
+			continue
+		}
+		trimmedValue := strings.TrimSpace(value)
+
+		headers[trimmedName] = trimmedValue
+	}
+
+	return headers
+}

vendor/go.opentelemetry.io/otel/exporters/otlp/internal/otlpconfig/options.go

@@ -0,0 +1,376 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package otlpconfig // import "go.opentelemetry.io/otel/exporters/otlp/internal/otlpconfig"
+
+import (
+	"crypto/tls"
+	"fmt"
+	"time"
+
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/credentials"
+
+	"go.opentelemetry.io/otel/exporters/otlp"
+)
+
+const (
+	// DefaultMaxAttempts describes how many times the driver
+	// should retry the sending of the payload in case of a
+	// retryable error.
+	DefaultMaxAttempts int = 5
+	// DefaultTracesPath is a default URL path for endpoint that
+	// receives spans.
+	DefaultTracesPath string = "/v1/traces"
+	// DefaultMetricsPath is a default URL path for endpoint that
+	// receives metrics.
+	DefaultMetricsPath string = "/v1/metrics"
+	// DefaultBackoff is a default base backoff time used in the
+	// exponential backoff strategy.
+	DefaultBackoff time.Duration = 300 * time.Millisecond
+	// DefaultTimeout is a default max waiting time for the backend to process
+	// each span or metrics batch.
+	DefaultTimeout time.Duration = 10 * time.Second
+	// DefaultServiceConfig is the gRPC service config used if none is
+	// provided by the user.
+	DefaultServiceConfig = `{
+	"methodConfig":[{
+		"name":[
+			{ "service":"opentelemetry.proto.collector.metrics.v1.MetricsService" },
+			{ "service":"opentelemetry.proto.collector.trace.v1.TraceService" }
+		],
+		"retryPolicy":{
+			"MaxAttempts":5,
+			"InitialBackoff":"0.3s",
+			"MaxBackoff":"5s",
+			"BackoffMultiplier":2,
+			"RetryableStatusCodes":[
+				"CANCELLED",
+				"DEADLINE_EXCEEDED",
+				"RESOURCE_EXHAUSTED",
+				"ABORTED",
+				"OUT_OF_RANGE",
+				"UNAVAILABLE",
+				"DATA_LOSS"
+			]
+		}
+	}]
+}`
+)
+
+type (
+	SignalConfig struct {
+		Endpoint    string
+		Insecure    bool
+		TLSCfg      *tls.Config
+		Headers     map[string]string
+		Compression otlp.Compression
+		Timeout     time.Duration
+		URLPath     string
+
+		// gRPC configurations
+		GRPCCredentials credentials.TransportCredentials
+	}
+
+	Config struct {
+		// Signal specific configurations
+		Metrics SignalConfig
+		Traces  SignalConfig
+
+		// General configurations
+		MaxAttempts int
+		Backoff     time.Duration
+
+		// HTTP configuration
+		Marshaler otlp.Marshaler
+
+		// gRPC configurations
+		ReconnectionPeriod time.Duration
+		ServiceConfig      string
+		DialOptions        []grpc.DialOption
+	}
+)
+
+func NewDefaultConfig() Config {
+	c := Config{
+		Traces: SignalConfig{
+			Endpoint:    fmt.Sprintf("%s:%d", otlp.DefaultCollectorHost, otlp.DefaultCollectorPort),
+			URLPath:     DefaultTracesPath,
+			Compression: otlp.NoCompression,
+			Timeout:     DefaultTimeout,
+		},
+		Metrics: SignalConfig{
+			Endpoint:    fmt.Sprintf("%s:%d", otlp.DefaultCollectorHost, otlp.DefaultCollectorPort),
+			URLPath:     DefaultMetricsPath,
+			Compression: otlp.NoCompression,
+			Timeout:     DefaultTimeout,
+		},
+		MaxAttempts:   DefaultMaxAttempts,
+		Backoff:       DefaultBackoff,
+		ServiceConfig: DefaultServiceConfig,
+	}
+
+	return c
+}
+
+type (
+	// GenericOption applies an option to the HTTP or gRPC driver.
+	GenericOption interface {
+		ApplyHTTPOption(*Config)
+		ApplyGRPCOption(*Config)
+
+		// A private method to prevent users implementing the
+		// interface and so future additions to it will not
+		// violate compatibility.
+		private()
+	}
+
+	// HTTPOption applies an option to the HTTP driver.
+	HTTPOption interface {
+		ApplyHTTPOption(*Config)
+
+		// A private method to prevent users implementing the
+		// interface and so future additions to it will not
+		// violate compatibility.
+		private()
+	}
+
+	// GRPCOption applies an option to the gRPC driver.
+	GRPCOption interface {
+		ApplyGRPCOption(*Config)
+
+		// A private method to prevent users implementing the
+		// interface and so future additions to it will not
+		// violate compatibility.
+		private()
+	}
+)
+
+// genericOption is an option that applies the same logic
+// for both gRPC and HTTP.
+type genericOption struct {
+	fn func(*Config)
+}
+
+func (g *genericOption) ApplyGRPCOption(cfg *Config) {
+	g.fn(cfg)
+}
+
+func (g *genericOption) ApplyHTTPOption(cfg *Config) {
+	g.fn(cfg)
+}
+
+func (genericOption) private() {}
+
+func newGenericOption(fn func(cfg *Config)) GenericOption {
+	return &genericOption{fn: fn}
+}
+
+// splitOption is an option that applies different logics
+// for gRPC and HTTP.
+type splitOption struct {
+	httpFn func(*Config)
+	grpcFn func(*Config)
+}
+
+func (g *splitOption) ApplyGRPCOption(cfg *Config) {
+	g.grpcFn(cfg)
+}
+
+func (g *splitOption) ApplyHTTPOption(cfg *Config) {
+	g.httpFn(cfg)
+}
+
+func (splitOption) private() {}
+
+func newSplitOption(httpFn func(cfg *Config), grpcFn func(cfg *Config)) GenericOption {
+	return &splitOption{httpFn: httpFn, grpcFn: grpcFn}
+}
+
+// httpOption is an option that is only applied to the HTTP driver.
+type httpOption struct {
+	fn func(*Config)
+}
+
+func (h *httpOption) ApplyHTTPOption(cfg *Config) {
+	h.fn(cfg)
+}
+
+func (httpOption) private() {}
+
+func NewHTTPOption(fn func(cfg *Config)) HTTPOption {
+	return &httpOption{fn: fn}
+}
+
+// grpcOption is an option that is only applied to the gRPC driver.
+type grpcOption struct {
+	fn func(*Config)
+}
+
+func (h *grpcOption) ApplyGRPCOption(cfg *Config) {
+	h.fn(cfg)
+}
+
+func (grpcOption) private() {}
+
+func NewGRPCOption(fn func(cfg *Config)) GRPCOption {
+	return &grpcOption{fn: fn}
+}
+
+// Generic Options
+
+func WithEndpoint(endpoint string) GenericOption {
+	return newGenericOption(func(cfg *Config) {
+		cfg.Traces.Endpoint = endpoint
+		cfg.Metrics.Endpoint = endpoint
+	})
+}
+
+func WithTracesEndpoint(endpoint string) GenericOption {
+	return newGenericOption(func(cfg *Config) {
+		cfg.Traces.Endpoint = endpoint
+	})
+}
+
+func WithMetricsEndpoint(endpoint string) GenericOption {
+	return newGenericOption(func(cfg *Config) {
+		cfg.Metrics.Endpoint = endpoint
+	})
+}
+
+func WithCompression(compression otlp.Compression) GenericOption {
+	return newGenericOption(func(cfg *Config) {
+		cfg.Traces.Compression = compression
+		cfg.Metrics.Compression = compression
+	})
+}
+
+func WithTracesCompression(compression otlp.Compression) GenericOption {
+	return newGenericOption(func(cfg *Config) {
+		cfg.Traces.Compression = compression
+	})
+}
+
+func WithMetricsCompression(compression otlp.Compression) GenericOption {
+	return newGenericOption(func(cfg *Config) {
+		cfg.Metrics.Compression = compression
+	})
+}
+
+func WithTracesURLPath(urlPath string) GenericOption {
+	return newGenericOption(func(cfg *Config) {
+		cfg.Traces.URLPath = urlPath
+	})
+}
+
+func WithMetricsURLPath(urlPath string) GenericOption {
+	return newGenericOption(func(cfg *Config) {
+		cfg.Metrics.URLPath = urlPath
+	})
+}
+
+func WithMaxAttempts(maxAttempts int) GenericOption {
+	return newGenericOption(func(cfg *Config) {
+		cfg.MaxAttempts = maxAttempts
+	})
+}
+
+func WithBackoff(duration time.Duration) GenericOption {
+	return newGenericOption(func(cfg *Config) {
+		cfg.Backoff = duration
+	})
+}
+
+func WithTLSClientConfig(tlsCfg *tls.Config) GenericOption {
+	return newSplitOption(func(cfg *Config) {
+		cfg.Traces.TLSCfg = tlsCfg.Clone()
+		cfg.Metrics.TLSCfg = tlsCfg.Clone()
+	}, func(cfg *Config) {
+		cfg.Traces.GRPCCredentials = credentials.NewTLS(tlsCfg)
+		cfg.Metrics.GRPCCredentials = credentials.NewTLS(tlsCfg)
+	})
+}
+
+func WithTracesTLSClientConfig(tlsCfg *tls.Config) GenericOption {
+	return newSplitOption(func(cfg *Config) {
+		cfg.Traces.TLSCfg = tlsCfg.Clone()
+	}, func(cfg *Config) {
+		cfg.Traces.GRPCCredentials = credentials.NewTLS(tlsCfg)
+	})
+}
+
+func WithMetricsTLSClientConfig(tlsCfg *tls.Config) GenericOption {
+	return newSplitOption(func(cfg *Config) {
+		cfg.Metrics.TLSCfg = tlsCfg.Clone()
+	}, func(cfg *Config) {
+		cfg.Metrics.GRPCCredentials = credentials.NewTLS(tlsCfg)
+	})
+}
+
+func WithInsecure() GenericOption {
+	return newGenericOption(func(cfg *Config) {
+		cfg.Traces.Insecure = true
+		cfg.Metrics.Insecure = true
+	})
+}
+
+func WithInsecureTraces() GenericOption {
+	return newGenericOption(func(cfg *Config) {
+		cfg.Traces.Insecure = true
+	})
+}
+
+func WithInsecureMetrics() GenericOption {
+	return newGenericOption(func(cfg *Config) {
+		cfg.Metrics.Insecure = true
+	})
+}
+
+func WithHeaders(headers map[string]string) GenericOption {
+	return newGenericOption(func(cfg *Config) {
+		cfg.Traces.Headers = headers
+		cfg.Metrics.Headers = headers
+	})
+}
+
+func WithTracesHeaders(headers map[string]string) GenericOption {
+	return newGenericOption(func(cfg *Config) {
+		cfg.Traces.Headers = headers
+	})
+}
+
+func WithMetricsHeaders(headers map[string]string) GenericOption {
+	return newGenericOption(func(cfg *Config) {
+		cfg.Metrics.Headers = headers
+	})
+}
+
+func WithTimeout(duration time.Duration) GenericOption {
+	return newGenericOption(func(cfg *Config) {
+		cfg.Traces.Timeout = duration
+		cfg.Metrics.Timeout = duration
+	})
+}
+
+func WithTracesTimeout(duration time.Duration) GenericOption {
+	return newGenericOption(func(cfg *Config) {
+		cfg.Traces.Timeout = duration
+	})
+}
+
+func WithMetricsTimeout(duration time.Duration) GenericOption {
+	return newGenericOption(func(cfg *Config) {
+		cfg.Metrics.Timeout = duration
+	})
+}

vendor/go.opentelemetry.io/otel/exporters/otlp/internal/otlpconfig/tls.go

@@ -0,0 +1,69 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package otlpconfig
+
+import (
+	"crypto/tls"
+	"crypto/x509"
+	"errors"
+	"io/ioutil"
+)
+
+const (
+	WeakCertificate = `
+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----
+`
+	WeakPrivateKey = `
+-----BEGIN PRIVATE KEY-----
+MIGHAgEAMBMGByqGSM49AgEGCCqGSM49AwEHBG0wawIBAQQgN8HEXiXhvByrJ1zK
+SFT6Y2l2KqDWwWzKf+t4CyWrNKehRANCAAS9nWSkmPCxShxnp43F+PrOtbGV7sNf
+kbQ/kxzi9Ego0ZJdiXxkmv/C05QFddCW7Y0ZsJCLHGogQsYnWJBXUZOV
+-----END PRIVATE KEY-----
+`
+)
+
+// ReadTLSConfigFromFile reads a PEM certificate file and creates
+// a tls.Config that will use this certifate to verify a server certificate.
+func ReadTLSConfigFromFile(path string) (*tls.Config, error) {
+	b, err := ioutil.ReadFile(path)
+	if err != nil {
+		return nil, err
+	}
+
+	return CreateTLSConfig(b)
+}
+
+// CreateTLSConfig creates a tls.Config from a raw certificate bytes
+// to verify a server certificate.
+func CreateTLSConfig(certBytes []byte) (*tls.Config, error) {
+	cp := x509.NewCertPool()
+	if ok := cp.AppendCertsFromPEM(certBytes); !ok {
+		return nil, errors.New("failed to append certificate to the cert pool")
+	}
+
+	return &tls.Config{
+		RootCAs: cp,
+	}, nil
+}

vendor/go.opentelemetry.io/otel/exporters/otlp/internal/transform/attribute.go

@@ -0,0 +1,141 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package transform
+
+import (
+	"reflect"
+
+	"go.opentelemetry.io/otel/attribute"
+	commonpb "go.opentelemetry.io/proto/otlp/common/v1"
+
+	"go.opentelemetry.io/otel/sdk/resource"
+)
+
+// Attributes transforms a slice of KeyValues into a slice of OTLP attribute key-values.
+func Attributes(attrs []attribute.KeyValue) []*commonpb.KeyValue {
+	if len(attrs) == 0 {
+		return nil
+	}
+
+	out := make([]*commonpb.KeyValue, 0, len(attrs))
+	for _, kv := range attrs {
+		out = append(out, toAttribute(kv))
+	}
+	return out
+}
+
+// ResourceAttributes transforms a Resource into a slice of OTLP attribute key-values.
+func ResourceAttributes(resource *resource.Resource) []*commonpb.KeyValue {
+	if resource.Len() == 0 {
+		return nil
+	}
+
+	out := make([]*commonpb.KeyValue, 0, resource.Len())
+	for iter := resource.Iter(); iter.Next(); {
+		out = append(out, toAttribute(iter.Attribute()))
+	}
+
+	return out
+}
+
+func toAttribute(v attribute.KeyValue) *commonpb.KeyValue {
+	result := &commonpb.KeyValue{
+		Key:   string(v.Key),
+		Value: new(commonpb.AnyValue),
+	}
+	switch v.Value.Type() {
+	case attribute.BOOL:
+		result.Value.Value = &commonpb.AnyValue_BoolValue{
+			BoolValue: v.Value.AsBool(),
+		}
+	case attribute.INT64:
+		result.Value.Value = &commonpb.AnyValue_IntValue{
+			IntValue: v.Value.AsInt64(),
+		}
+	case attribute.FLOAT64:
+		result.Value.Value = &commonpb.AnyValue_DoubleValue{
+			DoubleValue: v.Value.AsFloat64(),
+		}
+	case attribute.STRING:
+		result.Value.Value = &commonpb.AnyValue_StringValue{
+			StringValue: v.Value.AsString(),
+		}
+	case attribute.ARRAY:
+		result.Value.Value = &commonpb.AnyValue_ArrayValue{
+			ArrayValue: &commonpb.ArrayValue{
+				Values: arrayValues(v),
+			},
+		}
+	default:
+		result.Value.Value = &commonpb.AnyValue_StringValue{
+			StringValue: "INVALID",
+		}
+	}
+	return result
+}
+
+func arrayValues(kv attribute.KeyValue) []*commonpb.AnyValue {
+	a := kv.Value.AsArray()
+	aType := reflect.TypeOf(a)
+	var valueFunc func(reflect.Value) *commonpb.AnyValue
+	switch aType.Elem().Kind() {
+	case reflect.Bool:
+		valueFunc = func(v reflect.Value) *commonpb.AnyValue {
+			return &commonpb.AnyValue{
+				Value: &commonpb.AnyValue_BoolValue{
+					BoolValue: v.Bool(),
+				},
+			}
+		}
+	case reflect.Int, reflect.Int64:
+		valueFunc = func(v reflect.Value) *commonpb.AnyValue {
+			return &commonpb.AnyValue{
+				Value: &commonpb.AnyValue_IntValue{
+					IntValue: v.Int(),
+				},
+			}
+		}
+	case reflect.Uintptr:
+		valueFunc = func(v reflect.Value) *commonpb.AnyValue {
+			return &commonpb.AnyValue{
+				Value: &commonpb.AnyValue_IntValue{
+					IntValue: int64(v.Uint()),
+				},
+			}
+		}
+	case reflect.Float64:
+		valueFunc = func(v reflect.Value) *commonpb.AnyValue {
+			return &commonpb.AnyValue{
+				Value: &commonpb.AnyValue_DoubleValue{
+					DoubleValue: v.Float(),
+				},
+			}
+		}
+	case reflect.String:
+		valueFunc = func(v reflect.Value) *commonpb.AnyValue {
+			return &commonpb.AnyValue{
+				Value: &commonpb.AnyValue_StringValue{
+					StringValue: v.String(),
+				},
+			}
+		}
+	}
+
+	results := make([]*commonpb.AnyValue, aType.Len())
+	for i, aValue := 0, reflect.ValueOf(a); i < aValue.Len(); i++ {
+		results[i] = valueFunc(aValue.Index(i))
+	}
+	return results
+}

vendor/go.opentelemetry.io/otel/exporters/otlp/internal/transform/instrumentation.go

@@ -0,0 +1,31 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package transform
+
+import (
+	commonpb "go.opentelemetry.io/proto/otlp/common/v1"
+
+	"go.opentelemetry.io/otel/sdk/instrumentation"
+)
+
+func instrumentationLibrary(il instrumentation.Library) *commonpb.InstrumentationLibrary {
+	if il == (instrumentation.Library{}) {
+		return nil
+	}
+	return &commonpb.InstrumentationLibrary{
+		Name:    il.Name,
+		Version: il.Version,
+	}
+}

vendor/go.opentelemetry.io/otel/exporters/otlp/internal/transform/metric.go

@@ -0,0 +1,631 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package transform provides translations for opentelemetry-go concepts and
+// structures to otlp structures.
+package transform
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"strings"
+	"sync"
+	"time"
+
+	"go.opentelemetry.io/otel/attribute"
+	commonpb "go.opentelemetry.io/proto/otlp/common/v1"
+	metricpb "go.opentelemetry.io/proto/otlp/metrics/v1"
+	resourcepb "go.opentelemetry.io/proto/otlp/resource/v1"
+
+	"go.opentelemetry.io/otel/metric/number"
+	export "go.opentelemetry.io/otel/sdk/export/metric"
+	"go.opentelemetry.io/otel/sdk/export/metric/aggregation"
+	"go.opentelemetry.io/otel/sdk/instrumentation"
+	"go.opentelemetry.io/otel/sdk/resource"
+)
+
+var (
+	// ErrUnimplementedAgg is returned when a transformation of an unimplemented
+	// aggregator is attempted.
+	ErrUnimplementedAgg = errors.New("unimplemented aggregator")
+
+	// ErrIncompatibleAgg is returned when
+	// aggregation.Kind implies an interface conversion that has
+	// failed
+	ErrIncompatibleAgg = errors.New("incompatible aggregation type")
+
+	// ErrUnknownValueType is returned when a transformation of an unknown value
+	// is attempted.
+	ErrUnknownValueType = errors.New("invalid value type")
+
+	// ErrContextCanceled is returned when a context cancellation halts a
+	// transformation.
+	ErrContextCanceled = errors.New("context canceled")
+
+	// ErrTransforming is returned when an unexected error is encoutered transforming.
+	ErrTransforming = errors.New("transforming failed")
+)
+
+// result is the product of transforming Records into OTLP Metrics.
+type result struct {
+	Resource               *resource.Resource
+	InstrumentationLibrary instrumentation.Library
+	Metric                 *metricpb.Metric
+	Err                    error
+}
+
+// toNanos returns the number of nanoseconds since the UNIX epoch.
+func toNanos(t time.Time) uint64 {
+	if t.IsZero() {
+		return 0
+	}
+	return uint64(t.UnixNano())
+}
+
+// CheckpointSet transforms all records contained in a checkpoint into
+// batched OTLP ResourceMetrics.
+func CheckpointSet(ctx context.Context, exportSelector export.ExportKindSelector, cps export.CheckpointSet, numWorkers uint) ([]*metricpb.ResourceMetrics, error) {
+	records, errc := source(ctx, exportSelector, cps)
+
+	// Start a fixed number of goroutines to transform records.
+	transformed := make(chan result)
+	var wg sync.WaitGroup
+	wg.Add(int(numWorkers))
+	for i := uint(0); i < numWorkers; i++ {
+		go func() {
+			defer wg.Done()
+			transformer(ctx, exportSelector, records, transformed)
+		}()
+	}
+	go func() {
+		wg.Wait()
+		close(transformed)
+	}()
+
+	// Synchronously collect the transformed records and transmit.
+	rms, err := sink(ctx, transformed)
+	if err != nil {
+		return nil, err
+	}
+
+	// source is complete, check for any errors.
+	if err := <-errc; err != nil {
+		return nil, err
+	}
+	return rms, nil
+}
+
+// source starts a goroutine that sends each one of the Records yielded by
+// the CheckpointSet on the returned chan. Any error encoutered will be sent
+// on the returned error chan after seeding is complete.
+func source(ctx context.Context, exportSelector export.ExportKindSelector, cps export.CheckpointSet) (<-chan export.Record, <-chan error) {
+	errc := make(chan error, 1)
+	out := make(chan export.Record)
+	// Seed records into process.
+	go func() {
+		defer close(out)
+		// No select is needed since errc is buffered.
+		errc <- cps.ForEach(exportSelector, func(r export.Record) error {
+			select {
+			case <-ctx.Done():
+				return ErrContextCanceled
+			case out <- r:
+			}
+			return nil
+		})
+	}()
+	return out, errc
+}
+
+// transformer transforms records read from the passed in chan into
+// OTLP Metrics which are sent on the out chan.
+func transformer(ctx context.Context, exportSelector export.ExportKindSelector, in <-chan export.Record, out chan<- result) {
+	for r := range in {
+		m, err := Record(exportSelector, r)
+		// Propagate errors, but do not send empty results.
+		if err == nil && m == nil {
+			continue
+		}
+		res := result{
+			Resource: r.Resource(),
+			InstrumentationLibrary: instrumentation.Library{
+				Name:    r.Descriptor().InstrumentationName(),
+				Version: r.Descriptor().InstrumentationVersion(),
+			},
+			Metric: m,
+			Err:    err,
+		}
+		select {
+		case <-ctx.Done():
+			return
+		case out <- res:
+		}
+	}
+}
+
+// sink collects transformed Records and batches them.
+//
+// Any errors encoutered transforming input will be reported with an
+// ErrTransforming as well as the completed ResourceMetrics. It is up to the
+// caller to handle any incorrect data in these ResourceMetrics.
+func sink(ctx context.Context, in <-chan result) ([]*metricpb.ResourceMetrics, error) {
+	var errStrings []string
+
+	type resourceBatch struct {
+		Resource *resourcepb.Resource
+		// Group by instrumentation library name and then the MetricDescriptor.
+		InstrumentationLibraryBatches map[instrumentation.Library]map[string]*metricpb.Metric
+	}
+
+	// group by unique Resource string.
+	grouped := make(map[attribute.Distinct]resourceBatch)
+	for res := range in {
+		if res.Err != nil {
+			errStrings = append(errStrings, res.Err.Error())
+			continue
+		}
+
+		rID := res.Resource.Equivalent()
+		rb, ok := grouped[rID]
+		if !ok {
+			rb = resourceBatch{
+				Resource:                      Resource(res.Resource),
+				InstrumentationLibraryBatches: make(map[instrumentation.Library]map[string]*metricpb.Metric),
+			}
+			grouped[rID] = rb
+		}
+
+		mb, ok := rb.InstrumentationLibraryBatches[res.InstrumentationLibrary]
+		if !ok {
+			mb = make(map[string]*metricpb.Metric)
+			rb.InstrumentationLibraryBatches[res.InstrumentationLibrary] = mb
+		}
+
+		mID := res.Metric.GetName()
+		m, ok := mb[mID]
+		if !ok {
+			mb[mID] = res.Metric
+			continue
+		}
+		switch res.Metric.Data.(type) {
+		case *metricpb.Metric_IntGauge:
+			m.GetIntGauge().DataPoints = append(m.GetIntGauge().DataPoints, res.Metric.GetIntGauge().DataPoints...)
+		case *metricpb.Metric_IntHistogram:
+			m.GetIntHistogram().DataPoints = append(m.GetIntHistogram().DataPoints, res.Metric.GetIntHistogram().DataPoints...)
+		case *metricpb.Metric_IntSum:
+			m.GetIntSum().DataPoints = append(m.GetIntSum().DataPoints, res.Metric.GetIntSum().DataPoints...)
+		case *metricpb.Metric_DoubleGauge:
+			m.GetDoubleGauge().DataPoints = append(m.GetDoubleGauge().DataPoints, res.Metric.GetDoubleGauge().DataPoints...)
+		case *metricpb.Metric_DoubleHistogram:
+			m.GetDoubleHistogram().DataPoints = append(m.GetDoubleHistogram().DataPoints, res.Metric.GetDoubleHistogram().DataPoints...)
+		case *metricpb.Metric_DoubleSum:
+			m.GetDoubleSum().DataPoints = append(m.GetDoubleSum().DataPoints, res.Metric.GetDoubleSum().DataPoints...)
+		default:
+		}
+	}
+
+	if len(grouped) == 0 {
+		return nil, nil
+	}
+
+	var rms []*metricpb.ResourceMetrics
+	for _, rb := range grouped {
+		rm := &metricpb.ResourceMetrics{Resource: rb.Resource}
+		for il, mb := range rb.InstrumentationLibraryBatches {
+			ilm := &metricpb.InstrumentationLibraryMetrics{
+				Metrics: make([]*metricpb.Metric, 0, len(mb)),
+			}
+			if il != (instrumentation.Library{}) {
+				ilm.InstrumentationLibrary = &commonpb.InstrumentationLibrary{
+					Name:    il.Name,
+					Version: il.Version,
+				}
+			}
+			for _, m := range mb {
+				ilm.Metrics = append(ilm.Metrics, m)
+			}
+			rm.InstrumentationLibraryMetrics = append(rm.InstrumentationLibraryMetrics, ilm)
+		}
+		rms = append(rms, rm)
+	}
+
+	// Report any transform errors.
+	if len(errStrings) > 0 {
+		return rms, fmt.Errorf("%w:\n -%s", ErrTransforming, strings.Join(errStrings, "\n -"))
+	}
+	return rms, nil
+}
+
+// Record transforms a Record into an OTLP Metric. An ErrIncompatibleAgg
+// error is returned if the Record Aggregator is not supported.
+func Record(exportSelector export.ExportKindSelector, r export.Record) (*metricpb.Metric, error) {
+	agg := r.Aggregation()
+	switch agg.Kind() {
+	case aggregation.MinMaxSumCountKind:
+		mmsc, ok := agg.(aggregation.MinMaxSumCount)
+		if !ok {
+			return nil, fmt.Errorf("%w: %T", ErrIncompatibleAgg, agg)
+		}
+		return minMaxSumCount(r, mmsc)
+
+	case aggregation.HistogramKind:
+		h, ok := agg.(aggregation.Histogram)
+		if !ok {
+			return nil, fmt.Errorf("%w: %T", ErrIncompatibleAgg, agg)
+		}
+		return histogramPoint(r, exportSelector.ExportKindFor(r.Descriptor(), aggregation.HistogramKind), h)
+
+	case aggregation.SumKind:
+		s, ok := agg.(aggregation.Sum)
+		if !ok {
+			return nil, fmt.Errorf("%w: %T", ErrIncompatibleAgg, agg)
+		}
+		sum, err := s.Sum()
+		if err != nil {
+			return nil, err
+		}
+		return sumPoint(r, sum, r.StartTime(), r.EndTime(), exportSelector.ExportKindFor(r.Descriptor(), aggregation.SumKind), r.Descriptor().InstrumentKind().Monotonic())
+
+	case aggregation.LastValueKind:
+		lv, ok := agg.(aggregation.LastValue)
+		if !ok {
+			return nil, fmt.Errorf("%w: %T", ErrIncompatibleAgg, agg)
+		}
+		value, tm, err := lv.LastValue()
+		if err != nil {
+			return nil, err
+		}
+		return gaugePoint(r, value, time.Time{}, tm)
+
+	case aggregation.ExactKind:
+		e, ok := agg.(aggregation.Points)
+		if !ok {
+			return nil, fmt.Errorf("%w: %T", ErrIncompatibleAgg, agg)
+		}
+		pts, err := e.Points()
+		if err != nil {
+			return nil, err
+		}
+
+		return gaugeArray(r, pts)
+
+	default:
+		return nil, fmt.Errorf("%w: %T", ErrUnimplementedAgg, agg)
+	}
+}
+
+func gaugeArray(record export.Record, points []aggregation.Point) (*metricpb.Metric, error) {
+	desc := record.Descriptor()
+	labels := record.Labels()
+	m := &metricpb.Metric{
+		Name:        desc.Name(),
+		Description: desc.Description(),
+		Unit:        string(desc.Unit()),
+	}
+
+	pbLabels := stringKeyValues(labels.Iter())
+
+	switch nk := desc.NumberKind(); nk {
+	case number.Int64Kind:
+		var pts []*metricpb.IntDataPoint
+		for _, s := range points {
+			pts = append(pts, &metricpb.IntDataPoint{
+				Labels:            pbLabels,
+				StartTimeUnixNano: toNanos(record.StartTime()),
+				TimeUnixNano:      toNanos(record.EndTime()),
+				Value:             s.Number.CoerceToInt64(nk),
+			})
+		}
+		m.Data = &metricpb.Metric_IntGauge{
+			IntGauge: &metricpb.IntGauge{
+				DataPoints: pts,
+			},
+		}
+
+	case number.Float64Kind:
+		var pts []*metricpb.DoubleDataPoint
+		for _, s := range points {
+			pts = append(pts, &metricpb.DoubleDataPoint{
+				Labels:            pbLabels,
+				StartTimeUnixNano: toNanos(record.StartTime()),
+				TimeUnixNano:      toNanos(record.EndTime()),
+				Value:             s.Number.CoerceToFloat64(nk),
+			})
+		}
+		m.Data = &metricpb.Metric_DoubleGauge{
+			DoubleGauge: &metricpb.DoubleGauge{
+				DataPoints: pts,
+			},
+		}
+
+	default:
+		return nil, fmt.Errorf("%w: %v", ErrUnknownValueType, nk)
+	}
+
+	return m, nil
+}
+
+func gaugePoint(record export.Record, num number.Number, start, end time.Time) (*metricpb.Metric, error) {
+	desc := record.Descriptor()
+	labels := record.Labels()
+
+	m := &metricpb.Metric{
+		Name:        desc.Name(),
+		Description: desc.Description(),
+		Unit:        string(desc.Unit()),
+	}
+
+	switch n := desc.NumberKind(); n {
+	case number.Int64Kind:
+		m.Data = &metricpb.Metric_IntGauge{
+			IntGauge: &metricpb.IntGauge{
+				DataPoints: []*metricpb.IntDataPoint{
+					{
+						Value:             num.CoerceToInt64(n),
+						Labels:            stringKeyValues(labels.Iter()),
+						StartTimeUnixNano: toNanos(start),
+						TimeUnixNano:      toNanos(end),
+					},
+				},
+			},
+		}
+	case number.Float64Kind:
+		m.Data = &metricpb.Metric_DoubleGauge{
+			DoubleGauge: &metricpb.DoubleGauge{
+				DataPoints: []*metricpb.DoubleDataPoint{
+					{
+						Value:             num.CoerceToFloat64(n),
+						Labels:            stringKeyValues(labels.Iter()),
+						StartTimeUnixNano: toNanos(start),
+						TimeUnixNano:      toNanos(end),
+					},
+				},
+			},
+		}
+	default:
+		return nil, fmt.Errorf("%w: %v", ErrUnknownValueType, n)
+	}
+
+	return m, nil
+}
+
+func exportKindToTemporality(ek export.ExportKind) metricpb.AggregationTemporality {
+	switch ek {
+	case export.DeltaExportKind:
+		return metricpb.AggregationTemporality_AGGREGATION_TEMPORALITY_DELTA
+	case export.CumulativeExportKind:
+		return metricpb.AggregationTemporality_AGGREGATION_TEMPORALITY_CUMULATIVE
+	}
+	return metricpb.AggregationTemporality_AGGREGATION_TEMPORALITY_UNSPECIFIED
+}
+
+func sumPoint(record export.Record, num number.Number, start, end time.Time, ek export.ExportKind, monotonic bool) (*metricpb.Metric, error) {
+	desc := record.Descriptor()
+	labels := record.Labels()
+
+	m := &metricpb.Metric{
+		Name:        desc.Name(),
+		Description: desc.Description(),
+		Unit:        string(desc.Unit()),
+	}
+
+	switch n := desc.NumberKind(); n {
+	case number.Int64Kind:
+		m.Data = &metricpb.Metric_IntSum{
+			IntSum: &metricpb.IntSum{
+				IsMonotonic:            monotonic,
+				AggregationTemporality: exportKindToTemporality(ek),
+				DataPoints: []*metricpb.IntDataPoint{
+					{
+						Value:             num.CoerceToInt64(n),
+						Labels:            stringKeyValues(labels.Iter()),
+						StartTimeUnixNano: toNanos(start),
+						TimeUnixNano:      toNanos(end),
+					},
+				},
+			},
+		}
+	case number.Float64Kind:
+		m.Data = &metricpb.Metric_DoubleSum{
+			DoubleSum: &metricpb.DoubleSum{
+				IsMonotonic:            monotonic,
+				AggregationTemporality: exportKindToTemporality(ek),
+				DataPoints: []*metricpb.DoubleDataPoint{
+					{
+						Value:             num.CoerceToFloat64(n),
+						Labels:            stringKeyValues(labels.Iter()),
+						StartTimeUnixNano: toNanos(start),
+						TimeUnixNano:      toNanos(end),
+					},
+				},
+			},
+		}
+	default:
+		return nil, fmt.Errorf("%w: %v", ErrUnknownValueType, n)
+	}
+
+	return m, nil
+}
+
+// minMaxSumCountValue returns the values of the MinMaxSumCount Aggregator
+// as discrete values.
+func minMaxSumCountValues(a aggregation.MinMaxSumCount) (min, max, sum number.Number, count uint64, err error) {
+	if min, err = a.Min(); err != nil {
+		return
+	}
+	if max, err = a.Max(); err != nil {
+		return
+	}
+	if sum, err = a.Sum(); err != nil {
+		return
+	}
+	if count, err = a.Count(); err != nil {
+		return
+	}
+	return
+}
+
+// minMaxSumCount transforms a MinMaxSumCount Aggregator into an OTLP Metric.
+func minMaxSumCount(record export.Record, a aggregation.MinMaxSumCount) (*metricpb.Metric, error) {
+	desc := record.Descriptor()
+	labels := record.Labels()
+	min, max, sum, count, err := minMaxSumCountValues(a)
+	if err != nil {
+		return nil, err
+	}
+
+	m := &metricpb.Metric{
+		Name:        desc.Name(),
+		Description: desc.Description(),
+		Unit:        string(desc.Unit()),
+	}
+
+	buckets := []uint64{min.AsRaw(), max.AsRaw()}
+	bounds := []float64{0.0, 100.0}
+
+	switch n := desc.NumberKind(); n {
+	case number.Int64Kind:
+		m.Data = &metricpb.Metric_IntHistogram{
+			IntHistogram: &metricpb.IntHistogram{
+				DataPoints: []*metricpb.IntHistogramDataPoint{
+					{
+						Sum:               sum.CoerceToInt64(n),
+						Labels:            stringKeyValues(labels.Iter()),
+						StartTimeUnixNano: toNanos(record.StartTime()),
+						TimeUnixNano:      toNanos(record.EndTime()),
+						Count:             uint64(count),
+						BucketCounts:      buckets,
+						ExplicitBounds:    bounds,
+					},
+				},
+			},
+		}
+	case number.Float64Kind:
+		m.Data = &metricpb.Metric_DoubleHistogram{
+			DoubleHistogram: &metricpb.DoubleHistogram{
+				DataPoints: []*metricpb.DoubleHistogramDataPoint{
+					{
+						Sum:               sum.CoerceToFloat64(n),
+						Labels:            stringKeyValues(labels.Iter()),
+						StartTimeUnixNano: toNanos(record.StartTime()),
+						TimeUnixNano:      toNanos(record.EndTime()),
+						Count:             uint64(count),
+						BucketCounts:      buckets,
+						ExplicitBounds:    bounds,
+					},
+				},
+			},
+		}
+	default:
+		return nil, fmt.Errorf("%w: %v", ErrUnknownValueType, n)
+	}
+	return m, nil
+}
+
+func histogramValues(a aggregation.Histogram) (boundaries []float64, counts []uint64, err error) {
+	var buckets aggregation.Buckets
+	if buckets, err = a.Histogram(); err != nil {
+		return
+	}
+	boundaries, counts = buckets.Boundaries, buckets.Counts
+	if len(counts) != len(boundaries)+1 {
+		err = ErrTransforming
+		return
+	}
+	return
+}
+
+// histogram transforms a Histogram Aggregator into an OTLP Metric.
+func histogramPoint(record export.Record, ek export.ExportKind, a aggregation.Histogram) (*metricpb.Metric, error) {
+	desc := record.Descriptor()
+	labels := record.Labels()
+	boundaries, counts, err := histogramValues(a)
+	if err != nil {
+		return nil, err
+	}
+
+	count, err := a.Count()
+	if err != nil {
+		return nil, err
+	}
+
+	sum, err := a.Sum()
+	if err != nil {
+		return nil, err
+	}
+
+	m := &metricpb.Metric{
+		Name:        desc.Name(),
+		Description: desc.Description(),
+		Unit:        string(desc.Unit()),
+	}
+	switch n := desc.NumberKind(); n {
+	case number.Int64Kind:
+		m.Data = &metricpb.Metric_IntHistogram{
+			IntHistogram: &metricpb.IntHistogram{
+				AggregationTemporality: exportKindToTemporality(ek),
+				DataPoints: []*metricpb.IntHistogramDataPoint{
+					{
+						Sum:               sum.CoerceToInt64(n),
+						Labels:            stringKeyValues(labels.Iter()),
+						StartTimeUnixNano: toNanos(record.StartTime()),
+						TimeUnixNano:      toNanos(record.EndTime()),
+						Count:             uint64(count),
+						BucketCounts:      counts,
+						ExplicitBounds:    boundaries,
+					},
+				},
+			},
+		}
+	case number.Float64Kind:
+		m.Data = &metricpb.Metric_DoubleHistogram{
+			DoubleHistogram: &metricpb.DoubleHistogram{
+				AggregationTemporality: exportKindToTemporality(ek),
+				DataPoints: []*metricpb.DoubleHistogramDataPoint{
+					{
+						Sum:               sum.CoerceToFloat64(n),
+						Labels:            stringKeyValues(labels.Iter()),
+						StartTimeUnixNano: toNanos(record.StartTime()),
+						TimeUnixNano:      toNanos(record.EndTime()),
+						Count:             uint64(count),
+						BucketCounts:      counts,
+						ExplicitBounds:    boundaries,
+					},
+				},
+			},
+		}
+	default:
+		return nil, fmt.Errorf("%w: %v", ErrUnknownValueType, n)
+	}
+
+	return m, nil
+}
+
+// stringKeyValues transforms a label iterator into an OTLP StringKeyValues.
+func stringKeyValues(iter attribute.Iterator) []*commonpb.StringKeyValue {
+	l := iter.Len()
+	if l == 0 {
+		return nil
+	}
+	result := make([]*commonpb.StringKeyValue, 0, l)
+	for iter.Next() {
+		kv := iter.Label()
+		result = append(result, &commonpb.StringKeyValue{
+			Key:   string(kv.Key),
+			Value: kv.Value.Emit(),
+		})
+	}
+	return result
+}

vendor/go.opentelemetry.io/otel/exporters/otlp/internal/transform/resource.go

@@ -0,0 +1,29 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package transform
+
+import (
+	resourcepb "go.opentelemetry.io/proto/otlp/resource/v1"
+
+	"go.opentelemetry.io/otel/sdk/resource"
+)
+
+// Resource transforms a Resource into an OTLP Resource.
+func Resource(r *resource.Resource) *resourcepb.Resource {
+	if r == nil {
+		return nil
+	}
+	return &resourcepb.Resource{Attributes: ResourceAttributes(r)}
+}

vendor/go.opentelemetry.io/otel/exporters/otlp/internal/transform/span.go

@@ -0,0 +1,218 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package transform
+
+import (
+	"go.opentelemetry.io/otel/attribute"
+	"go.opentelemetry.io/otel/codes"
+	tracepb "go.opentelemetry.io/proto/otlp/trace/v1"
+
+	"go.opentelemetry.io/otel/sdk/instrumentation"
+	tracesdk "go.opentelemetry.io/otel/sdk/trace"
+	"go.opentelemetry.io/otel/trace"
+)
+
+const (
+	maxMessageEventsPerSpan = 128
+)
+
+// SpanData transforms a slice of SpanSnapshot into a slice of OTLP
+// ResourceSpans.
+func SpanData(sdl []*tracesdk.SpanSnapshot) []*tracepb.ResourceSpans {
+	if len(sdl) == 0 {
+		return nil
+	}
+
+	rsm := make(map[attribute.Distinct]*tracepb.ResourceSpans)
+
+	type ilsKey struct {
+		r  attribute.Distinct
+		il instrumentation.Library
+	}
+	ilsm := make(map[ilsKey]*tracepb.InstrumentationLibrarySpans)
+
+	var resources int
+	for _, sd := range sdl {
+		if sd == nil {
+			continue
+		}
+
+		rKey := sd.Resource.Equivalent()
+		iKey := ilsKey{
+			r:  rKey,
+			il: sd.InstrumentationLibrary,
+		}
+		ils, iOk := ilsm[iKey]
+		if !iOk {
+			// Either the resource or instrumentation library were unknown.
+			ils = &tracepb.InstrumentationLibrarySpans{
+				InstrumentationLibrary: instrumentationLibrary(sd.InstrumentationLibrary),
+				Spans:                  []*tracepb.Span{},
+			}
+		}
+		ils.Spans = append(ils.Spans, span(sd))
+		ilsm[iKey] = ils
+
+		rs, rOk := rsm[rKey]
+		if !rOk {
+			resources++
+			// The resource was unknown.
+			rs = &tracepb.ResourceSpans{
+				Resource:                    Resource(sd.Resource),
+				InstrumentationLibrarySpans: []*tracepb.InstrumentationLibrarySpans{ils},
+			}
+			rsm[rKey] = rs
+			continue
+		}
+
+		// The resource has been seen before. Check if the instrumentation
+		// library lookup was unknown because if so we need to add it to the
+		// ResourceSpans. Otherwise, the instrumentation library has already
+		// been seen and the append we did above will be included it in the
+		// InstrumentationLibrarySpans reference.
+		if !iOk {
+			rs.InstrumentationLibrarySpans = append(rs.InstrumentationLibrarySpans, ils)
+		}
+	}
+
+	// Transform the categorized map into a slice
+	rss := make([]*tracepb.ResourceSpans, 0, resources)
+	for _, rs := range rsm {
+		rss = append(rss, rs)
+	}
+	return rss
+}
+
+// span transforms a Span into an OTLP span.
+func span(sd *tracesdk.SpanSnapshot) *tracepb.Span {
+	if sd == nil {
+		return nil
+	}
+
+	tid := sd.SpanContext.TraceID()
+	sid := sd.SpanContext.SpanID()
+
+	s := &tracepb.Span{
+		TraceId:                tid[:],
+		SpanId:                 sid[:],
+		TraceState:             sd.SpanContext.TraceState().String(),
+		Status:                 status(sd.StatusCode, sd.StatusMessage),
+		StartTimeUnixNano:      uint64(sd.StartTime.UnixNano()),
+		EndTimeUnixNano:        uint64(sd.EndTime.UnixNano()),
+		Links:                  links(sd.Links),
+		Kind:                   spanKind(sd.SpanKind),
+		Name:                   sd.Name,
+		Attributes:             Attributes(sd.Attributes),
+		Events:                 spanEvents(sd.MessageEvents),
+		DroppedAttributesCount: uint32(sd.DroppedAttributeCount),
+		DroppedEventsCount:     uint32(sd.DroppedMessageEventCount),
+		DroppedLinksCount:      uint32(sd.DroppedLinkCount),
+	}
+
+	if psid := sd.Parent.SpanID(); psid.IsValid() {
+		s.ParentSpanId = psid[:]
+	}
+
+	return s
+}
+
+// status transform a span code and message into an OTLP span status.
+func status(status codes.Code, message string) *tracepb.Status {
+	var c tracepb.Status_StatusCode
+	switch status {
+	case codes.Error:
+		c = tracepb.Status_STATUS_CODE_ERROR
+	default:
+		c = tracepb.Status_STATUS_CODE_OK
+	}
+	return &tracepb.Status{
+		Code:    c,
+		Message: message,
+	}
+}
+
+// links transforms span Links to OTLP span links.
+func links(links []trace.Link) []*tracepb.Span_Link {
+	if len(links) == 0 {
+		return nil
+	}
+
+	sl := make([]*tracepb.Span_Link, 0, len(links))
+	for _, otLink := range links {
+		// This redefinition is necessary to prevent otLink.*ID[:] copies
+		// being reused -- in short we need a new otLink per iteration.
+		otLink := otLink
+
+		tid := otLink.TraceID()
+		sid := otLink.SpanID()
+
+		sl = append(sl, &tracepb.Span_Link{
+			TraceId:    tid[:],
+			SpanId:     sid[:],
+			Attributes: Attributes(otLink.Attributes),
+		})
+	}
+	return sl
+}
+
+// spanEvents transforms span Events to an OTLP span events.
+func spanEvents(es []trace.Event) []*tracepb.Span_Event {
+	if len(es) == 0 {
+		return nil
+	}
+
+	evCount := len(es)
+	if evCount > maxMessageEventsPerSpan {
+		evCount = maxMessageEventsPerSpan
+	}
+	events := make([]*tracepb.Span_Event, 0, evCount)
+	messageEvents := 0
+
+	// Transform message events
+	for _, e := range es {
+		if messageEvents >= maxMessageEventsPerSpan {
+			break
+		}
+		messageEvents++
+		events = append(events,
+			&tracepb.Span_Event{
+				Name:         e.Name,
+				TimeUnixNano: uint64(e.Time.UnixNano()),
+				Attributes:   Attributes(e.Attributes),
+				// TODO (rghetia) : Add Drop Counts when supported.
+			},
+		)
+	}
+
+	return events
+}
+
+// spanKind transforms a SpanKind to an OTLP span kind.
+func spanKind(kind trace.SpanKind) tracepb.Span_SpanKind {
+	switch kind {
+	case trace.SpanKindInternal:
+		return tracepb.Span_SPAN_KIND_INTERNAL
+	case trace.SpanKindClient:
+		return tracepb.Span_SPAN_KIND_CLIENT
+	case trace.SpanKindServer:
+		return tracepb.Span_SPAN_KIND_SERVER
+	case trace.SpanKindProducer:
+		return tracepb.Span_SPAN_KIND_PRODUCER
+	case trace.SpanKindConsumer:
+		return tracepb.Span_SPAN_KIND_CONSUMER
+	default:
+		return tracepb.Span_SPAN_KIND_UNSPECIFIED
+	}
+}

vendor/go.opentelemetry.io/otel/exporters/otlp/options.go

@@ -0,0 +1,45 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package otlp // import "go.opentelemetry.io/otel/exporters/otlp"
+
+import (
+	metricsdk "go.opentelemetry.io/otel/sdk/export/metric"
+)
+
+const (
+	// DefaultCollectorPort is the port the Exporter will attempt connect to
+	// if no collector port is provided.
+	DefaultCollectorPort uint16 = 4317
+	// DefaultCollectorHost is the host address the Exporter will attempt
+	// connect to if no collector address is provided.
+	DefaultCollectorHost string = "localhost"
+)
+
+// ExporterOption are setting options passed to an Exporter on creation.
+type ExporterOption func(*config)
+
+type config struct {
+	exportKindSelector metricsdk.ExportKindSelector
+}
+
+// WithMetricExportKindSelector defines the ExportKindSelector used
+// for selecting AggregationTemporality (i.e., Cumulative vs. Delta
+// aggregation). If not specified otherwise, exporter will use a
+// cumulative export kind selector.
+func WithMetricExportKindSelector(selector metricsdk.ExportKindSelector) ExporterOption {
+	return func(cfg *config) {
+		cfg.exportKindSelector = selector
+	}
+}

vendor/go.opentelemetry.io/otel/exporters/otlp/optiontypes.go

@@ -0,0 +1,38 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package otlp // import "go.opentelemetry.io/otel/exporters/otlp"
+
+// Compression describes the compression used for payloads sent to the
+// collector.
+type Compression int
+
+const (
+	// NoCompression tells the driver to send payloads without
+	// compression.
+	NoCompression Compression = iota
+	// GzipCompression tells the driver to send payloads after
+	// compressing them with gzip.
+	GzipCompression
+)
+
+// Marshaler describes the kind of message format sent to the collector
+type Marshaler int
+
+const (
+	// MarshalProto tells the driver to send using the protobuf binary format.
+	MarshalProto Marshaler = iota
+	// MarshalJSON tells the driver to send using json format.
+	MarshalJSON
+)

vendor/go.opentelemetry.io/otel/exporters/otlp/otlp.go

@@ -0,0 +1,179 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package otlp // import "go.opentelemetry.io/otel/exporters/otlp"
+
+import (
+	"context"
+	"errors"
+	"sync"
+
+	"go.opentelemetry.io/otel"
+	"go.opentelemetry.io/otel/metric"
+	metricsdk "go.opentelemetry.io/otel/sdk/export/metric"
+	"go.opentelemetry.io/otel/sdk/export/metric/aggregation"
+	"go.opentelemetry.io/otel/sdk/metric/selector/simple"
+	sdktrace "go.opentelemetry.io/otel/sdk/trace"
+
+	"go.opentelemetry.io/otel/sdk/metric/controller/basic"
+	processor "go.opentelemetry.io/otel/sdk/metric/processor/basic"
+	tracesdk "go.opentelemetry.io/otel/sdk/trace"
+)
+
+// Exporter is an OpenTelemetry exporter. It exports both traces and metrics
+// from OpenTelemetry instrumented to code using OpenTelemetry protocol
+// buffers to a configurable receiver.
+type Exporter struct {
+	cfg    config
+	driver ProtocolDriver
+
+	mu      sync.RWMutex
+	started bool
+
+	startOnce sync.Once
+	stopOnce  sync.Once
+}
+
+var _ tracesdk.SpanExporter = (*Exporter)(nil)
+var _ metricsdk.Exporter = (*Exporter)(nil)
+
+// NewExporter constructs a new Exporter and starts it.
+func NewExporter(ctx context.Context, driver ProtocolDriver, opts ...ExporterOption) (*Exporter, error) {
+	exp := NewUnstartedExporter(driver, opts...)
+	if err := exp.Start(ctx); err != nil {
+		return nil, err
+	}
+	return exp, nil
+}
+
+// NewUnstartedExporter constructs a new Exporter and does not start it.
+func NewUnstartedExporter(driver ProtocolDriver, opts ...ExporterOption) *Exporter {
+	cfg := config{
+		// Note: the default ExportKindSelector is specified
+		// as Cumulative:
+		// https://github.com/open-telemetry/opentelemetry-specification/issues/731
+		exportKindSelector: metricsdk.CumulativeExportKindSelector(),
+	}
+	for _, opt := range opts {
+		opt(&cfg)
+	}
+	return &Exporter{
+		cfg:    cfg,
+		driver: driver,
+	}
+}
+
+var (
+	errAlreadyStarted = errors.New("already started")
+)
+
+// Start establishes connections to the OpenTelemetry collector. Starting an
+// already started exporter returns an error.
+func (e *Exporter) Start(ctx context.Context) error {
+	var err = errAlreadyStarted
+	e.startOnce.Do(func() {
+		e.mu.Lock()
+		e.started = true
+		e.mu.Unlock()
+		err = e.driver.Start(ctx)
+	})
+
+	return err
+}
+
+// Shutdown closes all connections and releases resources currently being used
+// by the exporter. If the exporter is not started this does nothing. A shut
+// down exporter can't be started again. Shutting down an already shut down
+// exporter does nothing.
+func (e *Exporter) Shutdown(ctx context.Context) error {
+	e.mu.RLock()
+	started := e.started
+	e.mu.RUnlock()
+
+	if !started {
+		return nil
+	}
+
+	var err error
+
+	e.stopOnce.Do(func() {
+		err = e.driver.Stop(ctx)
+		e.mu.Lock()
+		e.started = false
+		e.mu.Unlock()
+	})
+
+	return err
+}
+
+// Export transforms and batches metric Records into OTLP Metrics and
+// transmits them to the configured collector.
+func (e *Exporter) Export(parent context.Context, cps metricsdk.CheckpointSet) error {
+	return e.driver.ExportMetrics(parent, cps, e.cfg.exportKindSelector)
+}
+
+// ExportKindFor reports back to the OpenTelemetry SDK sending this Exporter
+// metric telemetry that it needs to be provided in a configured format.
+func (e *Exporter) ExportKindFor(desc *metric.Descriptor, kind aggregation.Kind) metricsdk.ExportKind {
+	return e.cfg.exportKindSelector.ExportKindFor(desc, kind)
+}
+
+// ExportSpans transforms and batches trace SpanSnapshots into OTLP Trace and
+// transmits them to the configured collector.
+func (e *Exporter) ExportSpans(ctx context.Context, ss []*tracesdk.SpanSnapshot) error {
+	return e.driver.ExportTraces(ctx, ss)
+}
+
+// NewExportPipeline sets up a complete export pipeline
+// with the recommended TracerProvider setup.
+func NewExportPipeline(ctx context.Context, driver ProtocolDriver, exporterOpts ...ExporterOption) (*Exporter,
+	*sdktrace.TracerProvider, *basic.Controller, error) {
+
+	exp, err := NewExporter(ctx, driver, exporterOpts...)
+	if err != nil {
+		return nil, nil, nil, err
+	}
+
+	tracerProvider := sdktrace.NewTracerProvider(
+		sdktrace.WithBatcher(exp),
+	)
+
+	cntr := basic.New(
+		processor.New(
+			simple.NewWithInexpensiveDistribution(),
+			exp,
+		),
+	)
+
+	return exp, tracerProvider, cntr, nil
+}
+
+// InstallNewPipeline instantiates a NewExportPipeline with the
+// recommended configuration and registers it globally.
+func InstallNewPipeline(ctx context.Context, driver ProtocolDriver, exporterOpts ...ExporterOption) (*Exporter,
+	*sdktrace.TracerProvider, *basic.Controller, error) {
+
+	exp, tp, cntr, err := NewExportPipeline(ctx, driver, exporterOpts...)
+	if err != nil {
+		return nil, nil, nil, err
+	}
+
+	otel.SetTracerProvider(tp)
+	err = cntr.Start(ctx)
+	if err != nil {
+		return nil, nil, nil, err
+	}
+
+	return exp, tp, cntr, err
+}

vendor/go.opentelemetry.io/otel/exporters/otlp/otlpgrpc/connection.go

@@ -0,0 +1,278 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package otlpgrpc
+
+import (
+	"context"
+	"math/rand"
+	"sync"
+	"sync/atomic"
+	"time"
+	"unsafe"
+
+	"google.golang.org/grpc/encoding/gzip"
+
+	"go.opentelemetry.io/otel/exporters/otlp"
+	"go.opentelemetry.io/otel/exporters/otlp/internal/otlpconfig"
+
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/metadata"
+)
+
+type connection struct {
+	// Ensure pointer is 64-bit aligned for atomic operations on both 32 and 64 bit machines.
+	lastConnectErrPtr unsafe.Pointer
+
+	// mu protects the connection as it is accessed by the
+	// exporter goroutines and background connection goroutine
+	mu sync.Mutex
+	cc *grpc.ClientConn
+
+	// these fields are read-only after constructor is finished
+	cfg                  otlpconfig.Config
+	sCfg                 otlpconfig.SignalConfig
+	metadata             metadata.MD
+	newConnectionHandler func(cc *grpc.ClientConn)
+
+	// these channels are created once
+	disconnectedCh             chan bool
+	backgroundConnectionDoneCh chan struct{}
+	stopCh                     chan struct{}
+
+	// this is for tests, so they can replace the closing
+	// routine without a worry of modifying some global variable
+	// or changing it back to original after the test is done
+	closeBackgroundConnectionDoneCh func(ch chan struct{})
+}
+
+func newConnection(cfg otlpconfig.Config, sCfg otlpconfig.SignalConfig, handler func(cc *grpc.ClientConn)) *connection {
+	c := new(connection)
+	c.newConnectionHandler = handler
+	c.cfg = cfg
+	c.sCfg = sCfg
+	if len(c.sCfg.Headers) > 0 {
+		c.metadata = metadata.New(c.sCfg.Headers)
+	}
+	c.closeBackgroundConnectionDoneCh = func(ch chan struct{}) {
+		close(ch)
+	}
+	return c
+}
+
+func (c *connection) startConnection(ctx context.Context) {
+	c.stopCh = make(chan struct{})
+	c.disconnectedCh = make(chan bool, 1)
+	c.backgroundConnectionDoneCh = make(chan struct{})
+
+	if err := c.connect(ctx); err == nil {
+		c.setStateConnected()
+	} else {
+		c.setStateDisconnected(err)
+	}
+	go c.indefiniteBackgroundConnection()
+}
+
+func (c *connection) lastConnectError() error {
+	errPtr := (*error)(atomic.LoadPointer(&c.lastConnectErrPtr))
+	if errPtr == nil {
+		return nil
+	}
+	return *errPtr
+}
+
+func (c *connection) saveLastConnectError(err error) {
+	var errPtr *error
+	if err != nil {
+		errPtr = &err
+	}
+	atomic.StorePointer(&c.lastConnectErrPtr, unsafe.Pointer(errPtr))
+}
+
+func (c *connection) setStateDisconnected(err error) {
+	c.saveLastConnectError(err)
+	select {
+	case c.disconnectedCh <- true:
+	default:
+	}
+	c.newConnectionHandler(nil)
+}
+
+func (c *connection) setStateConnected() {
+	c.saveLastConnectError(nil)
+}
+
+func (c *connection) connected() bool {
+	return c.lastConnectError() == nil
+}
+
+const defaultConnReattemptPeriod = 10 * time.Second
+
+func (c *connection) indefiniteBackgroundConnection() {
+	defer func() {
+		c.closeBackgroundConnectionDoneCh(c.backgroundConnectionDoneCh)
+	}()
+
+	connReattemptPeriod := c.cfg.ReconnectionPeriod
+	if connReattemptPeriod <= 0 {
+		connReattemptPeriod = defaultConnReattemptPeriod
+	}
+
+	// No strong seeding required, nano time can
+	// already help with pseudo uniqueness.
+	rng := rand.New(rand.NewSource(time.Now().UnixNano() + rand.Int63n(1024)))
+
+	// maxJitterNanos: 70% of the connectionReattemptPeriod
+	maxJitterNanos := int64(0.7 * float64(connReattemptPeriod))
+
+	for {
+		// Otherwise these will be the normal scenarios to enable
+		// reconnection if we trip out.
+		// 1. If we've stopped, return entirely
+		// 2. Otherwise block until we are disconnected, and
+		//    then retry connecting
+		select {
+		case <-c.stopCh:
+			return
+
+		case <-c.disconnectedCh:
+			// Quickly check if we haven't stopped at the
+			// same time.
+			select {
+			case <-c.stopCh:
+				return
+
+			default:
+			}
+
+			// Normal scenario that we'll wait for
+		}
+
+		if err := c.connect(context.Background()); err == nil {
+			c.setStateConnected()
+		} else {
+			// this code is unreachable in most cases
+			// c.connect does not establish connection
+			c.setStateDisconnected(err)
+		}
+
+		// Apply some jitter to avoid lockstep retrials of other
+		// collector-exporters. Lockstep retrials could result in an
+		// innocent DDOS, by clogging the machine's resources and network.
+		jitter := time.Duration(rng.Int63n(maxJitterNanos))
+		select {
+		case <-c.stopCh:
+			return
+		case <-time.After(connReattemptPeriod + jitter):
+		}
+	}
+}
+
+func (c *connection) connect(ctx context.Context) error {
+	cc, err := c.dialToCollector(ctx)
+	if err != nil {
+		return err
+	}
+	c.setConnection(cc)
+	c.newConnectionHandler(cc)
+	return nil
+}
+
+// setConnection sets cc as the client connection and returns true if
+// the connection state changed.
+func (c *connection) setConnection(cc *grpc.ClientConn) bool {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+
+	// If previous clientConn is same as the current then just return.
+	// This doesn't happen right now as this func is only called with new ClientConn.
+	// It is more about future-proofing.
+	if c.cc == cc {
+		return false
+	}
+
+	// If the previous clientConn was non-nil, close it
+	if c.cc != nil {
+		_ = c.cc.Close()
+	}
+	c.cc = cc
+	return true
+}
+
+func (c *connection) dialToCollector(ctx context.Context) (*grpc.ClientConn, error) {
+	dialOpts := []grpc.DialOption{}
+	if c.cfg.ServiceConfig != "" {
+		dialOpts = append(dialOpts, grpc.WithDefaultServiceConfig(c.cfg.ServiceConfig))
+	}
+	if c.sCfg.GRPCCredentials != nil {
+		dialOpts = append(dialOpts, grpc.WithTransportCredentials(c.sCfg.GRPCCredentials))
+	} else if c.sCfg.Insecure {
+		dialOpts = append(dialOpts, grpc.WithInsecure())
+	}
+	if c.sCfg.Compression == otlp.GzipCompression {
+		dialOpts = append(dialOpts, grpc.WithDefaultCallOptions(grpc.UseCompressor(gzip.Name)))
+	}
+	if len(c.cfg.DialOptions) != 0 {
+		dialOpts = append(dialOpts, c.cfg.DialOptions...)
+	}
+
+	ctx, cancel := c.contextWithStop(ctx)
+	defer cancel()
+	ctx = c.contextWithMetadata(ctx)
+	return grpc.DialContext(ctx, c.sCfg.Endpoint, dialOpts...)
+}
+
+func (c *connection) contextWithMetadata(ctx context.Context) context.Context {
+	if c.metadata.Len() > 0 {
+		return metadata.NewOutgoingContext(ctx, c.metadata)
+	}
+	return ctx
+}
+
+func (c *connection) shutdown(ctx context.Context) error {
+	close(c.stopCh)
+	// Ensure that the backgroundConnector returns
+	select {
+	case <-c.backgroundConnectionDoneCh:
+	case <-ctx.Done():
+		return ctx.Err()
+	}
+
+	c.mu.Lock()
+	cc := c.cc
+	c.cc = nil
+	c.mu.Unlock()
+
+	if cc != nil {
+		return cc.Close()
+	}
+
+	return nil
+}
+
+func (c *connection) contextWithStop(ctx context.Context) (context.Context, context.CancelFunc) {
+	// Unify the parent context Done signal with the connection's
+	// stop channel.
+	ctx, cancel := context.WithCancel(ctx)
+	go func(ctx context.Context, cancel context.CancelFunc) {
+		select {
+		case <-ctx.Done():
+			// Nothing to do, either cancelled or deadline
+			// happened.
+		case <-c.stopCh:
+			cancel()
+		}
+	}(ctx, cancel)
+	return ctx, cancel
+}

vendor/go.opentelemetry.io/otel/exporters/otlp/otlpgrpc/doc.go

@@ -0,0 +1,25 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+/*
+Package otlpgrpc provides an implementation of otlp.ProtocolDriver
+that connects to the collector and sends traces and metrics using
+gRPC.
+
+This package is currently in a pre-GA phase. Backwards incompatible
+changes may be introduced in subsequent minor version releases as we
+work to track the evolving OpenTelemetry specification and user
+feedback.
+*/
+package otlpgrpc // import "go.opentelemetry.io/otel/exporters/otlp/otlpgrpc"

vendor/go.opentelemetry.io/otel/exporters/otlp/otlpgrpc/driver.go

@@ -0,0 +1,195 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package otlpgrpc // import "go.opentelemetry.io/otel/exporters/otlp/otlpgrpc"
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"sync"
+
+	"go.opentelemetry.io/otel/exporters/otlp/internal/otlpconfig"
+
+	"google.golang.org/grpc"
+
+	"go.opentelemetry.io/otel/exporters/otlp"
+	"go.opentelemetry.io/otel/exporters/otlp/internal/transform"
+	metricsdk "go.opentelemetry.io/otel/sdk/export/metric"
+	tracesdk "go.opentelemetry.io/otel/sdk/trace"
+	colmetricpb "go.opentelemetry.io/proto/otlp/collector/metrics/v1"
+	coltracepb "go.opentelemetry.io/proto/otlp/collector/trace/v1"
+	metricpb "go.opentelemetry.io/proto/otlp/metrics/v1"
+	tracepb "go.opentelemetry.io/proto/otlp/trace/v1"
+)
+
+type driver struct {
+	metricsDriver metricsDriver
+	tracesDriver  tracesDriver
+}
+
+type metricsDriver struct {
+	connection *connection
+
+	lock          sync.Mutex
+	metricsClient colmetricpb.MetricsServiceClient
+}
+
+type tracesDriver struct {
+	connection *connection
+
+	lock         sync.Mutex
+	tracesClient coltracepb.TraceServiceClient
+}
+
+var (
+	errNoClient = errors.New("no client")
+)
+
+// NewDriver creates a new gRPC protocol driver.
+func NewDriver(opts ...Option) otlp.ProtocolDriver {
+	cfg := otlpconfig.NewDefaultConfig()
+	otlpconfig.ApplyGRPCEnvConfigs(&cfg)
+	for _, opt := range opts {
+		opt.ApplyGRPCOption(&cfg)
+	}
+
+	d := &driver{}
+
+	d.tracesDriver = tracesDriver{
+		connection: newConnection(cfg, cfg.Traces, d.tracesDriver.handleNewConnection),
+	}
+
+	d.metricsDriver = metricsDriver{
+		connection: newConnection(cfg, cfg.Metrics, d.metricsDriver.handleNewConnection),
+	}
+	return d
+}
+
+func (md *metricsDriver) handleNewConnection(cc *grpc.ClientConn) {
+	md.lock.Lock()
+	defer md.lock.Unlock()
+	if cc != nil {
+		md.metricsClient = colmetricpb.NewMetricsServiceClient(cc)
+	} else {
+		md.metricsClient = nil
+	}
+}
+
+func (td *tracesDriver) handleNewConnection(cc *grpc.ClientConn) {
+	td.lock.Lock()
+	defer td.lock.Unlock()
+	if cc != nil {
+		td.tracesClient = coltracepb.NewTraceServiceClient(cc)
+	} else {
+		td.tracesClient = nil
+	}
+}
+
+// Start implements otlp.ProtocolDriver. It establishes a connection
+// to the collector.
+func (d *driver) Start(ctx context.Context) error {
+	d.tracesDriver.connection.startConnection(ctx)
+	d.metricsDriver.connection.startConnection(ctx)
+	return nil
+}
+
+// Stop implements otlp.ProtocolDriver. It shuts down the connection
+// to the collector.
+func (d *driver) Stop(ctx context.Context) error {
+	if err := d.tracesDriver.connection.shutdown(ctx); err != nil {
+		return err
+	}
+
+	return d.metricsDriver.connection.shutdown(ctx)
+}
+
+// ExportMetrics implements otlp.ProtocolDriver. It transforms metrics
+// to protobuf binary format and sends the result to the collector.
+func (d *driver) ExportMetrics(ctx context.Context, cps metricsdk.CheckpointSet, selector metricsdk.ExportKindSelector) error {
+	if !d.metricsDriver.connection.connected() {
+		return fmt.Errorf("metrics exporter is disconnected from the server %s: %w", d.metricsDriver.connection.sCfg.Endpoint, d.metricsDriver.connection.lastConnectError())
+	}
+	ctx, cancel := d.metricsDriver.connection.contextWithStop(ctx)
+	defer cancel()
+	ctx, tCancel := context.WithTimeout(ctx, d.metricsDriver.connection.sCfg.Timeout)
+	defer tCancel()
+
+	rms, err := transform.CheckpointSet(ctx, selector, cps, 1)
+	if err != nil {
+		return err
+	}
+	if len(rms) == 0 {
+		return nil
+	}
+
+	return d.metricsDriver.uploadMetrics(ctx, rms)
+}
+
+func (md *metricsDriver) uploadMetrics(ctx context.Context, protoMetrics []*metricpb.ResourceMetrics) error {
+	ctx = md.connection.contextWithMetadata(ctx)
+	err := func() error {
+		md.lock.Lock()
+		defer md.lock.Unlock()
+		if md.metricsClient == nil {
+			return errNoClient
+		}
+		_, err := md.metricsClient.Export(ctx, &colmetricpb.ExportMetricsServiceRequest{
+			ResourceMetrics: protoMetrics,
+		})
+		return err
+	}()
+	if err != nil {
+		md.connection.setStateDisconnected(err)
+	}
+	return err
+}
+
+// ExportTraces implements otlp.ProtocolDriver. It transforms spans to
+// protobuf binary format and sends the result to the collector.
+func (d *driver) ExportTraces(ctx context.Context, ss []*tracesdk.SpanSnapshot) error {
+	if !d.tracesDriver.connection.connected() {
+		return fmt.Errorf("traces exporter is disconnected from the server %s: %w", d.tracesDriver.connection.sCfg.Endpoint, d.tracesDriver.connection.lastConnectError())
+	}
+	ctx, cancel := d.tracesDriver.connection.contextWithStop(ctx)
+	defer cancel()
+	ctx, tCancel := context.WithTimeout(ctx, d.tracesDriver.connection.sCfg.Timeout)
+	defer tCancel()
+
+	protoSpans := transform.SpanData(ss)
+	if len(protoSpans) == 0 {
+		return nil
+	}
+
+	return d.tracesDriver.uploadTraces(ctx, protoSpans)
+}
+
+func (td *tracesDriver) uploadTraces(ctx context.Context, protoSpans []*tracepb.ResourceSpans) error {
+	ctx = td.connection.contextWithMetadata(ctx)
+	err := func() error {
+		td.lock.Lock()
+		defer td.lock.Unlock()
+		if td.tracesClient == nil {
+			return errNoClient
+		}
+		_, err := td.tracesClient.Export(ctx, &coltracepb.ExportTraceServiceRequest{
+			ResourceSpans: protoSpans,
+		})
+		return err
+	}()
+	if err != nil {
+		td.connection.setStateDisconnected(err)
+	}
+	return err
+}

vendor/go.opentelemetry.io/otel/exporters/otlp/otlpgrpc/options.go

@@ -0,0 +1,202 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package otlpgrpc
+
+import (
+	"fmt"
+	"time"
+
+	"go.opentelemetry.io/otel"
+	"go.opentelemetry.io/otel/exporters/otlp"
+	"go.opentelemetry.io/otel/exporters/otlp/internal/otlpconfig"
+
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/credentials"
+)
+
+// Option applies an option to the gRPC driver.
+type Option interface {
+	otlpconfig.GRPCOption
+}
+
+// WithInsecure disables client transport security for the exporter's gRPC connection
+// just like grpc.WithInsecure() https://pkg.go.dev/google.golang.org/grpc#WithInsecure
+// does. Note, by default, client security is required unless WithInsecure is used.
+func WithInsecure() Option {
+	return otlpconfig.WithInsecure()
+}
+
+// WithTracesInsecure disables client transport security for the traces exporter's gRPC connection
+// just like grpc.WithInsecure() https://pkg.go.dev/google.golang.org/grpc#WithInsecure
+// does. Note, by default, client security is required unless WithInsecure is used.
+func WithTracesInsecure() Option {
+	return otlpconfig.WithInsecureTraces()
+}
+
+// WithInsecureMetrics disables client transport security for the metrics exporter's gRPC connection
+// just like grpc.WithInsecure() https://pkg.go.dev/google.golang.org/grpc#WithInsecure
+// does. Note, by default, client security is required unless WithInsecure is used.
+func WithInsecureMetrics() Option {
+	return otlpconfig.WithInsecureMetrics()
+}
+
+// WithEndpoint allows one to set the endpoint that the exporter will
+// connect to the collector on. If unset, it will instead try to use
+// connect to DefaultCollectorHost:DefaultCollectorPort.
+func WithEndpoint(endpoint string) Option {
+	return otlpconfig.WithEndpoint(endpoint)
+}
+
+// WithTracesEndpoint allows one to set the traces endpoint that the exporter will
+// connect to the collector on. If unset, it will instead try to use
+// connect to DefaultCollectorHost:DefaultCollectorPort.
+func WithTracesEndpoint(endpoint string) Option {
+	return otlpconfig.WithTracesEndpoint(endpoint)
+}
+
+// WithMetricsEndpoint allows one to set the metrics endpoint that the exporter will
+// connect to the collector on. If unset, it will instead try to use
+// connect to DefaultCollectorHost:DefaultCollectorPort.
+func WithMetricsEndpoint(endpoint string) Option {
+	return otlpconfig.WithMetricsEndpoint(endpoint)
+}
+
+// WithReconnectionPeriod allows one to set the delay between next connection attempt
+// after failing to connect with the collector.
+func WithReconnectionPeriod(rp time.Duration) otlpconfig.GRPCOption {
+	return otlpconfig.NewGRPCOption(func(cfg *otlpconfig.Config) {
+		cfg.ReconnectionPeriod = rp
+	})
+}
+
+func compressorToCompression(compressor string) otlp.Compression {
+	switch compressor {
+	case "gzip":
+		return otlp.GzipCompression
+	}
+
+	otel.Handle(fmt.Errorf("invalid compression type: '%s', using no compression as default", compressor))
+	return otlp.NoCompression
+}
+
+// WithCompressor will set the compressor for the gRPC client to use when sending requests.
+// It is the responsibility of the caller to ensure that the compressor set has been registered
+// with google.golang.org/grpc/encoding. This can be done by encoding.RegisterCompressor. Some
+// compressors auto-register on import, such as gzip, which can be registered by calling
+// `import _ "google.golang.org/grpc/encoding/gzip"`.
+func WithCompressor(compressor string) Option {
+	return otlpconfig.WithCompression(compressorToCompression(compressor))
+}
+
+// WithTracesCompression will set the compressor for the gRPC client to use when sending traces requests.
+// It is the responsibility of the caller to ensure that the compressor set has been registered
+// with google.golang.org/grpc/encoding. This can be done by encoding.RegisterCompressor. Some
+// compressors auto-register on import, such as gzip, which can be registered by calling
+// `import _ "google.golang.org/grpc/encoding/gzip"`.
+func WithTracesCompression(compressor string) Option {
+	return otlpconfig.WithTracesCompression(compressorToCompression(compressor))
+}
+
+// WithMetricsCompression will set the compressor for the gRPC client to use when sending metrics requests.
+// It is the responsibility of the caller to ensure that the compressor set has been registered
+// with google.golang.org/grpc/encoding. This can be done by encoding.RegisterCompressor. Some
+// compressors auto-register on import, such as gzip, which can be registered by calling
+// `import _ "google.golang.org/grpc/encoding/gzip"`.
+func WithMetricsCompression(compressor string) Option {
+	return otlpconfig.WithMetricsCompression(compressorToCompression(compressor))
+}
+
+// WithHeaders will send the provided headers with gRPC requests.
+func WithHeaders(headers map[string]string) Option {
+	return otlpconfig.WithHeaders(headers)
+}
+
+// WithTracesHeaders will send the provided headers with gRPC traces requests.
+func WithTracesHeaders(headers map[string]string) Option {
+	return otlpconfig.WithTracesHeaders(headers)
+}
+
+// WithMetricsHeaders will send the provided headers with gRPC metrics requests.
+func WithMetricsHeaders(headers map[string]string) Option {
+	return otlpconfig.WithMetricsHeaders(headers)
+}
+
+// WithTLSCredentials allows the connection to use TLS credentials
+// when talking to the server. It takes in grpc.TransportCredentials instead
+// of say a Certificate file or a tls.Certificate, because the retrieving of
+// these credentials can be done in many ways e.g. plain file, in code tls.Config
+// or by certificate rotation, so it is up to the caller to decide what to use.
+func WithTLSCredentials(creds credentials.TransportCredentials) Option {
+	return otlpconfig.NewGRPCOption(func(cfg *otlpconfig.Config) {
+		cfg.Traces.GRPCCredentials = creds
+		cfg.Metrics.GRPCCredentials = creds
+	})
+}
+
+// WithTracesTLSCredentials allows the connection to use TLS credentials
+// when talking to the traces server. It takes in grpc.TransportCredentials instead
+// of say a Certificate file or a tls.Certificate, because the retrieving of
+// these credentials can be done in many ways e.g. plain file, in code tls.Config
+// or by certificate rotation, so it is up to the caller to decide what to use.
+func WithTracesTLSCredentials(creds credentials.TransportCredentials) Option {
+	return otlpconfig.NewGRPCOption(func(cfg *otlpconfig.Config) {
+		cfg.Traces.GRPCCredentials = creds
+	})
+}
+
+// WithMetricsTLSCredentials allows the connection to use TLS credentials
+// when talking to the metrics server. It takes in grpc.TransportCredentials instead
+// of say a Certificate file or a tls.Certificate, because the retrieving of
+// these credentials can be done in many ways e.g. plain file, in code tls.Config
+// or by certificate rotation, so it is up to the caller to decide what to use.
+func WithMetricsTLSCredentials(creds credentials.TransportCredentials) Option {
+	return otlpconfig.NewGRPCOption(func(cfg *otlpconfig.Config) {
+		cfg.Metrics.GRPCCredentials = creds
+	})
+}
+
+// WithServiceConfig defines the default gRPC service config used.
+func WithServiceConfig(serviceConfig string) Option {
+	return otlpconfig.NewGRPCOption(func(cfg *otlpconfig.Config) {
+		cfg.ServiceConfig = serviceConfig
+	})
+}
+
+// WithDialOption opens support to any grpc.DialOption to be used. If it conflicts
+// with some other configuration the GRPC specified via the collector the ones here will
+// take preference since they are set last.
+func WithDialOption(opts ...grpc.DialOption) Option {
+	return otlpconfig.NewGRPCOption(func(cfg *otlpconfig.Config) {
+		cfg.DialOptions = opts
+	})
+}
+
+// WithTimeout tells the driver the max waiting time for the backend to process
+// each spans or metrics batch. If unset, the default will be 10 seconds.
+func WithTimeout(duration time.Duration) Option {
+	return otlpconfig.WithTimeout(duration)
+}
+
+// WithTracesTimeout tells the driver the max waiting time for the backend to process
+// each spans batch. If unset, the default will be 10 seconds.
+func WithTracesTimeout(duration time.Duration) Option {
+	return otlpconfig.WithTracesTimeout(duration)
+}
+
+// WithMetricsTimeout tells the driver the max waiting time for the backend to process
+// each metrics batch. If unset, the default will be 10 seconds.
+func WithMetricsTimeout(duration time.Duration) Option {
+	return otlpconfig.WithMetricsTimeout(duration)
+}

vendor/go.opentelemetry.io/otel/exporters/otlp/protocoldriver.go

@@ -0,0 +1,145 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package otlp // import "go.opentelemetry.io/otel/exporters/otlp"
+
+import (
+	"context"
+	"sync"
+
+	metricsdk "go.opentelemetry.io/otel/sdk/export/metric"
+	tracesdk "go.opentelemetry.io/otel/sdk/trace"
+)
+
+// ProtocolDriver is an interface used by OTLP exporter. It's
+// responsible for connecting to and disconnecting from the collector,
+// and for transforming traces and metrics into wire format and
+// transmitting them to the collector.
+type ProtocolDriver interface {
+	// Start should establish connection(s) to endpoint(s). It is
+	// called just once by the exporter, so the implementation
+	// does not need to worry about idempotence and locking.
+	Start(ctx context.Context) error
+	// Stop should close the connections. The function is called
+	// only once by the exporter, so the implementation does not
+	// need to worry about idempotence, but it may be called
+	// concurrently with ExportMetrics or ExportTraces, so proper
+	// locking is required. The function serves as a
+	// synchronization point - after the function returns, the
+	// process of closing connections is assumed to be finished.
+	Stop(ctx context.Context) error
+	// ExportMetrics should transform the passed metrics to the
+	// wire format and send it to the collector. May be called
+	// concurrently with ExportTraces, so the manager needs to
+	// take this into account by doing proper locking.
+	ExportMetrics(ctx context.Context, cps metricsdk.CheckpointSet, selector metricsdk.ExportKindSelector) error
+	// ExportTraces should transform the passed traces to the wire
+	// format and send it to the collector. May be called
+	// concurrently with ExportMetrics, so the manager needs to
+	// take this into account by doing proper locking.
+	ExportTraces(ctx context.Context, ss []*tracesdk.SpanSnapshot) error
+}
+
+// SplitConfig is used to configure a split driver.
+type SplitConfig struct {
+	// ForMetrics driver will be used for sending metrics to the
+	// collector.
+	ForMetrics ProtocolDriver
+	// ForTraces driver will be used for sending spans to the
+	// collector.
+	ForTraces ProtocolDriver
+}
+
+type splitDriver struct {
+	metric ProtocolDriver
+	trace  ProtocolDriver
+}
+
+var _ ProtocolDriver = (*splitDriver)(nil)
+
+// NewSplitDriver creates a protocol driver which contains two other
+// protocol drivers and will forward traces to one of them and metrics
+// to another.
+func NewSplitDriver(cfg SplitConfig) ProtocolDriver {
+	return &splitDriver{
+		metric: cfg.ForMetrics,
+		trace:  cfg.ForTraces,
+	}
+}
+
+// Start implements ProtocolDriver. It starts both drivers at the same
+// time.
+func (d *splitDriver) Start(ctx context.Context) error {
+	wg := sync.WaitGroup{}
+	wg.Add(2)
+	var (
+		metricErr error
+		traceErr  error
+	)
+	go func() {
+		defer wg.Done()
+		metricErr = d.metric.Start(ctx)
+	}()
+	go func() {
+		defer wg.Done()
+		traceErr = d.trace.Start(ctx)
+	}()
+	wg.Wait()
+	if metricErr != nil {
+		return metricErr
+	}
+	if traceErr != nil {
+		return traceErr
+	}
+	return nil
+}
+
+// Stop implements ProtocolDriver. It stops both drivers at the same
+// time.
+func (d *splitDriver) Stop(ctx context.Context) error {
+	wg := sync.WaitGroup{}
+	wg.Add(2)
+	var (
+		metricErr error
+		traceErr  error
+	)
+	go func() {
+		defer wg.Done()
+		metricErr = d.metric.Stop(ctx)
+	}()
+	go func() {
+		defer wg.Done()
+		traceErr = d.trace.Stop(ctx)
+	}()
+	wg.Wait()
+	if metricErr != nil {
+		return metricErr
+	}
+	if traceErr != nil {
+		return traceErr
+	}
+	return nil
+}
+
+// ExportMetrics implements ProtocolDriver. It forwards the call to
+// the driver used for sending metrics.
+func (d *splitDriver) ExportMetrics(ctx context.Context, cps metricsdk.CheckpointSet, selector metricsdk.ExportKindSelector) error {
+	return d.metric.ExportMetrics(ctx, cps, selector)
+}
+
+// ExportTraces implements ProtocolDriver. It forwards the call to the
+// driver used for sending spans.
+func (d *splitDriver) ExportTraces(ctx context.Context, ss []*tracesdk.SpanSnapshot) error {
+	return d.trace.ExportTraces(ctx, ss)
+}

vendor/go.opentelemetry.io/otel/get_main_pkgs.sh

@@ -0,0 +1,41 @@
+#!/usr/bin/env bash
+
+# Copyright The OpenTelemetry Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+set -euo pipefail
+
+top_dir='.'
+if [[ $# -gt 0 ]]; then
+    top_dir="${1}"
+fi
+
+p=$(pwd)
+mod_dirs=()
+
+# Note `mapfile` does not exist in older bash versions:
+# https://stackoverflow.com/questions/41475261/need-alternative-to-readarray-mapfile-for-script-on-older-version-of-bash
+
+while IFS= read -r line; do
+    mod_dirs+=("$line")
+done < <(find "${top_dir}" -type f -name 'go.mod' -exec dirname {} \; | sort)
+
+for mod_dir in "${mod_dirs[@]}"; do
+    cd "${mod_dir}"
+
+    while IFS= read -r line; do
+        echo ".${line#${p}}"
+    done < <(go list --find -f '{{.Name}}|{{.Dir}}' ./... | grep '^main|' | cut -f 2- -d '|')
+    cd "${p}"
+done

vendor/go.opentelemetry.io/otel/go.mod

@@ -0,0 +1,55 @@
+module go.opentelemetry.io/otel
+
+go 1.14
+
+require (
+	github.com/google/go-cmp v0.5.5
+	github.com/stretchr/testify v1.7.0
+	go.opentelemetry.io/otel/metric v0.20.0
+	go.opentelemetry.io/otel/oteltest v0.20.0
+	go.opentelemetry.io/otel/trace v0.20.0
+)
+
+replace go.opentelemetry.io/otel => ./
+
+replace go.opentelemetry.io/otel/bridge/opencensus => ./bridge/opencensus
+
+replace go.opentelemetry.io/otel/bridge/opentracing => ./bridge/opentracing
+
+replace go.opentelemetry.io/otel/example/jaeger => ./example/jaeger
+
+replace go.opentelemetry.io/otel/example/namedtracer => ./example/namedtracer
+
+replace go.opentelemetry.io/otel/example/opencensus => ./example/opencensus
+
+replace go.opentelemetry.io/otel/example/otel-collector => ./example/otel-collector
+
+replace go.opentelemetry.io/otel/example/prom-collector => ./example/prom-collector
+
+replace go.opentelemetry.io/otel/example/prometheus => ./example/prometheus
+
+replace go.opentelemetry.io/otel/example/zipkin => ./example/zipkin
+
+replace go.opentelemetry.io/otel/exporters/metric/prometheus => ./exporters/metric/prometheus
+
+replace go.opentelemetry.io/otel/exporters/otlp => ./exporters/otlp
+
+replace go.opentelemetry.io/otel/exporters/stdout => ./exporters/stdout
+
+replace go.opentelemetry.io/otel/exporters/trace/jaeger => ./exporters/trace/jaeger
+
+replace go.opentelemetry.io/otel/exporters/trace/zipkin => ./exporters/trace/zipkin
+
+replace go.opentelemetry.io/otel/internal/tools => ./internal/tools
+
+replace go.opentelemetry.io/otel/sdk => ./sdk
+
+replace go.opentelemetry.io/otel/metric => ./metric
+
+replace go.opentelemetry.io/otel/oteltest => ./oteltest
+
+replace go.opentelemetry.io/otel/sdk/export/metric => ./sdk/export/metric
+
+replace go.opentelemetry.io/otel/sdk/metric => ./sdk/metric
+
+replace go.opentelemetry.io/otel/trace => ./trace

vendor/go.opentelemetry.io/otel/go.sum

@@ -0,0 +1,15 @@
+github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8=
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/google/go-cmp v0.5.5 h1:Khx7svrCpmxxtHBq5j2mp/xVjsi8hQMfNLvJFAlrGgU=
+github.com/google/go-cmp v0.5.5/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/testify v1.7.0 h1:nwc3DEeHmmLAfoZucVR881uASk0Mfjw8xYJ99tb5CcY=
+github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
+golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543 h1:E7g+9GITq07hpfrRu66IVDexMakfv52eLZ2CXBWiKr4=
+golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c h1:dUUwHk2QECo/6vqA44rthZ8ie2QXMNeKRTHCNY2nXvo=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

vendor/go.opentelemetry.io/otel/handler.go

@@ -0,0 +1,89 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package otel // import "go.opentelemetry.io/otel"
+
+import (
+	"log"
+	"os"
+	"sync"
+	"sync/atomic"
+)
+
+var (
+	// globalErrorHandler provides an ErrorHandler that can be used
+	// throughout an OpenTelemetry instrumented project. When a user
+	// specified ErrorHandler is registered (`SetErrorHandler`) all calls to
+	// `Handle` and will be delegated to the registered ErrorHandler.
+	globalErrorHandler = &loggingErrorHandler{
+		l: log.New(os.Stderr, "", log.LstdFlags),
+	}
+
+	// delegateErrorHandlerOnce ensures that a user provided ErrorHandler is
+	// only ever registered once.
+	delegateErrorHandlerOnce sync.Once
+
+	// Comiple time check that loggingErrorHandler implements ErrorHandler.
+	_ ErrorHandler = (*loggingErrorHandler)(nil)
+)
+
+// loggingErrorHandler logs all errors to STDERR.
+type loggingErrorHandler struct {
+	delegate atomic.Value
+
+	l *log.Logger
+}
+
+// setDelegate sets the ErrorHandler delegate if one is not already set.
+func (h *loggingErrorHandler) setDelegate(d ErrorHandler) {
+	if h.delegate.Load() != nil {
+		// Delegate already registered
+		return
+	}
+	h.delegate.Store(d)
+}
+
+// Handle implements ErrorHandler.
+func (h *loggingErrorHandler) Handle(err error) {
+	if d := h.delegate.Load(); d != nil {
+		d.(ErrorHandler).Handle(err)
+		return
+	}
+	h.l.Print(err)
+}
+
+// GetErrorHandler returns the global ErrorHandler instance. If no ErrorHandler
+// instance has been set (`SetErrorHandler`), the default ErrorHandler which
+// logs errors to STDERR is returned.
+func GetErrorHandler() ErrorHandler {
+	return globalErrorHandler
+}
+
+// SetErrorHandler sets the global ErrorHandler to be h.
+func SetErrorHandler(h ErrorHandler) {
+	delegateErrorHandlerOnce.Do(func() {
+		current := GetErrorHandler()
+		if current == h {
+			return
+		}
+		if internalHandler, ok := current.(*loggingErrorHandler); ok {
+			internalHandler.setDelegate(h)
+		}
+	})
+}
+
+// Handle is a convience function for ErrorHandler().Handle(err)
+func Handle(err error) {
+	GetErrorHandler().Handle(err)
+}

vendor/go.opentelemetry.io/otel/internal/baggage/baggage.go

@@ -0,0 +1,338 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package baggage provides types and functions to manage W3C Baggage.
+package baggage
+
+import (
+	"context"
+
+	"go.opentelemetry.io/otel/attribute"
+)
+
+type rawMap map[attribute.Key]attribute.Value
+type keySet map[attribute.Key]struct{}
+
+// Map is an immutable storage for correlations.
+type Map struct {
+	m rawMap
+}
+
+// MapUpdate contains information about correlation changes to be
+// made.
+type MapUpdate struct {
+	// DropSingleK contains a single key to be dropped from
+	// correlations. Use this to avoid an overhead of a slice
+	// allocation if there is only one key to drop.
+	DropSingleK attribute.Key
+	// DropMultiK contains all the keys to be dropped from
+	// correlations.
+	DropMultiK []attribute.Key
+
+	// SingleKV contains a single key-value pair to be added to
+	// correlations. Use this to avoid an overhead of a slice
+	// allocation if there is only one key-value pair to add.
+	SingleKV attribute.KeyValue
+	// MultiKV contains all the key-value pairs to be added to
+	// correlations.
+	MultiKV []attribute.KeyValue
+}
+
+func newMap(raw rawMap) Map {
+	return Map{
+		m: raw,
+	}
+}
+
+// NewEmptyMap creates an empty correlations map.
+func NewEmptyMap() Map {
+	return newMap(nil)
+}
+
+// NewMap creates a map with the contents of the update applied. In
+// this function, having an update with DropSingleK or DropMultiK
+// makes no sense - those fields are effectively ignored.
+func NewMap(update MapUpdate) Map {
+	return NewEmptyMap().Apply(update)
+}
+
+// Apply creates a copy of the map with the contents of the update
+// applied. Apply will first drop the keys from DropSingleK and
+// DropMultiK, then add key-value pairs from SingleKV and MultiKV.
+func (m Map) Apply(update MapUpdate) Map {
+	delSet, addSet := getModificationSets(update)
+	mapSize := getNewMapSize(m.m, delSet, addSet)
+
+	r := make(rawMap, mapSize)
+	for k, v := range m.m {
+		// do not copy items we want to drop
+		if _, ok := delSet[k]; ok {
+			continue
+		}
+		// do not copy items we would overwrite
+		if _, ok := addSet[k]; ok {
+			continue
+		}
+		r[k] = v
+	}
+	if update.SingleKV.Key.Defined() {
+		r[update.SingleKV.Key] = update.SingleKV.Value
+	}
+	for _, kv := range update.MultiKV {
+		r[kv.Key] = kv.Value
+	}
+	if len(r) == 0 {
+		r = nil
+	}
+	return newMap(r)
+}
+
+func getModificationSets(update MapUpdate) (delSet, addSet keySet) {
+	deletionsCount := len(update.DropMultiK)
+	if update.DropSingleK.Defined() {
+		deletionsCount++
+	}
+	if deletionsCount > 0 {
+		delSet = make(map[attribute.Key]struct{}, deletionsCount)
+		for _, k := range update.DropMultiK {
+			delSet[k] = struct{}{}
+		}
+		if update.DropSingleK.Defined() {
+			delSet[update.DropSingleK] = struct{}{}
+		}
+	}
+
+	additionsCount := len(update.MultiKV)
+	if update.SingleKV.Key.Defined() {
+		additionsCount++
+	}
+	if additionsCount > 0 {
+		addSet = make(map[attribute.Key]struct{}, additionsCount)
+		for _, k := range update.MultiKV {
+			addSet[k.Key] = struct{}{}
+		}
+		if update.SingleKV.Key.Defined() {
+			addSet[update.SingleKV.Key] = struct{}{}
+		}
+	}
+
+	return
+}
+
+func getNewMapSize(m rawMap, delSet, addSet keySet) int {
+	mapSizeDiff := 0
+	for k := range addSet {
+		if _, ok := m[k]; !ok {
+			mapSizeDiff++
+		}
+	}
+	for k := range delSet {
+		if _, ok := m[k]; ok {
+			if _, inAddSet := addSet[k]; !inAddSet {
+				mapSizeDiff--
+			}
+		}
+	}
+	return len(m) + mapSizeDiff
+}
+
+// Value gets a value from correlations map and returns a boolean
+// value indicating whether the key exist in the map.
+func (m Map) Value(k attribute.Key) (attribute.Value, bool) {
+	value, ok := m.m[k]
+	return value, ok
+}
+
+// HasValue returns a boolean value indicating whether the key exist
+// in the map.
+func (m Map) HasValue(k attribute.Key) bool {
+	_, has := m.Value(k)
+	return has
+}
+
+// Len returns a length of the map.
+func (m Map) Len() int {
+	return len(m.m)
+}
+
+// Foreach calls a passed callback once on each key-value pair until
+// all the key-value pairs of the map were iterated or the callback
+// returns false, whichever happens first.
+func (m Map) Foreach(f func(attribute.KeyValue) bool) {
+	for k, v := range m.m {
+		if !f(attribute.KeyValue{
+			Key:   k,
+			Value: v,
+		}) {
+			return
+		}
+	}
+}
+
+type correlationsType struct{}
+
+// SetHookFunc describes a type of a callback that is called when
+// storing baggage in the context.
+type SetHookFunc func(context.Context) context.Context
+
+// GetHookFunc describes a type of a callback that is called when
+// getting baggage from the context.
+type GetHookFunc func(context.Context, Map) Map
+
+// value under this key is either of type Map or correlationsData
+var correlationsKey = &correlationsType{}
+
+type correlationsData struct {
+	m       Map
+	setHook SetHookFunc
+	getHook GetHookFunc
+}
+
+func (d correlationsData) isHookless() bool {
+	return d.setHook == nil && d.getHook == nil
+}
+
+type hookKind int
+
+const (
+	hookKindSet hookKind = iota
+	hookKindGet
+)
+
+func (d *correlationsData) overrideHook(kind hookKind, setHook SetHookFunc, getHook GetHookFunc) {
+	switch kind {
+	case hookKindSet:
+		d.setHook = setHook
+	case hookKindGet:
+		d.getHook = getHook
+	}
+}
+
+// ContextWithSetHook installs a hook function that will be invoked
+// every time ContextWithMap is called. To avoid unnecessary callback
+// invocations (recursive or not), the callback can temporarily clear
+// the hooks from the context with the ContextWithNoHooks function.
+//
+// Note that NewContext also calls ContextWithMap, so the hook will be
+// invoked.
+//
+// Passing nil SetHookFunc creates a context with no set hook to call.
+//
+// This function should not be used by applications or libraries. It
+// is mostly for interoperation with other observability APIs.
+func ContextWithSetHook(ctx context.Context, hook SetHookFunc) context.Context {
+	return contextWithHook(ctx, hookKindSet, hook, nil)
+}
+
+// ContextWithGetHook installs a hook function that will be invoked
+// every time MapFromContext is called. To avoid unnecessary callback
+// invocations (recursive or not), the callback can temporarily clear
+// the hooks from the context with the ContextWithNoHooks function.
+//
+// Note that NewContext also calls MapFromContext, so the hook will be
+// invoked.
+//
+// Passing nil GetHookFunc creates a context with no get hook to call.
+//
+// This function should not be used by applications or libraries. It
+// is mostly for interoperation with other observability APIs.
+func ContextWithGetHook(ctx context.Context, hook GetHookFunc) context.Context {
+	return contextWithHook(ctx, hookKindGet, nil, hook)
+}
+
+func contextWithHook(ctx context.Context, kind hookKind, setHook SetHookFunc, getHook GetHookFunc) context.Context {
+	switch v := ctx.Value(correlationsKey).(type) {
+	case correlationsData:
+		v.overrideHook(kind, setHook, getHook)
+		if v.isHookless() {
+			return context.WithValue(ctx, correlationsKey, v.m)
+		}
+		return context.WithValue(ctx, correlationsKey, v)
+	case Map:
+		return contextWithOneHookAndMap(ctx, kind, setHook, getHook, v)
+	default:
+		m := NewEmptyMap()
+		return contextWithOneHookAndMap(ctx, kind, setHook, getHook, m)
+	}
+}
+
+func contextWithOneHookAndMap(ctx context.Context, kind hookKind, setHook SetHookFunc, getHook GetHookFunc, m Map) context.Context {
+	d := correlationsData{m: m}
+	d.overrideHook(kind, setHook, getHook)
+	if d.isHookless() {
+		return ctx
+	}
+	return context.WithValue(ctx, correlationsKey, d)
+}
+
+// ContextWithNoHooks creates a context with all the hooks
+// disabled. Also returns old set and get hooks. This function can be
+// used to temporarily clear the context from hooks and then reinstate
+// them by calling ContextWithSetHook and ContextWithGetHook functions
+// passing the hooks returned by this function.
+//
+// This function should not be used by applications or libraries. It
+// is mostly for interoperation with other observability APIs.
+func ContextWithNoHooks(ctx context.Context) (context.Context, SetHookFunc, GetHookFunc) {
+	switch v := ctx.Value(correlationsKey).(type) {
+	case correlationsData:
+		return context.WithValue(ctx, correlationsKey, v.m), v.setHook, v.getHook
+	default:
+		return ctx, nil, nil
+	}
+}
+
+// ContextWithMap returns a context with the Map entered into it.
+func ContextWithMap(ctx context.Context, m Map) context.Context {
+	switch v := ctx.Value(correlationsKey).(type) {
+	case correlationsData:
+		v.m = m
+		ctx = context.WithValue(ctx, correlationsKey, v)
+		if v.setHook != nil {
+			ctx = v.setHook(ctx)
+		}
+		return ctx
+	default:
+		return context.WithValue(ctx, correlationsKey, m)
+	}
+}
+
+// ContextWithNoCorrelationData returns a context stripped of correlation
+// data.
+func ContextWithNoCorrelationData(ctx context.Context) context.Context {
+	return context.WithValue(ctx, correlationsKey, nil)
+}
+
+// NewContext returns a context with the map from passed context
+// updated with the passed key-value pairs.
+func NewContext(ctx context.Context, keyvalues ...attribute.KeyValue) context.Context {
+	return ContextWithMap(ctx, MapFromContext(ctx).Apply(MapUpdate{
+		MultiKV: keyvalues,
+	}))
+}
+
+// MapFromContext gets the current Map from a Context.
+func MapFromContext(ctx context.Context) Map {
+	switch v := ctx.Value(correlationsKey).(type) {
+	case correlationsData:
+		if v.getHook != nil {
+			return v.getHook(ctx, v.m)
+		}
+		return v.m
+	case Map:
+		return v
+	default:
+		return NewEmptyMap()
+	}
+}

vendor/go.opentelemetry.io/otel/internal/global/meter.go

@@ -0,0 +1,348 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package global
+
+import (
+	"context"
+	"sync"
+	"sync/atomic"
+	"unsafe"
+
+	"go.opentelemetry.io/otel/attribute"
+	"go.opentelemetry.io/otel/metric"
+	"go.opentelemetry.io/otel/metric/number"
+	"go.opentelemetry.io/otel/metric/registry"
+)
+
+// This file contains the forwarding implementation of MeterProvider used as
+// the default global instance.  Metric events using instruments provided by
+// this implementation are no-ops until the first Meter implementation is set
+// as the global provider.
+//
+// The implementation here uses Mutexes to maintain a list of active Meters in
+// the MeterProvider and Instruments in each Meter, under the assumption that
+// these interfaces are not performance-critical.
+//
+// We have the invariant that setDelegate() will be called before a new
+// MeterProvider implementation is registered as the global provider.  Mutexes
+// in the MeterProvider and Meters ensure that each instrument has a delegate
+// before the global provider is set.
+//
+// Bound instrument operations are implemented by delegating to the
+// instrument after it is registered, with a sync.Once initializer to
+// protect against races with Release().
+//
+// Metric uniqueness checking is implemented by calling the exported
+// methods of the api/metric/registry package.
+
+type meterKey struct {
+	Name, Version string
+}
+
+type meterProvider struct {
+	delegate metric.MeterProvider
+
+	// lock protects `delegate` and `meters`.
+	lock sync.Mutex
+
+	// meters maintains a unique entry for every named Meter
+	// that has been registered through the global instance.
+	meters map[meterKey]*meterEntry
+}
+
+type meterImpl struct {
+	delegate unsafe.Pointer // (*metric.MeterImpl)
+
+	lock       sync.Mutex
+	syncInsts  []*syncImpl
+	asyncInsts []*asyncImpl
+}
+
+type meterEntry struct {
+	unique metric.MeterImpl
+	impl   meterImpl
+}
+
+type instrument struct {
+	descriptor metric.Descriptor
+}
+
+type syncImpl struct {
+	delegate unsafe.Pointer // (*metric.SyncImpl)
+
+	instrument
+}
+
+type asyncImpl struct {
+	delegate unsafe.Pointer // (*metric.AsyncImpl)
+
+	instrument
+
+	runner metric.AsyncRunner
+}
+
+// SyncImpler is implemented by all of the sync metric
+// instruments.
+type SyncImpler interface {
+	SyncImpl() metric.SyncImpl
+}
+
+// AsyncImpler is implemented by all of the async
+// metric instruments.
+type AsyncImpler interface {
+	AsyncImpl() metric.AsyncImpl
+}
+
+type syncHandle struct {
+	delegate unsafe.Pointer // (*metric.BoundInstrumentImpl)
+
+	inst   *syncImpl
+	labels []attribute.KeyValue
+
+	initialize sync.Once
+}
+
+var _ metric.MeterProvider = &meterProvider{}
+var _ metric.MeterImpl = &meterImpl{}
+var _ metric.InstrumentImpl = &syncImpl{}
+var _ metric.BoundSyncImpl = &syncHandle{}
+var _ metric.AsyncImpl = &asyncImpl{}
+
+func (inst *instrument) Descriptor() metric.Descriptor {
+	return inst.descriptor
+}
+
+// MeterProvider interface and delegation
+
+func newMeterProvider() *meterProvider {
+	return &meterProvider{
+		meters: map[meterKey]*meterEntry{},
+	}
+}
+
+func (p *meterProvider) setDelegate(provider metric.MeterProvider) {
+	p.lock.Lock()
+	defer p.lock.Unlock()
+
+	p.delegate = provider
+	for key, entry := range p.meters {
+		entry.impl.setDelegate(key.Name, key.Version, provider)
+	}
+	p.meters = nil
+}
+
+func (p *meterProvider) Meter(instrumentationName string, opts ...metric.MeterOption) metric.Meter {
+	p.lock.Lock()
+	defer p.lock.Unlock()
+
+	if p.delegate != nil {
+		return p.delegate.Meter(instrumentationName, opts...)
+	}
+
+	key := meterKey{
+		Name:    instrumentationName,
+		Version: metric.NewMeterConfig(opts...).InstrumentationVersion,
+	}
+	entry, ok := p.meters[key]
+	if !ok {
+		entry = &meterEntry{}
+		entry.unique = registry.NewUniqueInstrumentMeterImpl(&entry.impl)
+		p.meters[key] = entry
+
+	}
+	return metric.WrapMeterImpl(entry.unique, key.Name, metric.WithInstrumentationVersion(key.Version))
+}
+
+// Meter interface and delegation
+
+func (m *meterImpl) setDelegate(name, version string, provider metric.MeterProvider) {
+	m.lock.Lock()
+	defer m.lock.Unlock()
+
+	d := new(metric.MeterImpl)
+	*d = provider.Meter(name, metric.WithInstrumentationVersion(version)).MeterImpl()
+	m.delegate = unsafe.Pointer(d)
+
+	for _, inst := range m.syncInsts {
+		inst.setDelegate(*d)
+	}
+	m.syncInsts = nil
+	for _, obs := range m.asyncInsts {
+		obs.setDelegate(*d)
+	}
+	m.asyncInsts = nil
+}
+
+func (m *meterImpl) NewSyncInstrument(desc metric.Descriptor) (metric.SyncImpl, error) {
+	m.lock.Lock()
+	defer m.lock.Unlock()
+
+	if meterPtr := (*metric.MeterImpl)(atomic.LoadPointer(&m.delegate)); meterPtr != nil {
+		return (*meterPtr).NewSyncInstrument(desc)
+	}
+
+	inst := &syncImpl{
+		instrument: instrument{
+			descriptor: desc,
+		},
+	}
+	m.syncInsts = append(m.syncInsts, inst)
+	return inst, nil
+}
+
+// Synchronous delegation
+
+func (inst *syncImpl) setDelegate(d metric.MeterImpl) {
+	implPtr := new(metric.SyncImpl)
+
+	var err error
+	*implPtr, err = d.NewSyncInstrument(inst.descriptor)
+
+	if err != nil {
+		// TODO: There is no standard way to deliver this error to the user.
+		// See https://github.com/open-telemetry/opentelemetry-go/issues/514
+		// Note that the default SDK will not generate any errors yet, this is
+		// only for added safety.
+		panic(err)
+	}
+
+	atomic.StorePointer(&inst.delegate, unsafe.Pointer(implPtr))
+}
+
+func (inst *syncImpl) Implementation() interface{} {
+	if implPtr := (*metric.SyncImpl)(atomic.LoadPointer(&inst.delegate)); implPtr != nil {
+		return (*implPtr).Implementation()
+	}
+	return inst
+}
+
+func (inst *syncImpl) Bind(labels []attribute.KeyValue) metric.BoundSyncImpl {
+	if implPtr := (*metric.SyncImpl)(atomic.LoadPointer(&inst.delegate)); implPtr != nil {
+		return (*implPtr).Bind(labels)
+	}
+	return &syncHandle{
+		inst:   inst,
+		labels: labels,
+	}
+}
+
+func (bound *syncHandle) Unbind() {
+	bound.initialize.Do(func() {})
+
+	implPtr := (*metric.BoundSyncImpl)(atomic.LoadPointer(&bound.delegate))
+
+	if implPtr == nil {
+		return
+	}
+
+	(*implPtr).Unbind()
+}
+
+// Async delegation
+
+func (m *meterImpl) NewAsyncInstrument(
+	desc metric.Descriptor,
+	runner metric.AsyncRunner,
+) (metric.AsyncImpl, error) {
+
+	m.lock.Lock()
+	defer m.lock.Unlock()
+
+	if meterPtr := (*metric.MeterImpl)(atomic.LoadPointer(&m.delegate)); meterPtr != nil {
+		return (*meterPtr).NewAsyncInstrument(desc, runner)
+	}
+
+	inst := &asyncImpl{
+		instrument: instrument{
+			descriptor: desc,
+		},
+		runner: runner,
+	}
+	m.asyncInsts = append(m.asyncInsts, inst)
+	return inst, nil
+}
+
+func (obs *asyncImpl) Implementation() interface{} {
+	if implPtr := (*metric.AsyncImpl)(atomic.LoadPointer(&obs.delegate)); implPtr != nil {
+		return (*implPtr).Implementation()
+	}
+	return obs
+}
+
+func (obs *asyncImpl) setDelegate(d metric.MeterImpl) {
+	implPtr := new(metric.AsyncImpl)
+
+	var err error
+	*implPtr, err = d.NewAsyncInstrument(obs.descriptor, obs.runner)
+
+	if err != nil {
+		// TODO: There is no standard way to deliver this error to the user.
+		// See https://github.com/open-telemetry/opentelemetry-go/issues/514
+		// Note that the default SDK will not generate any errors yet, this is
+		// only for added safety.
+		panic(err)
+	}
+
+	atomic.StorePointer(&obs.delegate, unsafe.Pointer(implPtr))
+}
+
+// Metric updates
+
+func (m *meterImpl) RecordBatch(ctx context.Context, labels []attribute.KeyValue, measurements ...metric.Measurement) {
+	if delegatePtr := (*metric.MeterImpl)(atomic.LoadPointer(&m.delegate)); delegatePtr != nil {
+		(*delegatePtr).RecordBatch(ctx, labels, measurements...)
+	}
+}
+
+func (inst *syncImpl) RecordOne(ctx context.Context, number number.Number, labels []attribute.KeyValue) {
+	if instPtr := (*metric.SyncImpl)(atomic.LoadPointer(&inst.delegate)); instPtr != nil {
+		(*instPtr).RecordOne(ctx, number, labels)
+	}
+}
+
+// Bound instrument initialization
+
+func (bound *syncHandle) RecordOne(ctx context.Context, number number.Number) {
+	instPtr := (*metric.SyncImpl)(atomic.LoadPointer(&bound.inst.delegate))
+	if instPtr == nil {
+		return
+	}
+	var implPtr *metric.BoundSyncImpl
+	bound.initialize.Do(func() {
+		implPtr = new(metric.BoundSyncImpl)
+		*implPtr = (*instPtr).Bind(bound.labels)
+		atomic.StorePointer(&bound.delegate, unsafe.Pointer(implPtr))
+	})
+	if implPtr == nil {
+		implPtr = (*metric.BoundSyncImpl)(atomic.LoadPointer(&bound.delegate))
+	}
+	// This may still be nil if instrument was created and bound
+	// without a delegate, then the instrument was set to have a
+	// delegate and unbound.
+	if implPtr == nil {
+		return
+	}
+	(*implPtr).RecordOne(ctx, number)
+}
+
+func AtomicFieldOffsets() map[string]uintptr {
+	return map[string]uintptr{
+		"meterProvider.delegate": unsafe.Offsetof(meterProvider{}.delegate),
+		"meterImpl.delegate":     unsafe.Offsetof(meterImpl{}.delegate),
+		"syncImpl.delegate":      unsafe.Offsetof(syncImpl{}.delegate),
+		"asyncImpl.delegate":     unsafe.Offsetof(asyncImpl{}.delegate),
+		"syncHandle.delegate":    unsafe.Offsetof(syncHandle{}.delegate),
+	}
+}

vendor/go.opentelemetry.io/otel/internal/global/propagator.go

@@ -0,0 +1,82 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package global
+
+import (
+	"context"
+	"sync"
+
+	"go.opentelemetry.io/otel/propagation"
+)
+
+// textMapPropagator is a default TextMapPropagator that delegates calls to a
+// registered delegate if one is set, otherwise it defaults to delegating the
+// calls to a the default no-op propagation.TextMapPropagator.
+type textMapPropagator struct {
+	mtx      sync.Mutex
+	once     sync.Once
+	delegate propagation.TextMapPropagator
+	noop     propagation.TextMapPropagator
+}
+
+// Compile-time guarantee that textMapPropagator implements the
+// propagation.TextMapPropagator interface.
+var _ propagation.TextMapPropagator = (*textMapPropagator)(nil)
+
+func newTextMapPropagator() *textMapPropagator {
+	return &textMapPropagator{
+		noop: propagation.NewCompositeTextMapPropagator(),
+	}
+}
+
+// SetDelegate sets a delegate propagation.TextMapPropagator that all calls are
+// forwarded to. Delegation can only be performed once, all subsequent calls
+// perform no delegation.
+func (p *textMapPropagator) SetDelegate(delegate propagation.TextMapPropagator) {
+	if delegate == nil {
+		return
+	}
+
+	p.mtx.Lock()
+	p.once.Do(func() { p.delegate = delegate })
+	p.mtx.Unlock()
+}
+
+// effectiveDelegate returns the current delegate of p if one is set,
+// otherwise the default noop TextMapPropagator is returned. This method
+// can be called concurrently.
+func (p *textMapPropagator) effectiveDelegate() propagation.TextMapPropagator {
+	p.mtx.Lock()
+	defer p.mtx.Unlock()
+	if p.delegate != nil {
+		return p.delegate
+	}
+	return p.noop
+}
+
+// Inject set cross-cutting concerns from the Context into the carrier.
+func (p *textMapPropagator) Inject(ctx context.Context, carrier propagation.TextMapCarrier) {
+	p.effectiveDelegate().Inject(ctx, carrier)
+}
+
+// Extract reads cross-cutting concerns from the carrier into a Context.
+func (p *textMapPropagator) Extract(ctx context.Context, carrier propagation.TextMapCarrier) context.Context {
+	return p.effectiveDelegate().Extract(ctx, carrier)
+}
+
+// Fields returns the keys whose values are set with Inject.
+func (p *textMapPropagator) Fields() []string {
+	return p.effectiveDelegate().Fields()
+}

vendor/go.opentelemetry.io/otel/internal/global/state.go

@@ -0,0 +1,143 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package global
+
+import (
+	"sync"
+	"sync/atomic"
+
+	"go.opentelemetry.io/otel/metric"
+	"go.opentelemetry.io/otel/propagation"
+	"go.opentelemetry.io/otel/trace"
+)
+
+type (
+	tracerProviderHolder struct {
+		tp trace.TracerProvider
+	}
+
+	meterProviderHolder struct {
+		mp metric.MeterProvider
+	}
+
+	propagatorsHolder struct {
+		tm propagation.TextMapPropagator
+	}
+)
+
+var (
+	globalTracer      = defaultTracerValue()
+	globalMeter       = defaultMeterValue()
+	globalPropagators = defaultPropagatorsValue()
+
+	delegateMeterOnce             sync.Once
+	delegateTraceOnce             sync.Once
+	delegateTextMapPropagatorOnce sync.Once
+)
+
+// TracerProvider is the internal implementation for global.TracerProvider.
+func TracerProvider() trace.TracerProvider {
+	return globalTracer.Load().(tracerProviderHolder).tp
+}
+
+// SetTracerProvider is the internal implementation for global.SetTracerProvider.
+func SetTracerProvider(tp trace.TracerProvider) {
+	delegateTraceOnce.Do(func() {
+		current := TracerProvider()
+		if current == tp {
+			// Setting the provider to the prior default is nonsense, panic.
+			// Panic is acceptable because we are likely still early in the
+			// process lifetime.
+			panic("invalid TracerProvider, the global instance cannot be reinstalled")
+		} else if def, ok := current.(*tracerProvider); ok {
+			def.setDelegate(tp)
+		}
+
+	})
+	globalTracer.Store(tracerProviderHolder{tp: tp})
+}
+
+// MeterProvider is the internal implementation for global.MeterProvider.
+func MeterProvider() metric.MeterProvider {
+	return globalMeter.Load().(meterProviderHolder).mp
+}
+
+// SetMeterProvider is the internal implementation for global.SetMeterProvider.
+func SetMeterProvider(mp metric.MeterProvider) {
+	delegateMeterOnce.Do(func() {
+		current := MeterProvider()
+
+		if current == mp {
+			// Setting the provider to the prior default is nonsense, panic.
+			// Panic is acceptable because we are likely still early in the
+			// process lifetime.
+			panic("invalid MeterProvider, the global instance cannot be reinstalled")
+		} else if def, ok := current.(*meterProvider); ok {
+			def.setDelegate(mp)
+		}
+	})
+	globalMeter.Store(meterProviderHolder{mp: mp})
+}
+
+// TextMapPropagator is the internal implementation for global.TextMapPropagator.
+func TextMapPropagator() propagation.TextMapPropagator {
+	return globalPropagators.Load().(propagatorsHolder).tm
+}
+
+// SetTextMapPropagator is the internal implementation for global.SetTextMapPropagator.
+func SetTextMapPropagator(p propagation.TextMapPropagator) {
+	// For the textMapPropagator already returned by TextMapPropagator
+	// delegate to p.
+	delegateTextMapPropagatorOnce.Do(func() {
+		if current := TextMapPropagator(); current == p {
+			// Setting the provider to the prior default is nonsense, panic.
+			// Panic is acceptable because we are likely still early in the
+			// process lifetime.
+			panic("invalid TextMapPropagator, the global instance cannot be reinstalled")
+		} else if def, ok := current.(*textMapPropagator); ok {
+			def.SetDelegate(p)
+		}
+	})
+	// Return p when subsequent calls to TextMapPropagator are made.
+	globalPropagators.Store(propagatorsHolder{tm: p})
+}
+
+func defaultTracerValue() *atomic.Value {
+	v := &atomic.Value{}
+	v.Store(tracerProviderHolder{tp: &tracerProvider{}})
+	return v
+}
+
+func defaultMeterValue() *atomic.Value {
+	v := &atomic.Value{}
+	v.Store(meterProviderHolder{mp: newMeterProvider()})
+	return v
+}
+
+func defaultPropagatorsValue() *atomic.Value {
+	v := &atomic.Value{}
+	v.Store(propagatorsHolder{tm: newTextMapPropagator()})
+	return v
+}
+
+// ResetForTest restores the initial global state, for testing purposes.
+func ResetForTest() {
+	globalTracer = defaultTracerValue()
+	globalMeter = defaultMeterValue()
+	globalPropagators = defaultPropagatorsValue()
+	delegateMeterOnce = sync.Once{}
+	delegateTraceOnce = sync.Once{}
+	delegateTextMapPropagatorOnce = sync.Once{}
+}

vendor/go.opentelemetry.io/otel/internal/global/trace.go

@@ -0,0 +1,147 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package global
+
+/*
+This file contains the forwarding implementation of the TracerProvider used as
+the default global instance. Prior to initialization of an SDK, Tracers
+returned by the global TracerProvider will provide no-op functionality. This
+means that all Span created prior to initialization are no-op Spans.
+
+Once an SDK has been initialized, all provided no-op Tracers are swapped for
+Tracers provided by the SDK defined TracerProvider. However, any Span started
+prior to this initialization does not change its behavior. Meaning, the Span
+remains a no-op Span.
+
+The implementation to track and swap Tracers locks all new Tracer creation
+until the swap is complete. This assumes that this operation is not
+performance-critical. If that assumption is incorrect, be sure to configure an
+SDK prior to any Tracer creation.
+*/
+
+import (
+	"context"
+	"sync"
+	"sync/atomic"
+
+	"go.opentelemetry.io/otel/internal/trace/noop"
+	"go.opentelemetry.io/otel/trace"
+)
+
+// tracerProvider is a placeholder for a configured SDK TracerProvider.
+//
+// All TracerProvider functionality is forwarded to a delegate once
+// configured.
+type tracerProvider struct {
+	mtx      sync.Mutex
+	tracers  map[il]*tracer
+	delegate trace.TracerProvider
+}
+
+// Compile-time guarantee that tracerProvider implements the TracerProvider
+// interface.
+var _ trace.TracerProvider = &tracerProvider{}
+
+// setDelegate configures p to delegate all TracerProvider functionality to
+// provider.
+//
+// All Tracers provided prior to this function call are switched out to be
+// Tracers provided by provider.
+//
+// It is guaranteed by the caller that this happens only once.
+func (p *tracerProvider) setDelegate(provider trace.TracerProvider) {
+	p.mtx.Lock()
+	defer p.mtx.Unlock()
+
+	p.delegate = provider
+
+	if len(p.tracers) == 0 {
+		return
+	}
+
+	for _, t := range p.tracers {
+		t.setDelegate(provider)
+	}
+
+	p.tracers = nil
+}
+
+// Tracer implements TracerProvider.
+func (p *tracerProvider) Tracer(name string, opts ...trace.TracerOption) trace.Tracer {
+	p.mtx.Lock()
+	defer p.mtx.Unlock()
+
+	if p.delegate != nil {
+		return p.delegate.Tracer(name, opts...)
+	}
+
+	// At this moment it is guaranteed that no sdk is installed, save the tracer in the tracers map.
+
+	key := il{
+		name:    name,
+		version: trace.NewTracerConfig(opts...).InstrumentationVersion,
+	}
+
+	if p.tracers == nil {
+		p.tracers = make(map[il]*tracer)
+	}
+
+	if val, ok := p.tracers[key]; ok {
+		return val
+	}
+
+	t := &tracer{name: name, opts: opts}
+	p.tracers[key] = t
+	return t
+}
+
+type il struct {
+	name    string
+	version string
+}
+
+// tracer is a placeholder for a trace.Tracer.
+//
+// All Tracer functionality is forwarded to a delegate once configured.
+// Otherwise, all functionality is forwarded to a NoopTracer.
+type tracer struct {
+	name string
+	opts []trace.TracerOption
+
+	delegate atomic.Value
+}
+
+// Compile-time guarantee that tracer implements the trace.Tracer interface.
+var _ trace.Tracer = &tracer{}
+
+// setDelegate configures t to delegate all Tracer functionality to Tracers
+// created by provider.
+//
+// All subsequent calls to the Tracer methods will be passed to the delegate.
+//
+// It is guaranteed by the caller that this happens only once.
+func (t *tracer) setDelegate(provider trace.TracerProvider) {
+	t.delegate.Store(provider.Tracer(t.name, t.opts...))
+}
+
+// Start implements trace.Tracer by forwarding the call to t.delegate if
+// set, otherwise it forwards the call to a NoopTracer.
+func (t *tracer) Start(ctx context.Context, name string, opts ...trace.SpanOption) (context.Context, trace.Span) {
+	delegate := t.delegate.Load()
+	if delegate != nil {
+		return delegate.(trace.Tracer).Start(ctx, name, opts...)
+	}
+	return noop.Tracer.Start(ctx, name, opts...)
+}

vendor/go.opentelemetry.io/otel/internal/metric/async.go

@@ -0,0 +1,148 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package metric
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"sync"
+
+	"go.opentelemetry.io/otel"
+	"go.opentelemetry.io/otel/attribute"
+	"go.opentelemetry.io/otel/metric"
+)
+
+var ErrInvalidAsyncRunner = errors.New("unknown async runner type")
+
+// AsyncCollector is an interface used between the MeterImpl and the
+// AsyncInstrumentState helper below.  This interface is implemented by
+// the SDK to provide support for running observer callbacks.
+type AsyncCollector interface {
+	// CollectAsync passes a batch of observations to the MeterImpl.
+	CollectAsync(labels []attribute.KeyValue, observation ...metric.Observation)
+}
+
+// AsyncInstrumentState manages an ordered set of asynchronous
+// instruments and the distinct runners, taking into account batch
+// observer callbacks.
+type AsyncInstrumentState struct {
+	lock sync.Mutex
+
+	// errorOnce will use the otel.Handler to report an error
+	// once in case of an invalid runner attempting to run.
+	errorOnce sync.Once
+
+	// runnerMap keeps the set of runners that will run each
+	// collection interval.  Singletons are entered with a real
+	// instrument each, batch observers are entered with a nil
+	// instrument, ensuring that when a singleton callback is used
+	// repeatedly, it is executed repeatedly in the interval, while
+	// when a batch callback is used repeatedly, it only executes
+	// once per interval.
+	runnerMap map[asyncRunnerPair]struct{}
+
+	// runners maintains the set of runners in the order they were
+	// registered.
+	runners []asyncRunnerPair
+
+	// instruments maintains the set of instruments in the order
+	// they were registered.
+	instruments []metric.AsyncImpl
+}
+
+// asyncRunnerPair is a map entry for Observer callback runners.
+type asyncRunnerPair struct {
+	// runner is used as a map key here.  The API ensures
+	// that all callbacks are pointers for this reason.
+	runner metric.AsyncRunner
+
+	// inst refers to a non-nil instrument when `runner` is a
+	// AsyncSingleRunner.
+	inst metric.AsyncImpl
+}
+
+// NewAsyncInstrumentState returns a new *AsyncInstrumentState, for
+// use by MeterImpl to manage running the set of observer callbacks in
+// the correct order.
+func NewAsyncInstrumentState() *AsyncInstrumentState {
+	return &AsyncInstrumentState{
+		runnerMap: map[asyncRunnerPair]struct{}{},
+	}
+}
+
+// Instruments returns the asynchronous instruments managed by this
+// object, the set that should be checkpointed after observers are
+// run.
+func (a *AsyncInstrumentState) Instruments() []metric.AsyncImpl {
+	a.lock.Lock()
+	defer a.lock.Unlock()
+	return a.instruments
+}
+
+// Register adds a new asynchronous instrument to by managed by this
+// object.  This should be called during NewAsyncInstrument() and
+// assumes that errors (e.g., duplicate registration) have already
+// been checked.
+func (a *AsyncInstrumentState) Register(inst metric.AsyncImpl, runner metric.AsyncRunner) {
+	a.lock.Lock()
+	defer a.lock.Unlock()
+
+	a.instruments = append(a.instruments, inst)
+
+	// asyncRunnerPair reflects this callback in the asyncRunners
+	// list.  If this is a batch runner, the instrument is nil.
+	// If this is a single-Observer runner, the instrument is
+	// included.  This ensures that batch callbacks are called
+	// once and single callbacks are called once per instrument.
+	rp := asyncRunnerPair{
+		runner: runner,
+	}
+	if _, ok := runner.(metric.AsyncSingleRunner); ok {
+		rp.inst = inst
+	}
+
+	if _, ok := a.runnerMap[rp]; !ok {
+		a.runnerMap[rp] = struct{}{}
+		a.runners = append(a.runners, rp)
+	}
+}
+
+// Run executes the complete set of observer callbacks.
+func (a *AsyncInstrumentState) Run(ctx context.Context, collector AsyncCollector) {
+	a.lock.Lock()
+	runners := a.runners
+	a.lock.Unlock()
+
+	for _, rp := range runners {
+		// The runner must be a single or batch runner, no
+		// other implementations are possible because the
+		// interface has un-exported methods.
+
+		if singleRunner, ok := rp.runner.(metric.AsyncSingleRunner); ok {
+			singleRunner.Run(ctx, rp.inst, collector.CollectAsync)
+			continue
+		}
+
+		if multiRunner, ok := rp.runner.(metric.AsyncBatchRunner); ok {
+			multiRunner.Run(ctx, collector.CollectAsync)
+			continue
+		}
+
+		a.errorOnce.Do(func() {
+			otel.Handle(fmt.Errorf("%w: type %T (reported once)", ErrInvalidAsyncRunner, rp))
+		})
+	}
+}

vendor/go.opentelemetry.io/otel/internal/rawhelpers.go

@@ -0,0 +1,55 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package internal
+
+import (
+	"math"
+	"unsafe"
+)
+
+func BoolToRaw(b bool) uint64 {
+	if b {
+		return 1
+	}
+	return 0
+}
+
+func RawToBool(r uint64) bool {
+	return r != 0
+}
+
+func Int64ToRaw(i int64) uint64 {
+	return uint64(i)
+}
+
+func RawToInt64(r uint64) int64 {
+	return int64(r)
+}
+
+func Float64ToRaw(f float64) uint64 {
+	return math.Float64bits(f)
+}
+
+func RawToFloat64(r uint64) float64 {
+	return math.Float64frombits(r)
+}
+
+func RawPtrToFloat64Ptr(r *uint64) *float64 {
+	return (*float64)(unsafe.Pointer(r))
+}
+
+func RawPtrToInt64Ptr(r *uint64) *int64 {
+	return (*int64)(unsafe.Pointer(r))
+}

vendor/go.opentelemetry.io/otel/internal/trace/noop/noop.go

@@ -0,0 +1,35 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package noop provides noop tracing implementations for tracer and span.
+package noop
+
+import (
+	"context"
+
+	"go.opentelemetry.io/otel/trace"
+)
+
+var (
+	// Tracer is a noop tracer that starts noop spans.
+	Tracer trace.Tracer
+
+	// Span is a noop Span.
+	Span trace.Span
+)
+
+func init() {
+	Tracer = trace.NewNoopTracerProvider().Tracer("")
+	_, Span = Tracer.Start(context.Background(), "")
+}

vendor/go.opentelemetry.io/otel/metric/LICENSE

@@ -0,0 +1,201 @@
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.

vendor/go.opentelemetry.io/otel/metric/config.go

@@ -0,0 +1,128 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package metric // import "go.opentelemetry.io/otel/metric"
+
+import (
+	"go.opentelemetry.io/otel/unit"
+)
+
+// InstrumentConfig contains options for metric instrument descriptors.
+type InstrumentConfig struct {
+	// Description describes the instrument in human-readable terms.
+	Description string
+	// Unit describes the measurement unit for a instrument.
+	Unit unit.Unit
+	// InstrumentationName is the name of the library providing
+	// instrumentation.
+	InstrumentationName string
+	// InstrumentationVersion is the version of the library providing
+	// instrumentation.
+	InstrumentationVersion string
+}
+
+// InstrumentOption is an interface for applying metric instrument options.
+type InstrumentOption interface {
+	// ApplyMeter is used to set a InstrumentOption value of a
+	// InstrumentConfig.
+	ApplyInstrument(*InstrumentConfig)
+}
+
+// NewInstrumentConfig creates a new InstrumentConfig
+// and applies all the given options.
+func NewInstrumentConfig(opts ...InstrumentOption) InstrumentConfig {
+	var config InstrumentConfig
+	for _, o := range opts {
+		o.ApplyInstrument(&config)
+	}
+	return config
+}
+
+// WithDescription applies provided description.
+func WithDescription(desc string) InstrumentOption {
+	return descriptionOption(desc)
+}
+
+type descriptionOption string
+
+func (d descriptionOption) ApplyInstrument(config *InstrumentConfig) {
+	config.Description = string(d)
+}
+
+// WithUnit applies provided unit.
+func WithUnit(unit unit.Unit) InstrumentOption {
+	return unitOption(unit)
+}
+
+type unitOption unit.Unit
+
+func (u unitOption) ApplyInstrument(config *InstrumentConfig) {
+	config.Unit = unit.Unit(u)
+}
+
+// WithInstrumentationName sets the instrumentation name.
+func WithInstrumentationName(name string) InstrumentOption {
+	return instrumentationNameOption(name)
+}
+
+type instrumentationNameOption string
+
+func (i instrumentationNameOption) ApplyInstrument(config *InstrumentConfig) {
+	config.InstrumentationName = string(i)
+}
+
+// MeterConfig contains options for Meters.
+type MeterConfig struct {
+	// InstrumentationVersion is the version of the library providing
+	// instrumentation.
+	InstrumentationVersion string
+}
+
+// MeterOption is an interface for applying Meter options.
+type MeterOption interface {
+	// ApplyMeter is used to set a MeterOption value of a MeterConfig.
+	ApplyMeter(*MeterConfig)
+}
+
+// NewMeterConfig creates a new MeterConfig and applies
+// all the given options.
+func NewMeterConfig(opts ...MeterOption) MeterConfig {
+	var config MeterConfig
+	for _, o := range opts {
+		o.ApplyMeter(&config)
+	}
+	return config
+}
+
+// InstrumentationOption is an interface for applying instrumentation specific
+// options.
+type InstrumentationOption interface {
+	InstrumentOption
+	MeterOption
+}
+
+// WithInstrumentationVersion sets the instrumentation version.
+func WithInstrumentationVersion(version string) InstrumentationOption {
+	return instrumentationVersionOption(version)
+}
+
+type instrumentationVersionOption string
+
+func (i instrumentationVersionOption) ApplyMeter(config *MeterConfig) {
+	config.InstrumentationVersion = string(i)
+}
+
+func (i instrumentationVersionOption) ApplyInstrument(config *InstrumentConfig) {
+	config.InstrumentationVersion = string(i)
+}

vendor/go.opentelemetry.io/otel/metric/doc.go

@@ -0,0 +1,67 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+/*
+Package metric provides an implementation of the metrics part of the
+OpenTelemetry API.
+
+This package is currently in a pre-GA phase. Backwards incompatible changes
+may be introduced in subsequent minor version releases as we work to track the
+evolving OpenTelemetry specification and user feedback.
+
+Measurements can be made about an operation being performed or the state of a
+system in general. These measurements can be crucial to the reliable operation
+of code and provide valuable insights about the inner workings of a system.
+
+Measurements are made using instruments provided by this package. The type of
+instrument used will depend on the type of measurement being made and of what
+part of a system is being measured.
+
+Instruments are categorized as Synchronous or Asynchronous and independently
+as Adding or Grouping. Synchronous instruments are called by the user with a
+Context. Asynchronous instruments are called by the SDK during collection.
+Additive instruments are semantically intended for capturing a sum. Grouping
+instruments are intended for capturing a distribution.
+
+Additive instruments may be monotonic, in which case they are non-decreasing
+and naturally define a rate.
+
+The synchronous instrument names are:
+
+  Counter:           additive, monotonic
+  UpDownCounter:     additive
+  ValueRecorder:     grouping
+
+and the asynchronous instruments are:
+
+  SumObserver:       additive, monotonic
+  UpDownSumObserver: additive
+  ValueObserver:     grouping
+
+All instruments are provided with support for either float64 or int64 input
+values.
+
+An instrument is created using a Meter. Additionally, a Meter is used to
+record batches of synchronous measurements or asynchronous observations. A
+Meter is obtained using a MeterProvider. A Meter, like a Tracer, is unique to
+the instrumentation it instruments and must be named and versioned when
+created with a MeterProvider with the name and version of the instrumentation
+library.
+
+Instrumentation should be designed to accept a MeterProvider from which it can
+create its own unique Meter. Alternatively, the registered global
+MeterProvider from the go.opentelemetry.io/otel package can be used as a
+default.
+*/
+package metric // import "go.opentelemetry.io/otel/metric"

vendor/go.opentelemetry.io/otel/metric/global/metric.go

@@ -0,0 +1,49 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package global // import "go.opentelemetry.io/otel/metric/global"
+
+import (
+	"go.opentelemetry.io/otel/internal/global"
+	"go.opentelemetry.io/otel/metric"
+)
+
+// Meter creates an implementation of the Meter interface from the global
+// MeterProvider. The instrumentationName must be the name of the library
+// providing instrumentation. This name may be the same as the instrumented
+// code only if that code provides built-in instrumentation. If the
+// instrumentationName is empty, then a implementation defined default name
+// will be used instead.
+//
+// This is short for MeterProvider().Meter(name)
+func Meter(instrumentationName string, opts ...metric.MeterOption) metric.Meter {
+	return GetMeterProvider().Meter(instrumentationName, opts...)
+}
+
+// GetMeterProvider returns the registered global meter provider.  If
+// none is registered then a default meter provider is returned that
+// forwards the Meter interface to the first registered Meter.
+//
+// Use the meter provider to create a named meter. E.g.
+//     meter := global.MeterProvider().Meter("example.com/foo")
+// or
+//     meter := global.Meter("example.com/foo")
+func GetMeterProvider() metric.MeterProvider {
+	return global.MeterProvider()
+}
+
+// SetMeterProvider registers `mp` as the global meter provider.
+func SetMeterProvider(mp metric.MeterProvider) {
+	global.SetMeterProvider(mp)
+}

vendor/go.opentelemetry.io/otel/metric/go.mod

@@ -0,0 +1,54 @@
+module go.opentelemetry.io/otel/metric
+
+go 1.14
+
+replace go.opentelemetry.io/otel => ../
+
+replace go.opentelemetry.io/otel/bridge/opencensus => ../bridge/opencensus
+
+replace go.opentelemetry.io/otel/bridge/opentracing => ../bridge/opentracing
+
+replace go.opentelemetry.io/otel/example/jaeger => ../example/jaeger
+
+replace go.opentelemetry.io/otel/example/namedtracer => ../example/namedtracer
+
+replace go.opentelemetry.io/otel/example/opencensus => ../example/opencensus
+
+replace go.opentelemetry.io/otel/example/otel-collector => ../example/otel-collector
+
+replace go.opentelemetry.io/otel/example/prom-collector => ../example/prom-collector
+
+replace go.opentelemetry.io/otel/example/prometheus => ../example/prometheus
+
+replace go.opentelemetry.io/otel/example/zipkin => ../example/zipkin
+
+replace go.opentelemetry.io/otel/exporters/metric/prometheus => ../exporters/metric/prometheus
+
+replace go.opentelemetry.io/otel/exporters/otlp => ../exporters/otlp
+
+replace go.opentelemetry.io/otel/exporters/stdout => ../exporters/stdout
+
+replace go.opentelemetry.io/otel/exporters/trace/jaeger => ../exporters/trace/jaeger
+
+replace go.opentelemetry.io/otel/exporters/trace/zipkin => ../exporters/trace/zipkin
+
+replace go.opentelemetry.io/otel/internal/tools => ../internal/tools
+
+replace go.opentelemetry.io/otel/metric => ./
+
+replace go.opentelemetry.io/otel/oteltest => ../oteltest
+
+replace go.opentelemetry.io/otel/sdk => ../sdk
+
+replace go.opentelemetry.io/otel/sdk/export/metric => ../sdk/export/metric
+
+replace go.opentelemetry.io/otel/sdk/metric => ../sdk/metric
+
+replace go.opentelemetry.io/otel/trace => ../trace
+
+require (
+	github.com/google/go-cmp v0.5.5
+	github.com/stretchr/testify v1.7.0
+	go.opentelemetry.io/otel v0.20.0
+	go.opentelemetry.io/otel/oteltest v0.20.0
+)

vendor/go.opentelemetry.io/otel/metric/go.sum

@@ -0,0 +1,15 @@
+github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8=
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/google/go-cmp v0.5.5 h1:Khx7svrCpmxxtHBq5j2mp/xVjsi8hQMfNLvJFAlrGgU=
+github.com/google/go-cmp v0.5.5/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/testify v1.7.0 h1:nwc3DEeHmmLAfoZucVR881uASk0Mfjw8xYJ99tb5CcY=
+github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
+golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543 h1:E7g+9GITq07hpfrRu66IVDexMakfv52eLZ2CXBWiKr4=
+golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c h1:dUUwHk2QECo/6vqA44rthZ8ie2QXMNeKRTHCNY2nXvo=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

vendor/go.opentelemetry.io/otel/metric/instrumentkind_string.go

@@ -0,0 +1,28 @@
+// Code generated by "stringer -type=InstrumentKind"; DO NOT EDIT.
+
+package metric
+
+import "strconv"
+
+func _() {
+	// An "invalid array index" compiler error signifies that the constant values have changed.
+	// Re-run the stringer command to generate them again.
+	var x [1]struct{}
+	_ = x[ValueRecorderInstrumentKind-0]
+	_ = x[ValueObserverInstrumentKind-1]
+	_ = x[CounterInstrumentKind-2]
+	_ = x[UpDownCounterInstrumentKind-3]
+	_ = x[SumObserverInstrumentKind-4]
+	_ = x[UpDownSumObserverInstrumentKind-5]
+}
+
+const _InstrumentKind_name = "ValueRecorderInstrumentKindValueObserverInstrumentKindCounterInstrumentKindUpDownCounterInstrumentKindSumObserverInstrumentKindUpDownSumObserverInstrumentKind"
+
+var _InstrumentKind_index = [...]uint8{0, 27, 54, 75, 102, 127, 158}
+
+func (i InstrumentKind) String() string {
+	if i < 0 || i >= InstrumentKind(len(_InstrumentKind_index)-1) {
+		return "InstrumentKind(" + strconv.FormatInt(int64(i), 10) + ")"
+	}
+	return _InstrumentKind_name[_InstrumentKind_index[i]:_InstrumentKind_index[i+1]]
+}

vendor/go.opentelemetry.io/otel/metric/metric.go

@@ -0,0 +1,577 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package metric // import "go.opentelemetry.io/otel/metric"
+
+import (
+	"context"
+
+	"go.opentelemetry.io/otel/attribute"
+	"go.opentelemetry.io/otel/metric/number"
+	"go.opentelemetry.io/otel/unit"
+)
+
+// MeterProvider supports named Meter instances.
+type MeterProvider interface {
+	// Meter creates an implementation of the Meter interface.
+	// The instrumentationName must be the name of the library providing
+	// instrumentation. This name may be the same as the instrumented code
+	// only if that code provides built-in instrumentation. If the
+	// instrumentationName is empty, then a implementation defined default
+	// name will be used instead.
+	Meter(instrumentationName string, opts ...MeterOption) Meter
+}
+
+// Meter is the creator of metric instruments.
+//
+// An uninitialized Meter is a no-op implementation.
+type Meter struct {
+	impl          MeterImpl
+	name, version string
+}
+
+// RecordBatch atomically records a batch of measurements.
+func (m Meter) RecordBatch(ctx context.Context, ls []attribute.KeyValue, ms ...Measurement) {
+	if m.impl == nil {
+		return
+	}
+	m.impl.RecordBatch(ctx, ls, ms...)
+}
+
+// NewBatchObserver creates a new BatchObserver that supports
+// making batches of observations for multiple instruments.
+func (m Meter) NewBatchObserver(callback BatchObserverFunc) BatchObserver {
+	return BatchObserver{
+		meter:  m,
+		runner: newBatchAsyncRunner(callback),
+	}
+}
+
+// NewInt64Counter creates a new integer Counter instrument with the
+// given name, customized with options.  May return an error if the
+// name is invalid (e.g., empty) or improperly registered (e.g.,
+// duplicate registration).
+func (m Meter) NewInt64Counter(name string, options ...InstrumentOption) (Int64Counter, error) {
+	return wrapInt64CounterInstrument(
+		m.newSync(name, CounterInstrumentKind, number.Int64Kind, options))
+}
+
+// NewFloat64Counter creates a new floating point Counter with the
+// given name, customized with options.  May return an error if the
+// name is invalid (e.g., empty) or improperly registered (e.g.,
+// duplicate registration).
+func (m Meter) NewFloat64Counter(name string, options ...InstrumentOption) (Float64Counter, error) {
+	return wrapFloat64CounterInstrument(
+		m.newSync(name, CounterInstrumentKind, number.Float64Kind, options))
+}
+
+// NewInt64UpDownCounter creates a new integer UpDownCounter instrument with the
+// given name, customized with options.  May return an error if the
+// name is invalid (e.g., empty) or improperly registered (e.g.,
+// duplicate registration).
+func (m Meter) NewInt64UpDownCounter(name string, options ...InstrumentOption) (Int64UpDownCounter, error) {
+	return wrapInt64UpDownCounterInstrument(
+		m.newSync(name, UpDownCounterInstrumentKind, number.Int64Kind, options))
+}
+
+// NewFloat64UpDownCounter creates a new floating point UpDownCounter with the
+// given name, customized with options.  May return an error if the
+// name is invalid (e.g., empty) or improperly registered (e.g.,
+// duplicate registration).
+func (m Meter) NewFloat64UpDownCounter(name string, options ...InstrumentOption) (Float64UpDownCounter, error) {
+	return wrapFloat64UpDownCounterInstrument(
+		m.newSync(name, UpDownCounterInstrumentKind, number.Float64Kind, options))
+}
+
+// NewInt64ValueRecorder creates a new integer ValueRecorder instrument with the
+// given name, customized with options.  May return an error if the
+// name is invalid (e.g., empty) or improperly registered (e.g.,
+// duplicate registration).
+func (m Meter) NewInt64ValueRecorder(name string, opts ...InstrumentOption) (Int64ValueRecorder, error) {
+	return wrapInt64ValueRecorderInstrument(
+		m.newSync(name, ValueRecorderInstrumentKind, number.Int64Kind, opts))
+}
+
+// NewFloat64ValueRecorder creates a new floating point ValueRecorder with the
+// given name, customized with options.  May return an error if the
+// name is invalid (e.g., empty) or improperly registered (e.g.,
+// duplicate registration).
+func (m Meter) NewFloat64ValueRecorder(name string, opts ...InstrumentOption) (Float64ValueRecorder, error) {
+	return wrapFloat64ValueRecorderInstrument(
+		m.newSync(name, ValueRecorderInstrumentKind, number.Float64Kind, opts))
+}
+
+// NewInt64ValueObserver creates a new integer ValueObserver instrument
+// with the given name, running a given callback, and customized with
+// options.  May return an error if the name is invalid (e.g., empty)
+// or improperly registered (e.g., duplicate registration).
+func (m Meter) NewInt64ValueObserver(name string, callback Int64ObserverFunc, opts ...InstrumentOption) (Int64ValueObserver, error) {
+	if callback == nil {
+		return wrapInt64ValueObserverInstrument(NoopAsync{}, nil)
+	}
+	return wrapInt64ValueObserverInstrument(
+		m.newAsync(name, ValueObserverInstrumentKind, number.Int64Kind, opts,
+			newInt64AsyncRunner(callback)))
+}
+
+// NewFloat64ValueObserver creates a new floating point ValueObserver with
+// the given name, running a given callback, and customized with
+// options.  May return an error if the name is invalid (e.g., empty)
+// or improperly registered (e.g., duplicate registration).
+func (m Meter) NewFloat64ValueObserver(name string, callback Float64ObserverFunc, opts ...InstrumentOption) (Float64ValueObserver, error) {
+	if callback == nil {
+		return wrapFloat64ValueObserverInstrument(NoopAsync{}, nil)
+	}
+	return wrapFloat64ValueObserverInstrument(
+		m.newAsync(name, ValueObserverInstrumentKind, number.Float64Kind, opts,
+			newFloat64AsyncRunner(callback)))
+}
+
+// NewInt64SumObserver creates a new integer SumObserver instrument
+// with the given name, running a given callback, and customized with
+// options.  May return an error if the name is invalid (e.g., empty)
+// or improperly registered (e.g., duplicate registration).
+func (m Meter) NewInt64SumObserver(name string, callback Int64ObserverFunc, opts ...InstrumentOption) (Int64SumObserver, error) {
+	if callback == nil {
+		return wrapInt64SumObserverInstrument(NoopAsync{}, nil)
+	}
+	return wrapInt64SumObserverInstrument(
+		m.newAsync(name, SumObserverInstrumentKind, number.Int64Kind, opts,
+			newInt64AsyncRunner(callback)))
+}
+
+// NewFloat64SumObserver creates a new floating point SumObserver with
+// the given name, running a given callback, and customized with
+// options.  May return an error if the name is invalid (e.g., empty)
+// or improperly registered (e.g., duplicate registration).
+func (m Meter) NewFloat64SumObserver(name string, callback Float64ObserverFunc, opts ...InstrumentOption) (Float64SumObserver, error) {
+	if callback == nil {
+		return wrapFloat64SumObserverInstrument(NoopAsync{}, nil)
+	}
+	return wrapFloat64SumObserverInstrument(
+		m.newAsync(name, SumObserverInstrumentKind, number.Float64Kind, opts,
+			newFloat64AsyncRunner(callback)))
+}
+
+// NewInt64UpDownSumObserver creates a new integer UpDownSumObserver instrument
+// with the given name, running a given callback, and customized with
+// options.  May return an error if the name is invalid (e.g., empty)
+// or improperly registered (e.g., duplicate registration).
+func (m Meter) NewInt64UpDownSumObserver(name string, callback Int64ObserverFunc, opts ...InstrumentOption) (Int64UpDownSumObserver, error) {
+	if callback == nil {
+		return wrapInt64UpDownSumObserverInstrument(NoopAsync{}, nil)
+	}
+	return wrapInt64UpDownSumObserverInstrument(
+		m.newAsync(name, UpDownSumObserverInstrumentKind, number.Int64Kind, opts,
+			newInt64AsyncRunner(callback)))
+}
+
+// NewFloat64UpDownSumObserver creates a new floating point UpDownSumObserver with
+// the given name, running a given callback, and customized with
+// options.  May return an error if the name is invalid (e.g., empty)
+// or improperly registered (e.g., duplicate registration).
+func (m Meter) NewFloat64UpDownSumObserver(name string, callback Float64ObserverFunc, opts ...InstrumentOption) (Float64UpDownSumObserver, error) {
+	if callback == nil {
+		return wrapFloat64UpDownSumObserverInstrument(NoopAsync{}, nil)
+	}
+	return wrapFloat64UpDownSumObserverInstrument(
+		m.newAsync(name, UpDownSumObserverInstrumentKind, number.Float64Kind, opts,
+			newFloat64AsyncRunner(callback)))
+}
+
+// NewInt64ValueObserver creates a new integer ValueObserver instrument
+// with the given name, running in a batch callback, and customized with
+// options.  May return an error if the name is invalid (e.g., empty)
+// or improperly registered (e.g., duplicate registration).
+func (b BatchObserver) NewInt64ValueObserver(name string, opts ...InstrumentOption) (Int64ValueObserver, error) {
+	if b.runner == nil {
+		return wrapInt64ValueObserverInstrument(NoopAsync{}, nil)
+	}
+	return wrapInt64ValueObserverInstrument(
+		b.meter.newAsync(name, ValueObserverInstrumentKind, number.Int64Kind, opts, b.runner))
+}
+
+// NewFloat64ValueObserver creates a new floating point ValueObserver with
+// the given name, running in a batch callback, and customized with
+// options.  May return an error if the name is invalid (e.g., empty)
+// or improperly registered (e.g., duplicate registration).
+func (b BatchObserver) NewFloat64ValueObserver(name string, opts ...InstrumentOption) (Float64ValueObserver, error) {
+	if b.runner == nil {
+		return wrapFloat64ValueObserverInstrument(NoopAsync{}, nil)
+	}
+	return wrapFloat64ValueObserverInstrument(
+		b.meter.newAsync(name, ValueObserverInstrumentKind, number.Float64Kind, opts,
+			b.runner))
+}
+
+// NewInt64SumObserver creates a new integer SumObserver instrument
+// with the given name, running in a batch callback, and customized with
+// options.  May return an error if the name is invalid (e.g., empty)
+// or improperly registered (e.g., duplicate registration).
+func (b BatchObserver) NewInt64SumObserver(name string, opts ...InstrumentOption) (Int64SumObserver, error) {
+	if b.runner == nil {
+		return wrapInt64SumObserverInstrument(NoopAsync{}, nil)
+	}
+	return wrapInt64SumObserverInstrument(
+		b.meter.newAsync(name, SumObserverInstrumentKind, number.Int64Kind, opts, b.runner))
+}
+
+// NewFloat64SumObserver creates a new floating point SumObserver with
+// the given name, running in a batch callback, and customized with
+// options.  May return an error if the name is invalid (e.g., empty)
+// or improperly registered (e.g., duplicate registration).
+func (b BatchObserver) NewFloat64SumObserver(name string, opts ...InstrumentOption) (Float64SumObserver, error) {
+	if b.runner == nil {
+		return wrapFloat64SumObserverInstrument(NoopAsync{}, nil)
+	}
+	return wrapFloat64SumObserverInstrument(
+		b.meter.newAsync(name, SumObserverInstrumentKind, number.Float64Kind, opts,
+			b.runner))
+}
+
+// NewInt64UpDownSumObserver creates a new integer UpDownSumObserver instrument
+// with the given name, running in a batch callback, and customized with
+// options.  May return an error if the name is invalid (e.g., empty)
+// or improperly registered (e.g., duplicate registration).
+func (b BatchObserver) NewInt64UpDownSumObserver(name string, opts ...InstrumentOption) (Int64UpDownSumObserver, error) {
+	if b.runner == nil {
+		return wrapInt64UpDownSumObserverInstrument(NoopAsync{}, nil)
+	}
+	return wrapInt64UpDownSumObserverInstrument(
+		b.meter.newAsync(name, UpDownSumObserverInstrumentKind, number.Int64Kind, opts, b.runner))
+}
+
+// NewFloat64UpDownSumObserver creates a new floating point UpDownSumObserver with
+// the given name, running in a batch callback, and customized with
+// options.  May return an error if the name is invalid (e.g., empty)
+// or improperly registered (e.g., duplicate registration).
+func (b BatchObserver) NewFloat64UpDownSumObserver(name string, opts ...InstrumentOption) (Float64UpDownSumObserver, error) {
+	if b.runner == nil {
+		return wrapFloat64UpDownSumObserverInstrument(NoopAsync{}, nil)
+	}
+	return wrapFloat64UpDownSumObserverInstrument(
+		b.meter.newAsync(name, UpDownSumObserverInstrumentKind, number.Float64Kind, opts,
+			b.runner))
+}
+
+// MeterImpl returns the underlying MeterImpl of this Meter.
+func (m Meter) MeterImpl() MeterImpl {
+	return m.impl
+}
+
+// newAsync constructs one new asynchronous instrument.
+func (m Meter) newAsync(
+	name string,
+	mkind InstrumentKind,
+	nkind number.Kind,
+	opts []InstrumentOption,
+	runner AsyncRunner,
+) (
+	AsyncImpl,
+	error,
+) {
+	if m.impl == nil {
+		return NoopAsync{}, nil
+	}
+	desc := NewDescriptor(name, mkind, nkind, opts...)
+	desc.config.InstrumentationName = m.name
+	desc.config.InstrumentationVersion = m.version
+	return m.impl.NewAsyncInstrument(desc, runner)
+}
+
+// newSync constructs one new synchronous instrument.
+func (m Meter) newSync(
+	name string,
+	metricKind InstrumentKind,
+	numberKind number.Kind,
+	opts []InstrumentOption,
+) (
+	SyncImpl,
+	error,
+) {
+	if m.impl == nil {
+		return NoopSync{}, nil
+	}
+	desc := NewDescriptor(name, metricKind, numberKind, opts...)
+	desc.config.InstrumentationName = m.name
+	desc.config.InstrumentationVersion = m.version
+	return m.impl.NewSyncInstrument(desc)
+}
+
+// MeterMust is a wrapper for Meter interfaces that panics when any
+// instrument constructor encounters an error.
+type MeterMust struct {
+	meter Meter
+}
+
+// BatchObserverMust is a wrapper for BatchObserver that panics when
+// any instrument constructor encounters an error.
+type BatchObserverMust struct {
+	batch BatchObserver
+}
+
+// Must constructs a MeterMust implementation from a Meter, allowing
+// the application to panic when any instrument constructor yields an
+// error.
+func Must(meter Meter) MeterMust {
+	return MeterMust{meter: meter}
+}
+
+// NewInt64Counter calls `Meter.NewInt64Counter` and returns the
+// instrument, panicking if it encounters an error.
+func (mm MeterMust) NewInt64Counter(name string, cos ...InstrumentOption) Int64Counter {
+	if inst, err := mm.meter.NewInt64Counter(name, cos...); err != nil {
+		panic(err)
+	} else {
+		return inst
+	}
+}
+
+// NewFloat64Counter calls `Meter.NewFloat64Counter` and returns the
+// instrument, panicking if it encounters an error.
+func (mm MeterMust) NewFloat64Counter(name string, cos ...InstrumentOption) Float64Counter {
+	if inst, err := mm.meter.NewFloat64Counter(name, cos...); err != nil {
+		panic(err)
+	} else {
+		return inst
+	}
+}
+
+// NewInt64UpDownCounter calls `Meter.NewInt64UpDownCounter` and returns the
+// instrument, panicking if it encounters an error.
+func (mm MeterMust) NewInt64UpDownCounter(name string, cos ...InstrumentOption) Int64UpDownCounter {
+	if inst, err := mm.meter.NewInt64UpDownCounter(name, cos...); err != nil {
+		panic(err)
+	} else {
+		return inst
+	}
+}
+
+// NewFloat64UpDownCounter calls `Meter.NewFloat64UpDownCounter` and returns the
+// instrument, panicking if it encounters an error.
+func (mm MeterMust) NewFloat64UpDownCounter(name string, cos ...InstrumentOption) Float64UpDownCounter {
+	if inst, err := mm.meter.NewFloat64UpDownCounter(name, cos...); err != nil {
+		panic(err)
+	} else {
+		return inst
+	}
+}
+
+// NewInt64ValueRecorder calls `Meter.NewInt64ValueRecorder` and returns the
+// instrument, panicking if it encounters an error.
+func (mm MeterMust) NewInt64ValueRecorder(name string, mos ...InstrumentOption) Int64ValueRecorder {
+	if inst, err := mm.meter.NewInt64ValueRecorder(name, mos...); err != nil {
+		panic(err)
+	} else {
+		return inst
+	}
+}
+
+// NewFloat64ValueRecorder calls `Meter.NewFloat64ValueRecorder` and returns the
+// instrument, panicking if it encounters an error.
+func (mm MeterMust) NewFloat64ValueRecorder(name string, mos ...InstrumentOption) Float64ValueRecorder {
+	if inst, err := mm.meter.NewFloat64ValueRecorder(name, mos...); err != nil {
+		panic(err)
+	} else {
+		return inst
+	}
+}
+
+// NewInt64ValueObserver calls `Meter.NewInt64ValueObserver` and
+// returns the instrument, panicking if it encounters an error.
+func (mm MeterMust) NewInt64ValueObserver(name string, callback Int64ObserverFunc, oos ...InstrumentOption) Int64ValueObserver {
+	if inst, err := mm.meter.NewInt64ValueObserver(name, callback, oos...); err != nil {
+		panic(err)
+	} else {
+		return inst
+	}
+}
+
+// NewFloat64ValueObserver calls `Meter.NewFloat64ValueObserver` and
+// returns the instrument, panicking if it encounters an error.
+func (mm MeterMust) NewFloat64ValueObserver(name string, callback Float64ObserverFunc, oos ...InstrumentOption) Float64ValueObserver {
+	if inst, err := mm.meter.NewFloat64ValueObserver(name, callback, oos...); err != nil {
+		panic(err)
+	} else {
+		return inst
+	}
+}
+
+// NewInt64SumObserver calls `Meter.NewInt64SumObserver` and
+// returns the instrument, panicking if it encounters an error.
+func (mm MeterMust) NewInt64SumObserver(name string, callback Int64ObserverFunc, oos ...InstrumentOption) Int64SumObserver {
+	if inst, err := mm.meter.NewInt64SumObserver(name, callback, oos...); err != nil {
+		panic(err)
+	} else {
+		return inst
+	}
+}
+
+// NewFloat64SumObserver calls `Meter.NewFloat64SumObserver` and
+// returns the instrument, panicking if it encounters an error.
+func (mm MeterMust) NewFloat64SumObserver(name string, callback Float64ObserverFunc, oos ...InstrumentOption) Float64SumObserver {
+	if inst, err := mm.meter.NewFloat64SumObserver(name, callback, oos...); err != nil {
+		panic(err)
+	} else {
+		return inst
+	}
+}
+
+// NewInt64UpDownSumObserver calls `Meter.NewInt64UpDownSumObserver` and
+// returns the instrument, panicking if it encounters an error.
+func (mm MeterMust) NewInt64UpDownSumObserver(name string, callback Int64ObserverFunc, oos ...InstrumentOption) Int64UpDownSumObserver {
+	if inst, err := mm.meter.NewInt64UpDownSumObserver(name, callback, oos...); err != nil {
+		panic(err)
+	} else {
+		return inst
+	}
+}
+
+// NewFloat64UpDownSumObserver calls `Meter.NewFloat64UpDownSumObserver` and
+// returns the instrument, panicking if it encounters an error.
+func (mm MeterMust) NewFloat64UpDownSumObserver(name string, callback Float64ObserverFunc, oos ...InstrumentOption) Float64UpDownSumObserver {
+	if inst, err := mm.meter.NewFloat64UpDownSumObserver(name, callback, oos...); err != nil {
+		panic(err)
+	} else {
+		return inst
+	}
+}
+
+// NewBatchObserver returns a wrapper around BatchObserver that panics
+// when any instrument constructor returns an error.
+func (mm MeterMust) NewBatchObserver(callback BatchObserverFunc) BatchObserverMust {
+	return BatchObserverMust{
+		batch: mm.meter.NewBatchObserver(callback),
+	}
+}
+
+// NewInt64ValueObserver calls `BatchObserver.NewInt64ValueObserver` and
+// returns the instrument, panicking if it encounters an error.
+func (bm BatchObserverMust) NewInt64ValueObserver(name string, oos ...InstrumentOption) Int64ValueObserver {
+	if inst, err := bm.batch.NewInt64ValueObserver(name, oos...); err != nil {
+		panic(err)
+	} else {
+		return inst
+	}
+}
+
+// NewFloat64ValueObserver calls `BatchObserver.NewFloat64ValueObserver` and
+// returns the instrument, panicking if it encounters an error.
+func (bm BatchObserverMust) NewFloat64ValueObserver(name string, oos ...InstrumentOption) Float64ValueObserver {
+	if inst, err := bm.batch.NewFloat64ValueObserver(name, oos...); err != nil {
+		panic(err)
+	} else {
+		return inst
+	}
+}
+
+// NewInt64SumObserver calls `BatchObserver.NewInt64SumObserver` and
+// returns the instrument, panicking if it encounters an error.
+func (bm BatchObserverMust) NewInt64SumObserver(name string, oos ...InstrumentOption) Int64SumObserver {
+	if inst, err := bm.batch.NewInt64SumObserver(name, oos...); err != nil {
+		panic(err)
+	} else {
+		return inst
+	}
+}
+
+// NewFloat64SumObserver calls `BatchObserver.NewFloat64SumObserver` and
+// returns the instrument, panicking if it encounters an error.
+func (bm BatchObserverMust) NewFloat64SumObserver(name string, oos ...InstrumentOption) Float64SumObserver {
+	if inst, err := bm.batch.NewFloat64SumObserver(name, oos...); err != nil {
+		panic(err)
+	} else {
+		return inst
+	}
+}
+
+// NewInt64UpDownSumObserver calls `BatchObserver.NewInt64UpDownSumObserver` and
+// returns the instrument, panicking if it encounters an error.
+func (bm BatchObserverMust) NewInt64UpDownSumObserver(name string, oos ...InstrumentOption) Int64UpDownSumObserver {
+	if inst, err := bm.batch.NewInt64UpDownSumObserver(name, oos...); err != nil {
+		panic(err)
+	} else {
+		return inst
+	}
+}
+
+// NewFloat64UpDownSumObserver calls `BatchObserver.NewFloat64UpDownSumObserver` and
+// returns the instrument, panicking if it encounters an error.
+func (bm BatchObserverMust) NewFloat64UpDownSumObserver(name string, oos ...InstrumentOption) Float64UpDownSumObserver {
+	if inst, err := bm.batch.NewFloat64UpDownSumObserver(name, oos...); err != nil {
+		panic(err)
+	} else {
+		return inst
+	}
+}
+
+// Descriptor contains all the settings that describe an instrument,
+// including its name, metric kind, number kind, and the configurable
+// options.
+type Descriptor struct {
+	name           string
+	instrumentKind InstrumentKind
+	numberKind     number.Kind
+	config         InstrumentConfig
+}
+
+// NewDescriptor returns a Descriptor with the given contents.
+func NewDescriptor(name string, ikind InstrumentKind, nkind number.Kind, opts ...InstrumentOption) Descriptor {
+	return Descriptor{
+		name:           name,
+		instrumentKind: ikind,
+		numberKind:     nkind,
+		config:         NewInstrumentConfig(opts...),
+	}
+}
+
+// Name returns the metric instrument's name.
+func (d Descriptor) Name() string {
+	return d.name
+}
+
+// InstrumentKind returns the specific kind of instrument.
+func (d Descriptor) InstrumentKind() InstrumentKind {
+	return d.instrumentKind
+}
+
+// Description provides a human-readable description of the metric
+// instrument.
+func (d Descriptor) Description() string {
+	return d.config.Description
+}
+
+// Unit describes the units of the metric instrument.  Unitless
+// metrics return the empty string.
+func (d Descriptor) Unit() unit.Unit {
+	return d.config.Unit
+}
+
+// NumberKind returns whether this instrument is declared over int64,
+// float64, or uint64 values.
+func (d Descriptor) NumberKind() number.Kind {
+	return d.numberKind
+}
+
+// InstrumentationName returns the name of the library that provided
+// instrumentation for this instrument.
+func (d Descriptor) InstrumentationName() string {
+	return d.config.InstrumentationName
+}
+
+// InstrumentationVersion returns the version of the library that provided
+// instrumentation for this instrument.
+func (d Descriptor) InstrumentationVersion() string {
+	return d.config.InstrumentationVersion
+}

vendor/go.opentelemetry.io/otel/metric/metric_instrument.go

@@ -0,0 +1,777 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//go:generate stringer -type=InstrumentKind
+
+package metric // import "go.opentelemetry.io/otel/metric"
+
+import (
+	"context"
+	"errors"
+
+	"go.opentelemetry.io/otel/attribute"
+	"go.opentelemetry.io/otel/metric/number"
+)
+
+// ErrSDKReturnedNilImpl is returned when a new `MeterImpl` returns nil.
+var ErrSDKReturnedNilImpl = errors.New("SDK returned a nil implementation")
+
+// InstrumentKind describes the kind of instrument.
+type InstrumentKind int8
+
+const (
+	// ValueRecorderInstrumentKind indicates a ValueRecorder instrument.
+	ValueRecorderInstrumentKind InstrumentKind = iota
+	// ValueObserverInstrumentKind indicates an ValueObserver instrument.
+	ValueObserverInstrumentKind
+
+	// CounterInstrumentKind indicates a Counter instrument.
+	CounterInstrumentKind
+	// UpDownCounterInstrumentKind indicates a UpDownCounter instrument.
+	UpDownCounterInstrumentKind
+
+	// SumObserverInstrumentKind indicates a SumObserver instrument.
+	SumObserverInstrumentKind
+	// UpDownSumObserverInstrumentKind indicates a UpDownSumObserver
+	// instrument.
+	UpDownSumObserverInstrumentKind
+)
+
+// Synchronous returns whether this is a synchronous kind of instrument.
+func (k InstrumentKind) Synchronous() bool {
+	switch k {
+	case CounterInstrumentKind, UpDownCounterInstrumentKind, ValueRecorderInstrumentKind:
+		return true
+	}
+	return false
+}
+
+// Asynchronous returns whether this is an asynchronous kind of instrument.
+func (k InstrumentKind) Asynchronous() bool {
+	return !k.Synchronous()
+}
+
+// Adding returns whether this kind of instrument adds its inputs (as opposed to Grouping).
+func (k InstrumentKind) Adding() bool {
+	switch k {
+	case CounterInstrumentKind, UpDownCounterInstrumentKind, SumObserverInstrumentKind, UpDownSumObserverInstrumentKind:
+		return true
+	}
+	return false
+}
+
+// Grouping returns whether this kind of instrument groups its inputs (as opposed to Adding).
+func (k InstrumentKind) Grouping() bool {
+	return !k.Adding()
+}
+
+// Monotonic returns whether this kind of instrument exposes a non-decreasing sum.
+func (k InstrumentKind) Monotonic() bool {
+	switch k {
+	case CounterInstrumentKind, SumObserverInstrumentKind:
+		return true
+	}
+	return false
+}
+
+// PrecomputedSum returns whether this kind of instrument receives precomputed sums.
+func (k InstrumentKind) PrecomputedSum() bool {
+	return k.Adding() && k.Asynchronous()
+}
+
+// Observation is used for reporting an asynchronous  batch of metric
+// values. Instances of this type should be created by asynchronous
+// instruments (e.g., Int64ValueObserver.Observation()).
+type Observation struct {
+	// number needs to be aligned for 64-bit atomic operations.
+	number     number.Number
+	instrument AsyncImpl
+}
+
+// Int64ObserverFunc is a type of callback that integral
+// observers run.
+type Int64ObserverFunc func(context.Context, Int64ObserverResult)
+
+// Float64ObserverFunc is a type of callback that floating point
+// observers run.
+type Float64ObserverFunc func(context.Context, Float64ObserverResult)
+
+// BatchObserverFunc is a callback argument for use with any
+// Observer instrument that will be reported as a batch of
+// observations.
+type BatchObserverFunc func(context.Context, BatchObserverResult)
+
+// Int64ObserverResult is passed to an observer callback to capture
+// observations for one asynchronous integer metric instrument.
+type Int64ObserverResult struct {
+	instrument AsyncImpl
+	function   func([]attribute.KeyValue, ...Observation)
+}
+
+// Float64ObserverResult is passed to an observer callback to capture
+// observations for one asynchronous floating point metric instrument.
+type Float64ObserverResult struct {
+	instrument AsyncImpl
+	function   func([]attribute.KeyValue, ...Observation)
+}
+
+// BatchObserverResult is passed to a batch observer callback to
+// capture observations for multiple asynchronous instruments.
+type BatchObserverResult struct {
+	function func([]attribute.KeyValue, ...Observation)
+}
+
+// Observe captures a single integer value from the associated
+// instrument callback, with the given labels.
+func (ir Int64ObserverResult) Observe(value int64, labels ...attribute.KeyValue) {
+	ir.function(labels, Observation{
+		instrument: ir.instrument,
+		number:     number.NewInt64Number(value),
+	})
+}
+
+// Observe captures a single floating point value from the associated
+// instrument callback, with the given labels.
+func (fr Float64ObserverResult) Observe(value float64, labels ...attribute.KeyValue) {
+	fr.function(labels, Observation{
+		instrument: fr.instrument,
+		number:     number.NewFloat64Number(value),
+	})
+}
+
+// Observe captures a multiple observations from the associated batch
+// instrument callback, with the given labels.
+func (br BatchObserverResult) Observe(labels []attribute.KeyValue, obs ...Observation) {
+	br.function(labels, obs...)
+}
+
+// AsyncRunner is expected to convert into an AsyncSingleRunner or an
+// AsyncBatchRunner.  SDKs will encounter an error if the AsyncRunner
+// does not satisfy one of these interfaces.
+type AsyncRunner interface {
+	// AnyRunner() is a non-exported method with no functional use
+	// other than to make this a non-empty interface.
+	AnyRunner()
+}
+
+// AsyncSingleRunner is an interface implemented by single-observer
+// callbacks.
+type AsyncSingleRunner interface {
+	// Run accepts a single instrument and function for capturing
+	// observations of that instrument.  Each call to the function
+	// receives one captured observation.  (The function accepts
+	// multiple observations so the same implementation can be
+	// used for batch runners.)
+	Run(ctx context.Context, single AsyncImpl, capture func([]attribute.KeyValue, ...Observation))
+
+	AsyncRunner
+}
+
+// AsyncBatchRunner is an interface implemented by batch-observer
+// callbacks.
+type AsyncBatchRunner interface {
+	// Run accepts a function for capturing observations of
+	// multiple instruments.
+	Run(ctx context.Context, capture func([]attribute.KeyValue, ...Observation))
+
+	AsyncRunner
+}
+
+var _ AsyncSingleRunner = (*Int64ObserverFunc)(nil)
+var _ AsyncSingleRunner = (*Float64ObserverFunc)(nil)
+var _ AsyncBatchRunner = (*BatchObserverFunc)(nil)
+
+// newInt64AsyncRunner returns a single-observer callback for integer Observer instruments.
+func newInt64AsyncRunner(c Int64ObserverFunc) AsyncSingleRunner {
+	return &c
+}
+
+// newFloat64AsyncRunner returns a single-observer callback for floating point Observer instruments.
+func newFloat64AsyncRunner(c Float64ObserverFunc) AsyncSingleRunner {
+	return &c
+}
+
+// newBatchAsyncRunner returns a batch-observer callback use with multiple Observer instruments.
+func newBatchAsyncRunner(c BatchObserverFunc) AsyncBatchRunner {
+	return &c
+}
+
+// AnyRunner implements AsyncRunner.
+func (*Int64ObserverFunc) AnyRunner() {}
+
+// AnyRunner implements AsyncRunner.
+func (*Float64ObserverFunc) AnyRunner() {}
+
+// AnyRunner implements AsyncRunner.
+func (*BatchObserverFunc) AnyRunner() {}
+
+// Run implements AsyncSingleRunner.
+func (i *Int64ObserverFunc) Run(ctx context.Context, impl AsyncImpl, function func([]attribute.KeyValue, ...Observation)) {
+	(*i)(ctx, Int64ObserverResult{
+		instrument: impl,
+		function:   function,
+	})
+}
+
+// Run implements AsyncSingleRunner.
+func (f *Float64ObserverFunc) Run(ctx context.Context, impl AsyncImpl, function func([]attribute.KeyValue, ...Observation)) {
+	(*f)(ctx, Float64ObserverResult{
+		instrument: impl,
+		function:   function,
+	})
+}
+
+// Run implements AsyncBatchRunner.
+func (b *BatchObserverFunc) Run(ctx context.Context, function func([]attribute.KeyValue, ...Observation)) {
+	(*b)(ctx, BatchObserverResult{
+		function: function,
+	})
+}
+
+// wrapInt64ValueObserverInstrument converts an AsyncImpl into Int64ValueObserver.
+func wrapInt64ValueObserverInstrument(asyncInst AsyncImpl, err error) (Int64ValueObserver, error) {
+	common, err := checkNewAsync(asyncInst, err)
+	return Int64ValueObserver{asyncInstrument: common}, err
+}
+
+// wrapFloat64ValueObserverInstrument converts an AsyncImpl into Float64ValueObserver.
+func wrapFloat64ValueObserverInstrument(asyncInst AsyncImpl, err error) (Float64ValueObserver, error) {
+	common, err := checkNewAsync(asyncInst, err)
+	return Float64ValueObserver{asyncInstrument: common}, err
+}
+
+// wrapInt64SumObserverInstrument converts an AsyncImpl into Int64SumObserver.
+func wrapInt64SumObserverInstrument(asyncInst AsyncImpl, err error) (Int64SumObserver, error) {
+	common, err := checkNewAsync(asyncInst, err)
+	return Int64SumObserver{asyncInstrument: common}, err
+}
+
+// wrapFloat64SumObserverInstrument converts an AsyncImpl into Float64SumObserver.
+func wrapFloat64SumObserverInstrument(asyncInst AsyncImpl, err error) (Float64SumObserver, error) {
+	common, err := checkNewAsync(asyncInst, err)
+	return Float64SumObserver{asyncInstrument: common}, err
+}
+
+// wrapInt64UpDownSumObserverInstrument converts an AsyncImpl into Int64UpDownSumObserver.
+func wrapInt64UpDownSumObserverInstrument(asyncInst AsyncImpl, err error) (Int64UpDownSumObserver, error) {
+	common, err := checkNewAsync(asyncInst, err)
+	return Int64UpDownSumObserver{asyncInstrument: common}, err
+}
+
+// wrapFloat64UpDownSumObserverInstrument converts an AsyncImpl into Float64UpDownSumObserver.
+func wrapFloat64UpDownSumObserverInstrument(asyncInst AsyncImpl, err error) (Float64UpDownSumObserver, error) {
+	common, err := checkNewAsync(asyncInst, err)
+	return Float64UpDownSumObserver{asyncInstrument: common}, err
+}
+
+// BatchObserver represents an Observer callback that can report
+// observations for multiple instruments.
+type BatchObserver struct {
+	meter  Meter
+	runner AsyncBatchRunner
+}
+
+// Int64ValueObserver is a metric that captures a set of int64 values at a
+// point in time.
+type Int64ValueObserver struct {
+	asyncInstrument
+}
+
+// Float64ValueObserver is a metric that captures a set of float64 values
+// at a point in time.
+type Float64ValueObserver struct {
+	asyncInstrument
+}
+
+// Int64SumObserver is a metric that captures a precomputed sum of
+// int64 values at a point in time.
+type Int64SumObserver struct {
+	asyncInstrument
+}
+
+// Float64SumObserver is a metric that captures a precomputed sum of
+// float64 values at a point in time.
+type Float64SumObserver struct {
+	asyncInstrument
+}
+
+// Int64UpDownSumObserver is a metric that captures a precomputed sum of
+// int64 values at a point in time.
+type Int64UpDownSumObserver struct {
+	asyncInstrument
+}
+
+// Float64UpDownSumObserver is a metric that captures a precomputed sum of
+// float64 values at a point in time.
+type Float64UpDownSumObserver struct {
+	asyncInstrument
+}
+
+// Observation returns an Observation, a BatchObserverFunc
+// argument, for an asynchronous integer instrument.
+// This returns an implementation-level object for use by the SDK,
+// users should not refer to this.
+func (i Int64ValueObserver) Observation(v int64) Observation {
+	return Observation{
+		number:     number.NewInt64Number(v),
+		instrument: i.instrument,
+	}
+}
+
+// Observation returns an Observation, a BatchObserverFunc
+// argument, for an asynchronous integer instrument.
+// This returns an implementation-level object for use by the SDK,
+// users should not refer to this.
+func (f Float64ValueObserver) Observation(v float64) Observation {
+	return Observation{
+		number:     number.NewFloat64Number(v),
+		instrument: f.instrument,
+	}
+}
+
+// Observation returns an Observation, a BatchObserverFunc
+// argument, for an asynchronous integer instrument.
+// This returns an implementation-level object for use by the SDK,
+// users should not refer to this.
+func (i Int64SumObserver) Observation(v int64) Observation {
+	return Observation{
+		number:     number.NewInt64Number(v),
+		instrument: i.instrument,
+	}
+}
+
+// Observation returns an Observation, a BatchObserverFunc
+// argument, for an asynchronous integer instrument.
+// This returns an implementation-level object for use by the SDK,
+// users should not refer to this.
+func (f Float64SumObserver) Observation(v float64) Observation {
+	return Observation{
+		number:     number.NewFloat64Number(v),
+		instrument: f.instrument,
+	}
+}
+
+// Observation returns an Observation, a BatchObserverFunc
+// argument, for an asynchronous integer instrument.
+// This returns an implementation-level object for use by the SDK,
+// users should not refer to this.
+func (i Int64UpDownSumObserver) Observation(v int64) Observation {
+	return Observation{
+		number:     number.NewInt64Number(v),
+		instrument: i.instrument,
+	}
+}
+
+// Observation returns an Observation, a BatchObserverFunc
+// argument, for an asynchronous integer instrument.
+// This returns an implementation-level object for use by the SDK,
+// users should not refer to this.
+func (f Float64UpDownSumObserver) Observation(v float64) Observation {
+	return Observation{
+		number:     number.NewFloat64Number(v),
+		instrument: f.instrument,
+	}
+}
+
+// Measurement is used for reporting a synchronous batch of metric
+// values. Instances of this type should be created by synchronous
+// instruments (e.g., Int64Counter.Measurement()).
+type Measurement struct {
+	// number needs to be aligned for 64-bit atomic operations.
+	number     number.Number
+	instrument SyncImpl
+}
+
+// syncInstrument contains a SyncImpl.
+type syncInstrument struct {
+	instrument SyncImpl
+}
+
+// syncBoundInstrument contains a BoundSyncImpl.
+type syncBoundInstrument struct {
+	boundInstrument BoundSyncImpl
+}
+
+// asyncInstrument contains a AsyncImpl.
+type asyncInstrument struct {
+	instrument AsyncImpl
+}
+
+// SyncImpl returns the instrument that created this measurement.
+// This returns an implementation-level object for use by the SDK,
+// users should not refer to this.
+func (m Measurement) SyncImpl() SyncImpl {
+	return m.instrument
+}
+
+// Number returns a number recorded in this measurement.
+func (m Measurement) Number() number.Number {
+	return m.number
+}
+
+// AsyncImpl returns the instrument that created this observation.
+// This returns an implementation-level object for use by the SDK,
+// users should not refer to this.
+func (m Observation) AsyncImpl() AsyncImpl {
+	return m.instrument
+}
+
+// Number returns a number recorded in this observation.
+func (m Observation) Number() number.Number {
+	return m.number
+}
+
+// AsyncImpl implements AsyncImpl.
+func (a asyncInstrument) AsyncImpl() AsyncImpl {
+	return a.instrument
+}
+
+// SyncImpl returns the implementation object for synchronous instruments.
+func (s syncInstrument) SyncImpl() SyncImpl {
+	return s.instrument
+}
+
+func (s syncInstrument) bind(labels []attribute.KeyValue) syncBoundInstrument {
+	return newSyncBoundInstrument(s.instrument.Bind(labels))
+}
+
+func (s syncInstrument) float64Measurement(value float64) Measurement {
+	return newMeasurement(s.instrument, number.NewFloat64Number(value))
+}
+
+func (s syncInstrument) int64Measurement(value int64) Measurement {
+	return newMeasurement(s.instrument, number.NewInt64Number(value))
+}
+
+func (s syncInstrument) directRecord(ctx context.Context, number number.Number, labels []attribute.KeyValue) {
+	s.instrument.RecordOne(ctx, number, labels)
+}
+
+func (h syncBoundInstrument) directRecord(ctx context.Context, number number.Number) {
+	h.boundInstrument.RecordOne(ctx, number)
+}
+
+// Unbind calls SyncImpl.Unbind.
+func (h syncBoundInstrument) Unbind() {
+	h.boundInstrument.Unbind()
+}
+
+// checkNewAsync receives an AsyncImpl and potential
+// error, and returns the same types, checking for and ensuring that
+// the returned interface is not nil.
+func checkNewAsync(instrument AsyncImpl, err error) (asyncInstrument, error) {
+	if instrument == nil {
+		if err == nil {
+			err = ErrSDKReturnedNilImpl
+		}
+		instrument = NoopAsync{}
+	}
+	return asyncInstrument{
+		instrument: instrument,
+	}, err
+}
+
+// checkNewSync receives an SyncImpl and potential
+// error, and returns the same types, checking for and ensuring that
+// the returned interface is not nil.
+func checkNewSync(instrument SyncImpl, err error) (syncInstrument, error) {
+	if instrument == nil {
+		if err == nil {
+			err = ErrSDKReturnedNilImpl
+		}
+		// Note: an alternate behavior would be to synthesize a new name
+		// or group all duplicately-named instruments of a certain type
+		// together and use a tag for the original name, e.g.,
+		//   name = 'invalid.counter.int64'
+		//   label = 'original-name=duplicate-counter-name'
+		instrument = NoopSync{}
+	}
+	return syncInstrument{
+		instrument: instrument,
+	}, err
+}
+
+func newSyncBoundInstrument(boundInstrument BoundSyncImpl) syncBoundInstrument {
+	return syncBoundInstrument{
+		boundInstrument: boundInstrument,
+	}
+}
+
+func newMeasurement(instrument SyncImpl, number number.Number) Measurement {
+	return Measurement{
+		instrument: instrument,
+		number:     number,
+	}
+}
+
+// wrapInt64CounterInstrument converts a SyncImpl into Int64Counter.
+func wrapInt64CounterInstrument(syncInst SyncImpl, err error) (Int64Counter, error) {
+	common, err := checkNewSync(syncInst, err)
+	return Int64Counter{syncInstrument: common}, err
+}
+
+// wrapFloat64CounterInstrument converts a SyncImpl into Float64Counter.
+func wrapFloat64CounterInstrument(syncInst SyncImpl, err error) (Float64Counter, error) {
+	common, err := checkNewSync(syncInst, err)
+	return Float64Counter{syncInstrument: common}, err
+}
+
+// wrapInt64UpDownCounterInstrument converts a SyncImpl into Int64UpDownCounter.
+func wrapInt64UpDownCounterInstrument(syncInst SyncImpl, err error) (Int64UpDownCounter, error) {
+	common, err := checkNewSync(syncInst, err)
+	return Int64UpDownCounter{syncInstrument: common}, err
+}
+
+// wrapFloat64UpDownCounterInstrument converts a SyncImpl into Float64UpDownCounter.
+func wrapFloat64UpDownCounterInstrument(syncInst SyncImpl, err error) (Float64UpDownCounter, error) {
+	common, err := checkNewSync(syncInst, err)
+	return Float64UpDownCounter{syncInstrument: common}, err
+}
+
+// wrapInt64ValueRecorderInstrument converts a SyncImpl into Int64ValueRecorder.
+func wrapInt64ValueRecorderInstrument(syncInst SyncImpl, err error) (Int64ValueRecorder, error) {
+	common, err := checkNewSync(syncInst, err)
+	return Int64ValueRecorder{syncInstrument: common}, err
+}
+
+// wrapFloat64ValueRecorderInstrument converts a SyncImpl into Float64ValueRecorder.
+func wrapFloat64ValueRecorderInstrument(syncInst SyncImpl, err error) (Float64ValueRecorder, error) {
+	common, err := checkNewSync(syncInst, err)
+	return Float64ValueRecorder{syncInstrument: common}, err
+}
+
+// Float64Counter is a metric that accumulates float64 values.
+type Float64Counter struct {
+	syncInstrument
+}
+
+// Int64Counter is a metric that accumulates int64 values.
+type Int64Counter struct {
+	syncInstrument
+}
+
+// BoundFloat64Counter is a bound instrument for Float64Counter.
+//
+// It inherits the Unbind function from syncBoundInstrument.
+type BoundFloat64Counter struct {
+	syncBoundInstrument
+}
+
+// BoundInt64Counter is a boundInstrument for Int64Counter.
+//
+// It inherits the Unbind function from syncBoundInstrument.
+type BoundInt64Counter struct {
+	syncBoundInstrument
+}
+
+// Bind creates a bound instrument for this counter. The labels are
+// associated with values recorded via subsequent calls to Record.
+func (c Float64Counter) Bind(labels ...attribute.KeyValue) (h BoundFloat64Counter) {
+	h.syncBoundInstrument = c.bind(labels)
+	return
+}
+
+// Bind creates a bound instrument for this counter. The labels are
+// associated with values recorded via subsequent calls to Record.
+func (c Int64Counter) Bind(labels ...attribute.KeyValue) (h BoundInt64Counter) {
+	h.syncBoundInstrument = c.bind(labels)
+	return
+}
+
+// Measurement creates a Measurement object to use with batch
+// recording.
+func (c Float64Counter) Measurement(value float64) Measurement {
+	return c.float64Measurement(value)
+}
+
+// Measurement creates a Measurement object to use with batch
+// recording.
+func (c Int64Counter) Measurement(value int64) Measurement {
+	return c.int64Measurement(value)
+}
+
+// Add adds the value to the counter's sum. The labels should contain
+// the keys and values to be associated with this value.
+func (c Float64Counter) Add(ctx context.Context, value float64, labels ...attribute.KeyValue) {
+	c.directRecord(ctx, number.NewFloat64Number(value), labels)
+}
+
+// Add adds the value to the counter's sum. The labels should contain
+// the keys and values to be associated with this value.
+func (c Int64Counter) Add(ctx context.Context, value int64, labels ...attribute.KeyValue) {
+	c.directRecord(ctx, number.NewInt64Number(value), labels)
+}
+
+// Add adds the value to the counter's sum using the labels
+// previously bound to this counter via Bind()
+func (b BoundFloat64Counter) Add(ctx context.Context, value float64) {
+	b.directRecord(ctx, number.NewFloat64Number(value))
+}
+
+// Add adds the value to the counter's sum using the labels
+// previously bound to this counter via Bind()
+func (b BoundInt64Counter) Add(ctx context.Context, value int64) {
+	b.directRecord(ctx, number.NewInt64Number(value))
+}
+
+// Float64UpDownCounter is a metric instrument that sums floating
+// point values.
+type Float64UpDownCounter struct {
+	syncInstrument
+}
+
+// Int64UpDownCounter is a metric instrument that sums integer values.
+type Int64UpDownCounter struct {
+	syncInstrument
+}
+
+// BoundFloat64UpDownCounter is a bound instrument for Float64UpDownCounter.
+//
+// It inherits the Unbind function from syncBoundInstrument.
+type BoundFloat64UpDownCounter struct {
+	syncBoundInstrument
+}
+
+// BoundInt64UpDownCounter is a boundInstrument for Int64UpDownCounter.
+//
+// It inherits the Unbind function from syncBoundInstrument.
+type BoundInt64UpDownCounter struct {
+	syncBoundInstrument
+}
+
+// Bind creates a bound instrument for this counter. The labels are
+// associated with values recorded via subsequent calls to Record.
+func (c Float64UpDownCounter) Bind(labels ...attribute.KeyValue) (h BoundFloat64UpDownCounter) {
+	h.syncBoundInstrument = c.bind(labels)
+	return
+}
+
+// Bind creates a bound instrument for this counter. The labels are
+// associated with values recorded via subsequent calls to Record.
+func (c Int64UpDownCounter) Bind(labels ...attribute.KeyValue) (h BoundInt64UpDownCounter) {
+	h.syncBoundInstrument = c.bind(labels)
+	return
+}
+
+// Measurement creates a Measurement object to use with batch
+// recording.
+func (c Float64UpDownCounter) Measurement(value float64) Measurement {
+	return c.float64Measurement(value)
+}
+
+// Measurement creates a Measurement object to use with batch
+// recording.
+func (c Int64UpDownCounter) Measurement(value int64) Measurement {
+	return c.int64Measurement(value)
+}
+
+// Add adds the value to the counter's sum. The labels should contain
+// the keys and values to be associated with this value.
+func (c Float64UpDownCounter) Add(ctx context.Context, value float64, labels ...attribute.KeyValue) {
+	c.directRecord(ctx, number.NewFloat64Number(value), labels)
+}
+
+// Add adds the value to the counter's sum. The labels should contain
+// the keys and values to be associated with this value.
+func (c Int64UpDownCounter) Add(ctx context.Context, value int64, labels ...attribute.KeyValue) {
+	c.directRecord(ctx, number.NewInt64Number(value), labels)
+}
+
+// Add adds the value to the counter's sum using the labels
+// previously bound to this counter via Bind()
+func (b BoundFloat64UpDownCounter) Add(ctx context.Context, value float64) {
+	b.directRecord(ctx, number.NewFloat64Number(value))
+}
+
+// Add adds the value to the counter's sum using the labels
+// previously bound to this counter via Bind()
+func (b BoundInt64UpDownCounter) Add(ctx context.Context, value int64) {
+	b.directRecord(ctx, number.NewInt64Number(value))
+}
+
+// Float64ValueRecorder is a metric that records float64 values.
+type Float64ValueRecorder struct {
+	syncInstrument
+}
+
+// Int64ValueRecorder is a metric that records int64 values.
+type Int64ValueRecorder struct {
+	syncInstrument
+}
+
+// BoundFloat64ValueRecorder is a bound instrument for Float64ValueRecorder.
+//
+// It inherits the Unbind function from syncBoundInstrument.
+type BoundFloat64ValueRecorder struct {
+	syncBoundInstrument
+}
+
+// BoundInt64ValueRecorder is a bound instrument for Int64ValueRecorder.
+//
+// It inherits the Unbind function from syncBoundInstrument.
+type BoundInt64ValueRecorder struct {
+	syncBoundInstrument
+}
+
+// Bind creates a bound instrument for this ValueRecorder. The labels are
+// associated with values recorded via subsequent calls to Record.
+func (c Float64ValueRecorder) Bind(labels ...attribute.KeyValue) (h BoundFloat64ValueRecorder) {
+	h.syncBoundInstrument = c.bind(labels)
+	return
+}
+
+// Bind creates a bound instrument for this ValueRecorder. The labels are
+// associated with values recorded via subsequent calls to Record.
+func (c Int64ValueRecorder) Bind(labels ...attribute.KeyValue) (h BoundInt64ValueRecorder) {
+	h.syncBoundInstrument = c.bind(labels)
+	return
+}
+
+// Measurement creates a Measurement object to use with batch
+// recording.
+func (c Float64ValueRecorder) Measurement(value float64) Measurement {
+	return c.float64Measurement(value)
+}
+
+// Measurement creates a Measurement object to use with batch
+// recording.
+func (c Int64ValueRecorder) Measurement(value int64) Measurement {
+	return c.int64Measurement(value)
+}
+
+// Record adds a new value to the list of ValueRecorder's records. The
+// labels should contain the keys and values to be associated with
+// this value.
+func (c Float64ValueRecorder) Record(ctx context.Context, value float64, labels ...attribute.KeyValue) {
+	c.directRecord(ctx, number.NewFloat64Number(value), labels)
+}
+
+// Record adds a new value to the ValueRecorder's distribution. The
+// labels should contain the keys and values to be associated with
+// this value.
+func (c Int64ValueRecorder) Record(ctx context.Context, value int64, labels ...attribute.KeyValue) {
+	c.directRecord(ctx, number.NewInt64Number(value), labels)
+}
+
+// Record adds a new value to the ValueRecorder's distribution using the labels
+// previously bound to the ValueRecorder via Bind().
+func (b BoundFloat64ValueRecorder) Record(ctx context.Context, value float64) {
+	b.directRecord(ctx, number.NewFloat64Number(value))
+}
+
+// Record adds a new value to the ValueRecorder's distribution using the labels
+// previously bound to the ValueRecorder via Bind().
+func (b BoundInt64ValueRecorder) Record(ctx context.Context, value int64) {
+	b.directRecord(ctx, number.NewInt64Number(value))
+}

vendor/go.opentelemetry.io/otel/metric/metric_noop.go

@@ -0,0 +1,59 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package metric // import "go.opentelemetry.io/otel/metric"
+
+import (
+	"context"
+
+	"go.opentelemetry.io/otel/attribute"
+	"go.opentelemetry.io/otel/metric/number"
+)
+
+type NoopMeterProvider struct{}
+
+type noopInstrument struct{}
+type noopBoundInstrument struct{}
+type NoopSync struct{ noopInstrument }
+type NoopAsync struct{ noopInstrument }
+
+var _ MeterProvider = NoopMeterProvider{}
+var _ SyncImpl = NoopSync{}
+var _ BoundSyncImpl = noopBoundInstrument{}
+var _ AsyncImpl = NoopAsync{}
+
+func (NoopMeterProvider) Meter(_ string, _ ...MeterOption) Meter {
+	return Meter{}
+}
+
+func (noopInstrument) Implementation() interface{} {
+	return nil
+}
+
+func (noopInstrument) Descriptor() Descriptor {
+	return Descriptor{}
+}
+
+func (noopBoundInstrument) RecordOne(context.Context, number.Number) {
+}
+
+func (noopBoundInstrument) Unbind() {
+}
+
+func (NoopSync) Bind([]attribute.KeyValue) BoundSyncImpl {
+	return noopBoundInstrument{}
+}
+
+func (NoopSync) RecordOne(context.Context, number.Number, []attribute.KeyValue) {
+}

vendor/go.opentelemetry.io/otel/metric/metric_sdkapi.go

@@ -0,0 +1,95 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package metric // import "go.opentelemetry.io/otel/metric"
+
+import (
+	"context"
+
+	"go.opentelemetry.io/otel/attribute"
+	"go.opentelemetry.io/otel/metric/number"
+)
+
+// MeterImpl is the interface an SDK must implement to supply a Meter
+// implementation.
+type MeterImpl interface {
+	// RecordBatch atomically records a batch of measurements.
+	RecordBatch(ctx context.Context, labels []attribute.KeyValue, measurement ...Measurement)
+
+	// NewSyncInstrument returns a newly constructed
+	// synchronous instrument implementation or an error, should
+	// one occur.
+	NewSyncInstrument(descriptor Descriptor) (SyncImpl, error)
+
+	// NewAsyncInstrument returns a newly constructed
+	// asynchronous instrument implementation or an error, should
+	// one occur.
+	NewAsyncInstrument(
+		descriptor Descriptor,
+		runner AsyncRunner,
+	) (AsyncImpl, error)
+}
+
+// InstrumentImpl is a common interface for synchronous and
+// asynchronous instruments.
+type InstrumentImpl interface {
+	// Implementation returns the underlying implementation of the
+	// instrument, which allows the implementation to gain access
+	// to its own representation especially from a `Measurement`.
+	Implementation() interface{}
+
+	// Descriptor returns a copy of the instrument's Descriptor.
+	Descriptor() Descriptor
+}
+
+// SyncImpl is the implementation-level interface to a generic
+// synchronous instrument (e.g., ValueRecorder and Counter instruments).
+type SyncImpl interface {
+	InstrumentImpl
+
+	// Bind creates an implementation-level bound instrument,
+	// binding a label set with this instrument implementation.
+	Bind(labels []attribute.KeyValue) BoundSyncImpl
+
+	// RecordOne captures a single synchronous metric event.
+	RecordOne(ctx context.Context, number number.Number, labels []attribute.KeyValue)
+}
+
+// BoundSyncImpl is the implementation-level interface to a
+// generic bound synchronous instrument
+type BoundSyncImpl interface {
+
+	// RecordOne captures a single synchronous metric event.
+	RecordOne(ctx context.Context, number number.Number)
+
+	// Unbind frees the resources associated with this bound instrument. It
+	// does not affect the metric this bound instrument was created through.
+	Unbind()
+}
+
+// AsyncImpl is an implementation-level interface to an
+// asynchronous instrument (e.g., Observer instruments).
+type AsyncImpl interface {
+	InstrumentImpl
+}
+
+// WrapMeterImpl constructs a `Meter` implementation from a
+// `MeterImpl` implementation.
+func WrapMeterImpl(impl MeterImpl, instrumentationName string, opts ...MeterOption) Meter {
+	return Meter{
+		impl:    impl,
+		name:    instrumentationName,
+		version: NewMeterConfig(opts...).InstrumentationVersion,
+	}
+}

vendor/go.opentelemetry.io/otel/metric/number/doc.go

@@ -0,0 +1,23 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+/*
+Package number provides a number abstraction for instruments that
+either support int64 or float64 input values.
+
+This package is currently in a pre-GA phase. Backwards incompatible changes
+may be introduced in subsequent minor version releases as we work to track the
+evolving OpenTelemetry specification and user feedback.
+*/
+package number // import "go.opentelemetry.io/otel/metric/number"

vendor/go.opentelemetry.io/otel/metric/number/kind_string.go

@@ -0,0 +1,24 @@
+// Code generated by "stringer -type=Kind"; DO NOT EDIT.
+
+package number
+
+import "strconv"
+
+func _() {
+	// An "invalid array index" compiler error signifies that the constant values have changed.
+	// Re-run the stringer command to generate them again.
+	var x [1]struct{}
+	_ = x[Int64Kind-0]
+	_ = x[Float64Kind-1]
+}
+
+const _Kind_name = "Int64KindFloat64Kind"
+
+var _Kind_index = [...]uint8{0, 9, 20}
+
+func (i Kind) String() string {
+	if i < 0 || i >= Kind(len(_Kind_index)-1) {
+		return "Kind(" + strconv.FormatInt(int64(i), 10) + ")"
+	}
+	return _Kind_name[_Kind_index[i]:_Kind_index[i+1]]
+}

vendor/go.opentelemetry.io/otel/metric/number/number.go

@@ -0,0 +1,538 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package number // import "go.opentelemetry.io/otel/metric/number"
+
+//go:generate stringer -type=Kind
+
+import (
+	"fmt"
+	"math"
+	"sync/atomic"
+
+	"go.opentelemetry.io/otel/internal"
+)
+
+// Kind describes the data type of the Number.
+type Kind int8
+
+const (
+	// Int64Kind means that the Number stores int64.
+	Int64Kind Kind = iota
+	// Float64Kind means that the Number stores float64.
+	Float64Kind
+)
+
+// Zero returns a zero value for a given Kind
+func (k Kind) Zero() Number {
+	switch k {
+	case Int64Kind:
+		return NewInt64Number(0)
+	case Float64Kind:
+		return NewFloat64Number(0.)
+	default:
+		return Number(0)
+	}
+}
+
+// Minimum returns the minimum representable value
+// for a given Kind
+func (k Kind) Minimum() Number {
+	switch k {
+	case Int64Kind:
+		return NewInt64Number(math.MinInt64)
+	case Float64Kind:
+		return NewFloat64Number(-1. * math.MaxFloat64)
+	default:
+		return Number(0)
+	}
+}
+
+// Maximum returns the maximum representable value
+// for a given Kind
+func (k Kind) Maximum() Number {
+	switch k {
+	case Int64Kind:
+		return NewInt64Number(math.MaxInt64)
+	case Float64Kind:
+		return NewFloat64Number(math.MaxFloat64)
+	default:
+		return Number(0)
+	}
+}
+
+// Number represents either an integral or a floating point value. It
+// needs to be accompanied with a source of Kind that describes
+// the actual type of the value stored within Number.
+type Number uint64
+
+// - constructors
+
+// NewNumberFromRaw creates a new Number from a raw value.
+func NewNumberFromRaw(r uint64) Number {
+	return Number(r)
+}
+
+// NewInt64Number creates an integral Number.
+func NewInt64Number(i int64) Number {
+	return NewNumberFromRaw(internal.Int64ToRaw(i))
+}
+
+// NewFloat64Number creates a floating point Number.
+func NewFloat64Number(f float64) Number {
+	return NewNumberFromRaw(internal.Float64ToRaw(f))
+}
+
+// NewNumberSignChange returns a number with the same magnitude and
+// the opposite sign.  `kind` must describe the kind of number in `nn`.
+func NewNumberSignChange(kind Kind, nn Number) Number {
+	switch kind {
+	case Int64Kind:
+		return NewInt64Number(-nn.AsInt64())
+	case Float64Kind:
+		return NewFloat64Number(-nn.AsFloat64())
+	}
+	return nn
+}
+
+// - as x
+
+// AsNumber gets the Number.
+func (n *Number) AsNumber() Number {
+	return *n
+}
+
+// AsRaw gets the uninterpreted raw value. Might be useful for some
+// atomic operations.
+func (n *Number) AsRaw() uint64 {
+	return uint64(*n)
+}
+
+// AsInt64 assumes that the value contains an int64 and returns it as
+// such.
+func (n *Number) AsInt64() int64 {
+	return internal.RawToInt64(n.AsRaw())
+}
+
+// AsFloat64 assumes that the measurement value contains a float64 and
+// returns it as such.
+func (n *Number) AsFloat64() float64 {
+	return internal.RawToFloat64(n.AsRaw())
+}
+
+// - as x atomic
+
+// AsNumberAtomic gets the Number atomically.
+func (n *Number) AsNumberAtomic() Number {
+	return NewNumberFromRaw(n.AsRawAtomic())
+}
+
+// AsRawAtomic gets the uninterpreted raw value atomically. Might be
+// useful for some atomic operations.
+func (n *Number) AsRawAtomic() uint64 {
+	return atomic.LoadUint64(n.AsRawPtr())
+}
+
+// AsInt64Atomic assumes that the number contains an int64 and returns
+// it as such atomically.
+func (n *Number) AsInt64Atomic() int64 {
+	return atomic.LoadInt64(n.AsInt64Ptr())
+}
+
+// AsFloat64Atomic assumes that the measurement value contains a
+// float64 and returns it as such atomically.
+func (n *Number) AsFloat64Atomic() float64 {
+	return internal.RawToFloat64(n.AsRawAtomic())
+}
+
+// - as x ptr
+
+// AsRawPtr gets the pointer to the raw, uninterpreted raw
+// value. Might be useful for some atomic operations.
+func (n *Number) AsRawPtr() *uint64 {
+	return (*uint64)(n)
+}
+
+// AsInt64Ptr assumes that the number contains an int64 and returns a
+// pointer to it.
+func (n *Number) AsInt64Ptr() *int64 {
+	return internal.RawPtrToInt64Ptr(n.AsRawPtr())
+}
+
+// AsFloat64Ptr assumes that the number contains a float64 and returns a
+// pointer to it.
+func (n *Number) AsFloat64Ptr() *float64 {
+	return internal.RawPtrToFloat64Ptr(n.AsRawPtr())
+}
+
+// - coerce
+
+// CoerceToInt64 casts the number to int64. May result in
+// data/precision loss.
+func (n *Number) CoerceToInt64(kind Kind) int64 {
+	switch kind {
+	case Int64Kind:
+		return n.AsInt64()
+	case Float64Kind:
+		return int64(n.AsFloat64())
+	default:
+		// you get what you deserve
+		return 0
+	}
+}
+
+// CoerceToFloat64 casts the number to float64. May result in
+// data/precision loss.
+func (n *Number) CoerceToFloat64(kind Kind) float64 {
+	switch kind {
+	case Int64Kind:
+		return float64(n.AsInt64())
+	case Float64Kind:
+		return n.AsFloat64()
+	default:
+		// you get what you deserve
+		return 0
+	}
+}
+
+// - set
+
+// SetNumber sets the number to the passed number. Both should be of
+// the same kind.
+func (n *Number) SetNumber(nn Number) {
+	*n.AsRawPtr() = nn.AsRaw()
+}
+
+// SetRaw sets the number to the passed raw value. Both number and the
+// raw number should represent the same kind.
+func (n *Number) SetRaw(r uint64) {
+	*n.AsRawPtr() = r
+}
+
+// SetInt64 assumes that the number contains an int64 and sets it to
+// the passed value.
+func (n *Number) SetInt64(i int64) {
+	*n.AsInt64Ptr() = i
+}
+
+// SetFloat64 assumes that the number contains a float64 and sets it
+// to the passed value.
+func (n *Number) SetFloat64(f float64) {
+	*n.AsFloat64Ptr() = f
+}
+
+// - set atomic
+
+// SetNumberAtomic sets the number to the passed number
+// atomically. Both should be of the same kind.
+func (n *Number) SetNumberAtomic(nn Number) {
+	atomic.StoreUint64(n.AsRawPtr(), nn.AsRaw())
+}
+
+// SetRawAtomic sets the number to the passed raw value
+// atomically. Both number and the raw number should represent the
+// same kind.
+func (n *Number) SetRawAtomic(r uint64) {
+	atomic.StoreUint64(n.AsRawPtr(), r)
+}
+
+// SetInt64Atomic assumes that the number contains an int64 and sets
+// it to the passed value atomically.
+func (n *Number) SetInt64Atomic(i int64) {
+	atomic.StoreInt64(n.AsInt64Ptr(), i)
+}
+
+// SetFloat64Atomic assumes that the number contains a float64 and
+// sets it to the passed value atomically.
+func (n *Number) SetFloat64Atomic(f float64) {
+	atomic.StoreUint64(n.AsRawPtr(), internal.Float64ToRaw(f))
+}
+
+// - swap
+
+// SwapNumber sets the number to the passed number and returns the old
+// number. Both this number and the passed number should be of the
+// same kind.
+func (n *Number) SwapNumber(nn Number) Number {
+	old := *n
+	n.SetNumber(nn)
+	return old
+}
+
+// SwapRaw sets the number to the passed raw value and returns the old
+// raw value. Both number and the raw number should represent the same
+// kind.
+func (n *Number) SwapRaw(r uint64) uint64 {
+	old := n.AsRaw()
+	n.SetRaw(r)
+	return old
+}
+
+// SwapInt64 assumes that the number contains an int64, sets it to the
+// passed value and returns the old int64 value.
+func (n *Number) SwapInt64(i int64) int64 {
+	old := n.AsInt64()
+	n.SetInt64(i)
+	return old
+}
+
+// SwapFloat64 assumes that the number contains an float64, sets it to
+// the passed value and returns the old float64 value.
+func (n *Number) SwapFloat64(f float64) float64 {
+	old := n.AsFloat64()
+	n.SetFloat64(f)
+	return old
+}
+
+// - swap atomic
+
+// SwapNumberAtomic sets the number to the passed number and returns
+// the old number atomically. Both this number and the passed number
+// should be of the same kind.
+func (n *Number) SwapNumberAtomic(nn Number) Number {
+	return NewNumberFromRaw(atomic.SwapUint64(n.AsRawPtr(), nn.AsRaw()))
+}
+
+// SwapRawAtomic sets the number to the passed raw value and returns
+// the old raw value atomically. Both number and the raw number should
+// represent the same kind.
+func (n *Number) SwapRawAtomic(r uint64) uint64 {
+	return atomic.SwapUint64(n.AsRawPtr(), r)
+}
+
+// SwapInt64Atomic assumes that the number contains an int64, sets it
+// to the passed value and returns the old int64 value atomically.
+func (n *Number) SwapInt64Atomic(i int64) int64 {
+	return atomic.SwapInt64(n.AsInt64Ptr(), i)
+}
+
+// SwapFloat64Atomic assumes that the number contains an float64, sets
+// it to the passed value and returns the old float64 value
+// atomically.
+func (n *Number) SwapFloat64Atomic(f float64) float64 {
+	return internal.RawToFloat64(atomic.SwapUint64(n.AsRawPtr(), internal.Float64ToRaw(f)))
+}
+
+// - add
+
+// AddNumber assumes that this and the passed number are of the passed
+// kind and adds the passed number to this number.
+func (n *Number) AddNumber(kind Kind, nn Number) {
+	switch kind {
+	case Int64Kind:
+		n.AddInt64(nn.AsInt64())
+	case Float64Kind:
+		n.AddFloat64(nn.AsFloat64())
+	}
+}
+
+// AddRaw assumes that this number and the passed raw value are of the
+// passed kind and adds the passed raw value to this number.
+func (n *Number) AddRaw(kind Kind, r uint64) {
+	n.AddNumber(kind, NewNumberFromRaw(r))
+}
+
+// AddInt64 assumes that the number contains an int64 and adds the
+// passed int64 to it.
+func (n *Number) AddInt64(i int64) {
+	*n.AsInt64Ptr() += i
+}
+
+// AddFloat64 assumes that the number contains a float64 and adds the
+// passed float64 to it.
+func (n *Number) AddFloat64(f float64) {
+	*n.AsFloat64Ptr() += f
+}
+
+// - add atomic
+
+// AddNumberAtomic assumes that this and the passed number are of the
+// passed kind and adds the passed number to this number atomically.
+func (n *Number) AddNumberAtomic(kind Kind, nn Number) {
+	switch kind {
+	case Int64Kind:
+		n.AddInt64Atomic(nn.AsInt64())
+	case Float64Kind:
+		n.AddFloat64Atomic(nn.AsFloat64())
+	}
+}
+
+// AddRawAtomic assumes that this number and the passed raw value are
+// of the passed kind and adds the passed raw value to this number
+// atomically.
+func (n *Number) AddRawAtomic(kind Kind, r uint64) {
+	n.AddNumberAtomic(kind, NewNumberFromRaw(r))
+}
+
+// AddInt64Atomic assumes that the number contains an int64 and adds
+// the passed int64 to it atomically.
+func (n *Number) AddInt64Atomic(i int64) {
+	atomic.AddInt64(n.AsInt64Ptr(), i)
+}
+
+// AddFloat64Atomic assumes that the number contains a float64 and
+// adds the passed float64 to it atomically.
+func (n *Number) AddFloat64Atomic(f float64) {
+	for {
+		o := n.AsFloat64Atomic()
+		if n.CompareAndSwapFloat64(o, o+f) {
+			break
+		}
+	}
+}
+
+// - compare and swap (atomic only)
+
+// CompareAndSwapNumber does the atomic CAS operation on this
+// number. This number and passed old and new numbers should be of the
+// same kind.
+func (n *Number) CompareAndSwapNumber(on, nn Number) bool {
+	return atomic.CompareAndSwapUint64(n.AsRawPtr(), on.AsRaw(), nn.AsRaw())
+}
+
+// CompareAndSwapRaw does the atomic CAS operation on this
+// number. This number and passed old and new raw values should be of
+// the same kind.
+func (n *Number) CompareAndSwapRaw(or, nr uint64) bool {
+	return atomic.CompareAndSwapUint64(n.AsRawPtr(), or, nr)
+}
+
+// CompareAndSwapInt64 assumes that this number contains an int64 and
+// does the atomic CAS operation on it.
+func (n *Number) CompareAndSwapInt64(oi, ni int64) bool {
+	return atomic.CompareAndSwapInt64(n.AsInt64Ptr(), oi, ni)
+}
+
+// CompareAndSwapFloat64 assumes that this number contains a float64 and
+// does the atomic CAS operation on it.
+func (n *Number) CompareAndSwapFloat64(of, nf float64) bool {
+	return atomic.CompareAndSwapUint64(n.AsRawPtr(), internal.Float64ToRaw(of), internal.Float64ToRaw(nf))
+}
+
+// - compare
+
+// CompareNumber compares two Numbers given their kind.  Both numbers
+// should have the same kind.  This returns:
+//    0 if the numbers are equal
+//    -1 if the subject `n` is less than the argument `nn`
+//    +1 if the subject `n` is greater than the argument `nn`
+func (n *Number) CompareNumber(kind Kind, nn Number) int {
+	switch kind {
+	case Int64Kind:
+		return n.CompareInt64(nn.AsInt64())
+	case Float64Kind:
+		return n.CompareFloat64(nn.AsFloat64())
+	default:
+		// you get what you deserve
+		return 0
+	}
+}
+
+// CompareRaw compares two numbers, where one is input as a raw
+// uint64, interpreting both values as a `kind` of number.
+func (n *Number) CompareRaw(kind Kind, r uint64) int {
+	return n.CompareNumber(kind, NewNumberFromRaw(r))
+}
+
+// CompareInt64 assumes that the Number contains an int64 and performs
+// a comparison between the value and the other value. It returns the
+// typical result of the compare function: -1 if the value is less
+// than the other, 0 if both are equal, 1 if the value is greater than
+// the other.
+func (n *Number) CompareInt64(i int64) int {
+	this := n.AsInt64()
+	if this < i {
+		return -1
+	} else if this > i {
+		return 1
+	}
+	return 0
+}
+
+// CompareFloat64 assumes that the Number contains a float64 and
+// performs a comparison between the value and the other value. It
+// returns the typical result of the compare function: -1 if the value
+// is less than the other, 0 if both are equal, 1 if the value is
+// greater than the other.
+//
+// Do not compare NaN values.
+func (n *Number) CompareFloat64(f float64) int {
+	this := n.AsFloat64()
+	if this < f {
+		return -1
+	} else if this > f {
+		return 1
+	}
+	return 0
+}
+
+// - relations to zero
+
+// IsPositive returns true if the actual value is greater than zero.
+func (n *Number) IsPositive(kind Kind) bool {
+	return n.compareWithZero(kind) > 0
+}
+
+// IsNegative returns true if the actual value is less than zero.
+func (n *Number) IsNegative(kind Kind) bool {
+	return n.compareWithZero(kind) < 0
+}
+
+// IsZero returns true if the actual value is equal to zero.
+func (n *Number) IsZero(kind Kind) bool {
+	return n.compareWithZero(kind) == 0
+}
+
+// - misc
+
+// Emit returns a string representation of the raw value of the
+// Number. A %d is used for integral values, %f for floating point
+// values.
+func (n *Number) Emit(kind Kind) string {
+	switch kind {
+	case Int64Kind:
+		return fmt.Sprintf("%d", n.AsInt64())
+	case Float64Kind:
+		return fmt.Sprintf("%f", n.AsFloat64())
+	default:
+		return ""
+	}
+}
+
+// AsInterface returns the number as an interface{}, typically used
+// for Kind-correct JSON conversion.
+func (n *Number) AsInterface(kind Kind) interface{} {
+	switch kind {
+	case Int64Kind:
+		return n.AsInt64()
+	case Float64Kind:
+		return n.AsFloat64()
+	default:
+		return math.NaN()
+	}
+}
+
+// - private stuff
+
+func (n *Number) compareWithZero(kind Kind) int {
+	switch kind {
+	case Int64Kind:
+		return n.CompareInt64(0)
+	case Float64Kind:
+		return n.CompareFloat64(0.)
+	default:
+		// you get what you deserve
+		return 0
+	}
+}

vendor/go.opentelemetry.io/otel/metric/registry/doc.go

@@ -0,0 +1,24 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+/*
+Package registry provides a non-standalone implementation of
+MeterProvider that adds uniqueness checking for instrument descriptors
+on top of other MeterProvider it wraps.
+
+This package is currently in a pre-GA phase. Backwards incompatible changes
+may be introduced in subsequent minor version releases as we work to track the
+evolving OpenTelemetry specification and user feedback.
+*/
+package registry // import "go.opentelemetry.io/otel/metric/registry"

vendor/go.opentelemetry.io/otel/metric/registry/registry.go

@@ -0,0 +1,170 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package registry // import "go.opentelemetry.io/otel/metric/registry"
+
+import (
+	"context"
+	"fmt"
+	"sync"
+
+	"go.opentelemetry.io/otel/attribute"
+	"go.opentelemetry.io/otel/metric"
+)
+
+// MeterProvider is a standard MeterProvider for wrapping `MeterImpl`
+type MeterProvider struct {
+	impl metric.MeterImpl
+}
+
+var _ metric.MeterProvider = (*MeterProvider)(nil)
+
+// uniqueInstrumentMeterImpl implements the metric.MeterImpl interface, adding
+// uniqueness checking for instrument descriptors.  Use NewUniqueInstrumentMeter
+// to wrap an implementation with uniqueness checking.
+type uniqueInstrumentMeterImpl struct {
+	lock  sync.Mutex
+	impl  metric.MeterImpl
+	state map[key]metric.InstrumentImpl
+}
+
+var _ metric.MeterImpl = (*uniqueInstrumentMeterImpl)(nil)
+
+type key struct {
+	instrumentName         string
+	instrumentationName    string
+	InstrumentationVersion string
+}
+
+// NewMeterProvider returns a new provider that implements instrument
+// name-uniqueness checking.
+func NewMeterProvider(impl metric.MeterImpl) *MeterProvider {
+	return &MeterProvider{
+		impl: NewUniqueInstrumentMeterImpl(impl),
+	}
+}
+
+// Meter implements MeterProvider.
+func (p *MeterProvider) Meter(instrumentationName string, opts ...metric.MeterOption) metric.Meter {
+	return metric.WrapMeterImpl(p.impl, instrumentationName, opts...)
+}
+
+// ErrMetricKindMismatch is the standard error for mismatched metric
+// instrument definitions.
+var ErrMetricKindMismatch = fmt.Errorf(
+	"a metric was already registered by this name with another kind or number type")
+
+// NewUniqueInstrumentMeterImpl returns a wrapped metric.MeterImpl with
+// the addition of uniqueness checking.
+func NewUniqueInstrumentMeterImpl(impl metric.MeterImpl) metric.MeterImpl {
+	return &uniqueInstrumentMeterImpl{
+		impl:  impl,
+		state: map[key]metric.InstrumentImpl{},
+	}
+}
+
+// RecordBatch implements metric.MeterImpl.
+func (u *uniqueInstrumentMeterImpl) RecordBatch(ctx context.Context, labels []attribute.KeyValue, ms ...metric.Measurement) {
+	u.impl.RecordBatch(ctx, labels, ms...)
+}
+
+func keyOf(descriptor metric.Descriptor) key {
+	return key{
+		descriptor.Name(),
+		descriptor.InstrumentationName(),
+		descriptor.InstrumentationVersion(),
+	}
+}
+
+// NewMetricKindMismatchError formats an error that describes a
+// mismatched metric instrument definition.
+func NewMetricKindMismatchError(desc metric.Descriptor) error {
+	return fmt.Errorf("metric was %s (%s %s)registered as a %s %s: %w",
+		desc.Name(),
+		desc.InstrumentationName(),
+		desc.InstrumentationVersion(),
+		desc.NumberKind(),
+		desc.InstrumentKind(),
+		ErrMetricKindMismatch)
+}
+
+// Compatible determines whether two metric.Descriptors are considered
+// the same for the purpose of uniqueness checking.
+func Compatible(candidate, existing metric.Descriptor) bool {
+	return candidate.InstrumentKind() == existing.InstrumentKind() &&
+		candidate.NumberKind() == existing.NumberKind()
+}
+
+// checkUniqueness returns an ErrMetricKindMismatch error if there is
+// a conflict between a descriptor that was already registered and the
+// `descriptor` argument.  If there is an existing compatible
+// registration, this returns the already-registered instrument.  If
+// there is no conflict and no prior registration, returns (nil, nil).
+func (u *uniqueInstrumentMeterImpl) checkUniqueness(descriptor metric.Descriptor) (metric.InstrumentImpl, error) {
+	impl, ok := u.state[keyOf(descriptor)]
+	if !ok {
+		return nil, nil
+	}
+
+	if !Compatible(descriptor, impl.Descriptor()) {
+		return nil, NewMetricKindMismatchError(impl.Descriptor())
+	}
+
+	return impl, nil
+}
+
+// NewSyncInstrument implements metric.MeterImpl.
+func (u *uniqueInstrumentMeterImpl) NewSyncInstrument(descriptor metric.Descriptor) (metric.SyncImpl, error) {
+	u.lock.Lock()
+	defer u.lock.Unlock()
+
+	impl, err := u.checkUniqueness(descriptor)
+
+	if err != nil {
+		return nil, err
+	} else if impl != nil {
+		return impl.(metric.SyncImpl), nil
+	}
+
+	syncInst, err := u.impl.NewSyncInstrument(descriptor)
+	if err != nil {
+		return nil, err
+	}
+	u.state[keyOf(descriptor)] = syncInst
+	return syncInst, nil
+}
+
+// NewAsyncInstrument implements metric.MeterImpl.
+func (u *uniqueInstrumentMeterImpl) NewAsyncInstrument(
+	descriptor metric.Descriptor,
+	runner metric.AsyncRunner,
+) (metric.AsyncImpl, error) {
+	u.lock.Lock()
+	defer u.lock.Unlock()
+
+	impl, err := u.checkUniqueness(descriptor)
+
+	if err != nil {
+		return nil, err
+	} else if impl != nil {
+		return impl.(metric.AsyncImpl), nil
+	}
+
+	asyncInst, err := u.impl.NewAsyncInstrument(descriptor, runner)
+	if err != nil {
+		return nil, err
+	}
+	u.state[keyOf(descriptor)] = asyncInst
+	return asyncInst, nil
+}

vendor/go.opentelemetry.io/otel/pre_release.sh

@@ -0,0 +1,95 @@
+#!/bin/bash
+
+# Copyright The OpenTelemetry Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+set -e
+
+help()
+{
+   printf "\n"
+   printf "Usage: $0 -t tag\n"
+   printf "\t-t Unreleased tag. Update all go.mod with this tag.\n"
+   exit 1 # Exit script after printing help
+}
+
+while getopts "t:" opt
+do
+   case "$opt" in
+      t ) TAG="$OPTARG" ;;
+      ? ) help ;; # Print help
+   esac
+done
+
+# Print help in case parameters are empty
+if [ -z "$TAG" ]
+then
+   printf "Tag is missing\n";
+   help
+fi
+
+# Validate semver
+SEMVER_REGEX="^v(0|[1-9][0-9]*)\\.(0|[1-9][0-9]*)\\.(0|[1-9][0-9]*)(\\-[0-9A-Za-z-]+(\\.[0-9A-Za-z-]+)*)?(\\+[0-9A-Za-z-]+(\\.[0-9A-Za-z-]+)*)?$"
+if [[ "${TAG}" =~ ${SEMVER_REGEX} ]]; then
+	printf "${TAG} is valid semver tag.\n"
+else
+	printf "${TAG} is not a valid semver tag.\n"
+	exit -1
+fi
+
+TAG_FOUND=`git tag --list ${TAG}`
+if [[ ${TAG_FOUND} = ${TAG} ]] ; then
+        printf "Tag ${TAG} already exists\n"
+        exit -1
+fi
+
+# Get version for version.go
+OTEL_VERSION=$(echo "${TAG}" | grep -o '^v[0-9]\+\.[0-9]\+\.[0-9]\+')
+# Strip leading v
+OTEL_VERSION="${OTEL_VERSION#v}"
+
+cd $(dirname $0)
+
+if ! git diff --quiet; then \
+	printf "Working tree is not clean, can't proceed with the release process\n"
+	git status
+	git diff
+	exit 1
+fi
+
+# Update version.go
+cp ./version.go ./version.go.bak
+sed "s/\(return \"\)[0-9]*\.[0-9]*\.[0-9]*\"/\1${OTEL_VERSION}\"/" ./version.go.bak >./version.go
+rm -f ./version.go.bak
+
+# Update go.mod
+git checkout -b pre_release_${TAG} main
+PACKAGE_DIRS=$(find . -mindepth 2 -type f -name 'go.mod' -exec dirname {} \; | egrep -v 'tools' | sed 's/^\.\///' | sort)
+
+for dir in $PACKAGE_DIRS; do
+	cp "${dir}/go.mod" "${dir}/go.mod.bak"
+	sed "s/opentelemetry.io\/otel\([^ ]*\) v[0-9]*\.[0-9]*\.[0-9]/opentelemetry.io\/otel\1 ${TAG}/" "${dir}/go.mod.bak" >"${dir}/go.mod"
+	rm -f "${dir}/go.mod.bak"
+done
+
+# Run lint to update go.sum
+make lint
+
+# Add changes and commit.
+git add .
+make ci
+git commit -m "Prepare for releasing $TAG"
+
+printf "Now run following to verify the changes.\ngit diff main\n"
+printf "\nThen push the changes to upstream\n"

vendor/go.opentelemetry.io/otel/propagation.go

@@ -0,0 +1,31 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package otel // import "go.opentelemetry.io/otel"
+
+import (
+	"go.opentelemetry.io/otel/internal/global"
+	"go.opentelemetry.io/otel/propagation"
+)
+
+// GetTextMapPropagator returns the global TextMapPropagator. If none has been
+// set, a No-Op TextMapPropagator is returned.
+func GetTextMapPropagator() propagation.TextMapPropagator {
+	return global.TextMapPropagator()
+}
+
+// SetTextMapPropagator sets propagator as the global TextMapPropagator.
+func SetTextMapPropagator(propagator propagation.TextMapPropagator) {
+	global.SetTextMapPropagator(propagator)
+}

vendor/go.opentelemetry.io/otel/propagation/baggage.go

@@ -0,0 +1,111 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package propagation // import "go.opentelemetry.io/otel/propagation"
+
+import (
+	"context"
+	"net/url"
+	"strings"
+
+	"go.opentelemetry.io/otel/attribute"
+	"go.opentelemetry.io/otel/internal/baggage"
+)
+
+const baggageHeader = "baggage"
+
+// Baggage is a propagator that supports the W3C Baggage format.
+//
+// This propagates user-defined baggage associated with a trace. The complete
+// specification is defined at https://w3c.github.io/baggage/.
+type Baggage struct{}
+
+var _ TextMapPropagator = Baggage{}
+
+// Inject sets baggage key-values from ctx into the carrier.
+func (b Baggage) Inject(ctx context.Context, carrier TextMapCarrier) {
+	baggageMap := baggage.MapFromContext(ctx)
+	firstIter := true
+	var headerValueBuilder strings.Builder
+	baggageMap.Foreach(func(kv attribute.KeyValue) bool {
+		if !firstIter {
+			headerValueBuilder.WriteRune(',')
+		}
+		firstIter = false
+		headerValueBuilder.WriteString(url.QueryEscape(strings.TrimSpace((string)(kv.Key))))
+		headerValueBuilder.WriteRune('=')
+		headerValueBuilder.WriteString(url.QueryEscape(strings.TrimSpace(kv.Value.Emit())))
+		return true
+	})
+	if headerValueBuilder.Len() > 0 {
+		headerString := headerValueBuilder.String()
+		carrier.Set(baggageHeader, headerString)
+	}
+}
+
+// Extract returns a copy of parent with the baggage from the carrier added.
+func (b Baggage) Extract(parent context.Context, carrier TextMapCarrier) context.Context {
+	bVal := carrier.Get(baggageHeader)
+	if bVal == "" {
+		return parent
+	}
+
+	baggageValues := strings.Split(bVal, ",")
+	keyValues := make([]attribute.KeyValue, 0, len(baggageValues))
+	for _, baggageValue := range baggageValues {
+		valueAndProps := strings.Split(baggageValue, ";")
+		if len(valueAndProps) < 1 {
+			continue
+		}
+		nameValue := strings.Split(valueAndProps[0], "=")
+		if len(nameValue) < 2 {
+			continue
+		}
+		name, err := url.QueryUnescape(nameValue[0])
+		if err != nil {
+			continue
+		}
+		trimmedName := strings.TrimSpace(name)
+		value, err := url.QueryUnescape(nameValue[1])
+		if err != nil {
+			continue
+		}
+		trimmedValue := strings.TrimSpace(value)
+
+		// TODO (skaris): properties defiend https://w3c.github.io/correlation-context/, are currently
+		// just put as part of the value.
+		var trimmedValueWithProps strings.Builder
+		trimmedValueWithProps.WriteString(trimmedValue)
+		for _, prop := range valueAndProps[1:] {
+			trimmedValueWithProps.WriteRune(';')
+			trimmedValueWithProps.WriteString(prop)
+		}
+
+		keyValues = append(keyValues, attribute.String(trimmedName, trimmedValueWithProps.String()))
+	}
+
+	if len(keyValues) > 0 {
+		// Only update the context if valid values were found
+		return baggage.ContextWithMap(parent, baggage.NewMap(baggage.MapUpdate{
+			MultiKV: keyValues,
+		}))
+	}
+
+	return parent
+}
+
+// Fields returns the keys who's values are set with Inject.
+func (b Baggage) Fields() []string {
+	return []string{baggageHeader}
+}

vendor/go.opentelemetry.io/otel/propagation/doc.go

@@ -0,0 +1,28 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+/*
+Package propagation contains OpenTelemetry context propagators.
+
+This package is currently in a pre-GA phase. Backwards incompatible changes
+may be introduced in subsequent minor version releases as we work to track the
+evolving OpenTelemetry specification and user feedback.
+
+OpenTelemetry propagators are used to extract and inject context data from and
+into messages exchanged by applications. The propagator supported by this
+package is the W3C Trace Context encoding
+(https://www.w3.org/TR/trace-context/), and W3C Baggage
+(https://w3c.github.io/baggage/).
+*/
+package propagation // import "go.opentelemetry.io/otel/propagation"

vendor/go.opentelemetry.io/otel/propagation/propagation.go

@@ -0,0 +1,105 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package propagation // import "go.opentelemetry.io/otel/propagation"
+
+import (
+	"context"
+	"net/http"
+)
+
+// TextMapCarrier is the storage medium used by a TextMapPropagator.
+type TextMapCarrier interface {
+	// Get returns the value associated with the passed key.
+	Get(key string) string
+	// Set stores the key-value pair.
+	Set(key string, value string)
+	// Keys lists the keys stored in this carrier.
+	Keys() []string
+}
+
+// HeaderCarrier adapts http.Header to satisfy the TextMapCarrier interface.
+type HeaderCarrier http.Header
+
+// Get returns the value associated with the passed key.
+func (hc HeaderCarrier) Get(key string) string {
+	return http.Header(hc).Get(key)
+}
+
+// Set stores the key-value pair.
+func (hc HeaderCarrier) Set(key string, value string) {
+	http.Header(hc).Set(key, value)
+}
+
+// Keys lists the keys stored in this carrier.
+func (hc HeaderCarrier) Keys() []string {
+	keys := make([]string, 0, len(hc))
+	for k := range hc {
+		keys = append(keys, k)
+	}
+	return keys
+}
+
+// TextMapPropagator propagates cross-cutting concerns as key-value text
+// pairs within a carrier that travels in-band across process boundaries.
+type TextMapPropagator interface {
+	// Inject set cross-cutting concerns from the Context into the carrier.
+	Inject(ctx context.Context, carrier TextMapCarrier)
+	// Extract reads cross-cutting concerns from the carrier into a Context.
+	Extract(ctx context.Context, carrier TextMapCarrier) context.Context
+	// Fields returns the keys who's values are set with Inject.
+	Fields() []string
+}
+
+type compositeTextMapPropagator []TextMapPropagator
+
+func (p compositeTextMapPropagator) Inject(ctx context.Context, carrier TextMapCarrier) {
+	for _, i := range p {
+		i.Inject(ctx, carrier)
+	}
+}
+
+func (p compositeTextMapPropagator) Extract(ctx context.Context, carrier TextMapCarrier) context.Context {
+	for _, i := range p {
+		ctx = i.Extract(ctx, carrier)
+	}
+	return ctx
+}
+
+func (p compositeTextMapPropagator) Fields() []string {
+	unique := make(map[string]struct{})
+	for _, i := range p {
+		for _, k := range i.Fields() {
+			unique[k] = struct{}{}
+		}
+	}
+
+	fields := make([]string, 0, len(unique))
+	for k := range unique {
+		fields = append(fields, k)
+	}
+	return fields
+}
+
+// NewCompositeTextMapPropagator returns a unified TextMapPropagator from the
+// group of passed TextMapPropagator. This allows different cross-cutting
+// concerns to be propagates in a unified manner.
+//
+// The returned TextMapPropagator will inject and extract cross-cutting
+// concerns in the order the TextMapPropagators were provided. Additionally,
+// the Fields method will return a de-duplicated slice of the keys that are
+// set with the Inject method.
+func NewCompositeTextMapPropagator(p ...TextMapPropagator) TextMapPropagator {
+	return compositeTextMapPropagator(p)
+}

vendor/go.opentelemetry.io/otel/propagation/trace_context.go

@@ -0,0 +1,178 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package propagation // import "go.opentelemetry.io/otel/propagation"
+
+import (
+	"context"
+	"encoding/hex"
+	"fmt"
+	"regexp"
+	"strings"
+
+	"go.opentelemetry.io/otel/attribute"
+	"go.opentelemetry.io/otel/trace"
+)
+
+const (
+	supportedVersion  = 0
+	maxVersion        = 254
+	traceparentHeader = "traceparent"
+	tracestateHeader  = "tracestate"
+)
+
+// TraceContext is a propagator that supports the W3C Trace Context format
+// (https://www.w3.org/TR/trace-context/)
+//
+// This propagator will propagate the traceparent and tracestate headers to
+// guarantee traces are not broken. It is up to the users of this propagator
+// to choose if they want to participate in a trace by modifying the
+// traceparent header and relevant parts of the tracestate header containing
+// their proprietary information.
+type TraceContext struct{}
+
+var _ TextMapPropagator = TraceContext{}
+var traceCtxRegExp = regexp.MustCompile("^(?P<version>[0-9a-f]{2})-(?P<traceID>[a-f0-9]{32})-(?P<spanID>[a-f0-9]{16})-(?P<traceFlags>[a-f0-9]{2})(?:-.*)?$")
+
+// Inject set tracecontext from the Context into the carrier.
+func (tc TraceContext) Inject(ctx context.Context, carrier TextMapCarrier) {
+	sc := trace.SpanContextFromContext(ctx)
+	if !sc.IsValid() {
+		return
+	}
+
+	carrier.Set(tracestateHeader, sc.TraceState().String())
+
+	// Clear all flags other than the trace-context supported sampling bit.
+	flags := sc.TraceFlags() & trace.FlagsSampled
+
+	h := fmt.Sprintf("%.2x-%s-%s-%s",
+		supportedVersion,
+		sc.TraceID(),
+		sc.SpanID(),
+		flags)
+	carrier.Set(traceparentHeader, h)
+}
+
+// Extract reads tracecontext from the carrier into a returned Context.
+//
+// The returned Context will be a copy of ctx and contain the extracted
+// tracecontext as the remote SpanContext. If the extracted tracecontext is
+// invalid, the passed ctx will be returned directly instead.
+func (tc TraceContext) Extract(ctx context.Context, carrier TextMapCarrier) context.Context {
+	sc := tc.extract(carrier)
+	if !sc.IsValid() {
+		return ctx
+	}
+	return trace.ContextWithRemoteSpanContext(ctx, sc)
+}
+
+func (tc TraceContext) extract(carrier TextMapCarrier) trace.SpanContext {
+	h := carrier.Get(traceparentHeader)
+	if h == "" {
+		return trace.SpanContext{}
+	}
+
+	matches := traceCtxRegExp.FindStringSubmatch(h)
+
+	if len(matches) == 0 {
+		return trace.SpanContext{}
+	}
+
+	if len(matches) < 5 { // four subgroups plus the overall match
+		return trace.SpanContext{}
+	}
+
+	if len(matches[1]) != 2 {
+		return trace.SpanContext{}
+	}
+	ver, err := hex.DecodeString(matches[1])
+	if err != nil {
+		return trace.SpanContext{}
+	}
+	version := int(ver[0])
+	if version > maxVersion {
+		return trace.SpanContext{}
+	}
+
+	if version == 0 && len(matches) != 5 { // four subgroups plus the overall match
+		return trace.SpanContext{}
+	}
+
+	if len(matches[2]) != 32 {
+		return trace.SpanContext{}
+	}
+
+	var scc trace.SpanContextConfig
+
+	scc.TraceID, err = trace.TraceIDFromHex(matches[2][:32])
+	if err != nil {
+		return trace.SpanContext{}
+	}
+
+	if len(matches[3]) != 16 {
+		return trace.SpanContext{}
+	}
+	scc.SpanID, err = trace.SpanIDFromHex(matches[3])
+	if err != nil {
+		return trace.SpanContext{}
+	}
+
+	if len(matches[4]) != 2 {
+		return trace.SpanContext{}
+	}
+	opts, err := hex.DecodeString(matches[4])
+	if err != nil || len(opts) < 1 || (version == 0 && opts[0] > 2) {
+		return trace.SpanContext{}
+	}
+	// Clear all flags other than the trace-context supported sampling bit.
+	scc.TraceFlags = trace.TraceFlags(opts[0]) & trace.FlagsSampled
+
+	scc.TraceState = parseTraceState(carrier.Get(tracestateHeader))
+	scc.Remote = true
+
+	sc := trace.NewSpanContext(scc)
+	if !sc.IsValid() {
+		return trace.SpanContext{}
+	}
+
+	return sc
+}
+
+// Fields returns the keys who's values are set with Inject.
+func (tc TraceContext) Fields() []string {
+	return []string{traceparentHeader, tracestateHeader}
+}
+
+func parseTraceState(in string) trace.TraceState {
+	if in == "" {
+		return trace.TraceState{}
+	}
+
+	kvs := []attribute.KeyValue{}
+	for _, entry := range strings.Split(in, ",") {
+		parts := strings.SplitN(entry, "=", 2)
+		if len(parts) != 2 {
+			// Parse failure, abort!
+			return trace.TraceState{}
+		}
+		kvs = append(kvs, attribute.String(parts[0], parts[1]))
+	}
+
+	// Ignoring error here as "failure to parse tracestate MUST NOT
+	// affect the parsing of traceparent."
+	// https://www.w3.org/TR/trace-context/#tracestate-header
+	ts, _ := trace.TraceStateFromKeyValues(kvs...)
+	return ts
+}

vendor/go.opentelemetry.io/otel/sdk/LICENSE

@@ -0,0 +1,201 @@
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.

vendor/go.opentelemetry.io/otel/sdk/export/metric/LICENSE

@@ -0,0 +1,201 @@
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.

vendor/go.opentelemetry.io/otel/sdk/export/metric/aggregation/aggregation.go

@@ -0,0 +1,154 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package aggregation // import "go.opentelemetry.io/otel/sdk/export/metric/aggregation"
+
+import (
+	"fmt"
+	"time"
+
+	"go.opentelemetry.io/otel/metric/number"
+)
+
+// These interfaces describe the various ways to access state from an
+// Aggregation.
+
+type (
+	// Aggregation is an interface returned by the Aggregator
+	// containing an interval of metric data.
+	Aggregation interface {
+		// Kind returns a short identifying string to identify
+		// the Aggregator that was used to produce the
+		// Aggregation (e.g., "Sum").
+		Kind() Kind
+	}
+
+	// Sum returns an aggregated sum.
+	Sum interface {
+		Aggregation
+		Sum() (number.Number, error)
+	}
+
+	// Count returns the number of values that were aggregated.
+	Count interface {
+		Aggregation
+		Count() (uint64, error)
+	}
+
+	// Min returns the minimum value over the set of values that were aggregated.
+	Min interface {
+		Aggregation
+		Min() (number.Number, error)
+	}
+
+	// Max returns the maximum value over the set of values that were aggregated.
+	Max interface {
+		Aggregation
+		Max() (number.Number, error)
+	}
+
+	// LastValue returns the latest value that was aggregated.
+	LastValue interface {
+		Aggregation
+		LastValue() (number.Number, time.Time, error)
+	}
+
+	// Points returns the raw values that were aggregated.
+	Points interface {
+		Aggregation
+
+		// Points returns points in the order they were
+		// recorded.  Points are approximately ordered by
+		// timestamp, but this is not guaranteed.
+		Points() ([]Point, error)
+	}
+
+	// Point is a raw data point, consisting of a number and value.
+	Point struct {
+		number.Number
+		time.Time
+	}
+
+	// Buckets represents histogram buckets boundaries and counts.
+	//
+	// For a Histogram with N defined boundaries, e.g, [x, y, z].
+	// There are N+1 counts: [-inf, x), [x, y), [y, z), [z, +inf]
+	Buckets struct {
+		// Boundaries are floating point numbers, even when
+		// aggregating integers.
+		Boundaries []float64
+
+		// Counts holds the count in each bucket.
+		Counts []uint64
+	}
+
+	// Histogram returns the count of events in pre-determined buckets.
+	Histogram interface {
+		Aggregation
+		Count() (uint64, error)
+		Sum() (number.Number, error)
+		Histogram() (Buckets, error)
+	}
+
+	// MinMaxSumCount supports the Min, Max, Sum, and Count interfaces.
+	MinMaxSumCount interface {
+		Aggregation
+		Min() (number.Number, error)
+		Max() (number.Number, error)
+		Sum() (number.Number, error)
+		Count() (uint64, error)
+	}
+)
+
+type (
+	// Kind is a short name for the Aggregator that produces an
+	// Aggregation, used for descriptive purpose only.  Kind is a
+	// string to allow user-defined Aggregators.
+	//
+	// When deciding how to handle an Aggregation, Exporters are
+	// encouraged to decide based on conversion to the above
+	// interfaces based on strength, not on Kind value, when
+	// deciding how to expose metric data.  This enables
+	// user-supplied Aggregators to replace builtin Aggregators.
+	//
+	// For example, test for a Distribution before testing for a
+	// MinMaxSumCount, test for a Histogram before testing for a
+	// Sum, and so on.
+	Kind string
+)
+
+const (
+	SumKind            Kind = "Sum"
+	MinMaxSumCountKind Kind = "MinMaxSumCount"
+	HistogramKind      Kind = "Histogram"
+	LastValueKind      Kind = "Lastvalue"
+	ExactKind          Kind = "Exact"
+)
+
+var (
+	ErrNegativeInput    = fmt.Errorf("negative value is out of range for this instrument")
+	ErrNaNInput         = fmt.Errorf("NaN value is an invalid input")
+	ErrInconsistentType = fmt.Errorf("inconsistent aggregator types")
+	ErrNoSubtraction    = fmt.Errorf("aggregator does not subtract")
+
+	// ErrNoData is returned when (due to a race with collection)
+	// the Aggregator is check-pointed before the first value is set.
+	// The aggregator should simply be skipped in this case.
+	ErrNoData = fmt.Errorf("no data collected by this aggregator")
+)
+
+// String returns the string value of Kind.
+func (k Kind) String() string {
+	return string(k)
+}

vendor/go.opentelemetry.io/otel/sdk/export/metric/exportkind_string.go

@@ -0,0 +1,25 @@
+// Code generated by "stringer -type=ExportKind"; DO NOT EDIT.
+
+package metric
+
+import "strconv"
+
+func _() {
+	// An "invalid array index" compiler error signifies that the constant values have changed.
+	// Re-run the stringer command to generate them again.
+	var x [1]struct{}
+	_ = x[CumulativeExportKind-1]
+	_ = x[DeltaExportKind-2]
+}
+
+const _ExportKind_name = "CumulativeExportKindDeltaExportKind"
+
+var _ExportKind_index = [...]uint8{0, 20, 35}
+
+func (i ExportKind) String() string {
+	i -= 1
+	if i < 0 || i >= ExportKind(len(_ExportKind_index)-1) {
+		return "ExportKind(" + strconv.FormatInt(int64(i+1), 10) + ")"
+	}
+	return _ExportKind_name[_ExportKind_index[i]:_ExportKind_index[i+1]]
+}

vendor/go.opentelemetry.io/otel/sdk/export/metric/go.mod

@@ -0,0 +1,54 @@
+module go.opentelemetry.io/otel/sdk/export/metric
+
+go 1.14
+
+replace go.opentelemetry.io/otel => ../../..
+
+replace go.opentelemetry.io/otel/bridge/opencensus => ../../../bridge/opencensus
+
+replace go.opentelemetry.io/otel/bridge/opentracing => ../../../bridge/opentracing
+
+replace go.opentelemetry.io/otel/example/jaeger => ../../../example/jaeger
+
+replace go.opentelemetry.io/otel/example/namedtracer => ../../../example/namedtracer
+
+replace go.opentelemetry.io/otel/example/opencensus => ../../../example/opencensus
+
+replace go.opentelemetry.io/otel/example/otel-collector => ../../../example/otel-collector
+
+replace go.opentelemetry.io/otel/example/prom-collector => ../../../example/prom-collector
+
+replace go.opentelemetry.io/otel/example/prometheus => ../../../example/prometheus
+
+replace go.opentelemetry.io/otel/example/zipkin => ../../../example/zipkin
+
+replace go.opentelemetry.io/otel/exporters/metric/prometheus => ../../../exporters/metric/prometheus
+
+replace go.opentelemetry.io/otel/exporters/otlp => ../../../exporters/otlp
+
+replace go.opentelemetry.io/otel/exporters/stdout => ../../../exporters/stdout
+
+replace go.opentelemetry.io/otel/exporters/trace/jaeger => ../../../exporters/trace/jaeger
+
+replace go.opentelemetry.io/otel/exporters/trace/zipkin => ../../../exporters/trace/zipkin
+
+replace go.opentelemetry.io/otel/internal/tools => ../../../internal/tools
+
+replace go.opentelemetry.io/otel/metric => ../../../metric
+
+replace go.opentelemetry.io/otel/oteltest => ../../../oteltest
+
+replace go.opentelemetry.io/otel/sdk => ../..
+
+replace go.opentelemetry.io/otel/sdk/export/metric => ./
+
+replace go.opentelemetry.io/otel/sdk/metric => ../../metric
+
+replace go.opentelemetry.io/otel/trace => ../../../trace
+
+require (
+	github.com/stretchr/testify v1.7.0
+	go.opentelemetry.io/otel v0.20.0
+	go.opentelemetry.io/otel/metric v0.20.0
+	go.opentelemetry.io/otel/sdk v0.20.0
+)

vendor/go.opentelemetry.io/otel/sdk/export/metric/go.sum

@@ -0,0 +1,15 @@
+github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8=
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/google/go-cmp v0.5.5 h1:Khx7svrCpmxxtHBq5j2mp/xVjsi8hQMfNLvJFAlrGgU=
+github.com/google/go-cmp v0.5.5/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/testify v1.7.0 h1:nwc3DEeHmmLAfoZucVR881uASk0Mfjw8xYJ99tb5CcY=
+github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
+golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543 h1:E7g+9GITq07hpfrRu66IVDexMakfv52eLZ2CXBWiKr4=
+golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c h1:dUUwHk2QECo/6vqA44rthZ8ie2QXMNeKRTHCNY2nXvo=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

vendor/go.opentelemetry.io/otel/sdk/export/metric/metric.go

@@ -0,0 +1,445 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//go:generate stringer -type=ExportKind
+
+package metric // import "go.opentelemetry.io/otel/sdk/export/metric"
+
+import (
+	"context"
+	"sync"
+	"time"
+
+	"go.opentelemetry.io/otel/attribute"
+	"go.opentelemetry.io/otel/metric"
+	"go.opentelemetry.io/otel/metric/number"
+	"go.opentelemetry.io/otel/sdk/export/metric/aggregation"
+	"go.opentelemetry.io/otel/sdk/resource"
+)
+
+// Processor is responsible for deciding which kind of aggregation to
+// use (via AggregatorSelector), gathering exported results from the
+// SDK during collection, and deciding over which dimensions to group
+// the exported data.
+//
+// The SDK supports binding only one of these interfaces, as it has
+// the sole responsibility of determining which Aggregator to use for
+// each record.
+//
+// The embedded AggregatorSelector interface is called (concurrently)
+// in instrumentation context to select the appropriate Aggregator for
+// an instrument.
+//
+// The `Process` method is called during collection in a
+// single-threaded context from the SDK, after the aggregator is
+// checkpointed, allowing the processor to build the set of metrics
+// currently being exported.
+type Processor interface {
+	// AggregatorSelector is responsible for selecting the
+	// concrete type of Aggregator used for a metric in the SDK.
+	//
+	// This may be a static decision based on fields of the
+	// Descriptor, or it could use an external configuration
+	// source to customize the treatment of each metric
+	// instrument.
+	//
+	// The result from AggregatorSelector.AggregatorFor should be
+	// the same type for a given Descriptor or else nil.  The same
+	// type should be returned for a given descriptor, because
+	// Aggregators only know how to Merge with their own type.  If
+	// the result is nil, the metric instrument will be disabled.
+	//
+	// Note that the SDK only calls AggregatorFor when new records
+	// require an Aggregator. This does not provide a way to
+	// disable metrics with active records.
+	AggregatorSelector
+
+	// Process is called by the SDK once per internal record,
+	// passing the export Accumulation (a Descriptor, the corresponding
+	// Labels, and the checkpointed Aggregator).  This call has no
+	// Context argument because it is expected to perform only
+	// computation.  An SDK is not expected to call exporters from
+	// with Process, use a controller for that (see
+	// ./controllers/{pull,push}.
+	Process(accum Accumulation) error
+}
+
+// AggregatorSelector supports selecting the kind of Aggregator to
+// use at runtime for a specific metric instrument.
+type AggregatorSelector interface {
+	// AggregatorFor allocates a variable number of aggregators of
+	// a kind suitable for the requested export.  This method
+	// initializes a `...*Aggregator`, to support making a single
+	// allocation.
+	//
+	// When the call returns without initializing the *Aggregator
+	// to a non-nil value, the metric instrument is explicitly
+	// disabled.
+	//
+	// This must return a consistent type to avoid confusion in
+	// later stages of the metrics export process, i.e., when
+	// Merging or Checkpointing aggregators for a specific
+	// instrument.
+	//
+	// Note: This is context-free because the aggregator should
+	// not relate to the incoming context.  This call should not
+	// block.
+	AggregatorFor(descriptor *metric.Descriptor, aggregator ...*Aggregator)
+}
+
+// Checkpointer is the interface used by a Controller to coordinate
+// the Processor with Accumulator(s) and Exporter(s).  The
+// StartCollection() and FinishCollection() methods start and finish a
+// collection interval.  Controllers call the Accumulator(s) during
+// collection to process Accumulations.
+type Checkpointer interface {
+	// Processor processes metric data for export.  The Process
+	// method is bracketed by StartCollection and FinishCollection
+	// calls.  The embedded AggregatorSelector can be called at
+	// any time.
+	Processor
+
+	// CheckpointSet returns the current data set.  This may be
+	// called before and after collection.  The
+	// implementation is required to return the same value
+	// throughout its lifetime, since CheckpointSet exposes a
+	// sync.Locker interface.  The caller is responsible for
+	// locking the CheckpointSet before initiating collection.
+	CheckpointSet() CheckpointSet
+
+	// StartCollection begins a collection interval.
+	StartCollection()
+
+	// FinishCollection ends a collection interval.
+	FinishCollection() error
+}
+
+// Aggregator implements a specific aggregation behavior, e.g., a
+// behavior to track a sequence of updates to an instrument.  Sum-only
+// instruments commonly use a simple Sum aggregator, but for the
+// distribution instruments (ValueRecorder, ValueObserver) there are a
+// number of possible aggregators with different cost and accuracy
+// tradeoffs.
+//
+// Note that any Aggregator may be attached to any instrument--this is
+// the result of the OpenTelemetry API/SDK separation.  It is possible
+// to attach a Sum aggregator to a ValueRecorder instrument or a
+// MinMaxSumCount aggregator to a Counter instrument.
+type Aggregator interface {
+	// Aggregation returns an Aggregation interface to access the
+	// current state of this Aggregator.  The caller is
+	// responsible for synchronization and must not call any the
+	// other methods in this interface concurrently while using
+	// the Aggregation.
+	Aggregation() aggregation.Aggregation
+
+	// Update receives a new measured value and incorporates it
+	// into the aggregation.  Update() calls may be called
+	// concurrently.
+	//
+	// Descriptor.NumberKind() should be consulted to determine
+	// whether the provided number is an int64 or float64.
+	//
+	// The Context argument comes from user-level code and could be
+	// inspected for a `correlation.Map` or `trace.SpanContext`.
+	Update(ctx context.Context, number number.Number, descriptor *metric.Descriptor) error
+
+	// SynchronizedMove is called during collection to finish one
+	// period of aggregation by atomically saving the
+	// currently-updating state into the argument Aggregator AND
+	// resetting the current value to the zero state.
+	//
+	// SynchronizedMove() is called concurrently with Update().  These
+	// two methods must be synchronized with respect to each
+	// other, for correctness.
+	//
+	// After saving a synchronized copy, the Aggregator can be converted
+	// into one or more of the interfaces in the `aggregation` sub-package,
+	// according to kind of Aggregator that was selected.
+	//
+	// This method will return an InconsistentAggregatorError if
+	// this Aggregator cannot be copied into the destination due
+	// to an incompatible type.
+	//
+	// This call has no Context argument because it is expected to
+	// perform only computation.
+	//
+	// When called with a nil `destination`, this Aggregator is reset
+	// and the current value is discarded.
+	SynchronizedMove(destination Aggregator, descriptor *metric.Descriptor) error
+
+	// Merge combines the checkpointed state from the argument
+	// Aggregator into this Aggregator.  Merge is not synchronized
+	// with respect to Update or SynchronizedMove.
+	//
+	// The owner of an Aggregator being merged is responsible for
+	// synchronization of both Aggregator states.
+	Merge(aggregator Aggregator, descriptor *metric.Descriptor) error
+}
+
+// Subtractor is an optional interface implemented by some
+// Aggregators.  An Aggregator must support `Subtract()` in order to
+// be configured for a Precomputed-Sum instrument (SumObserver,
+// UpDownSumObserver) using a DeltaExporter.
+type Subtractor interface {
+	// Subtract subtracts the `operand` from this Aggregator and
+	// outputs the value in `result`.
+	Subtract(operand, result Aggregator, descriptor *metric.Descriptor) error
+}
+
+// Exporter handles presentation of the checkpoint of aggregate
+// metrics.  This is the final stage of a metrics export pipeline,
+// where metric data are formatted for a specific system.
+type Exporter interface {
+	// Export is called immediately after completing a collection
+	// pass in the SDK.
+	//
+	// The Context comes from the controller that initiated
+	// collection.
+	//
+	// The CheckpointSet interface refers to the Processor that just
+	// completed collection.
+	Export(ctx context.Context, checkpointSet CheckpointSet) error
+
+	// ExportKindSelector is an interface used by the Processor
+	// in deciding whether to compute Delta or Cumulative
+	// Aggregations when passing Records to this Exporter.
+	ExportKindSelector
+}
+
+// ExportKindSelector is a sub-interface of Exporter used to indicate
+// whether the Processor should compute Delta or Cumulative
+// Aggregations.
+type ExportKindSelector interface {
+	// ExportKindFor should return the correct ExportKind that
+	// should be used when exporting data for the given metric
+	// instrument and Aggregator kind.
+	ExportKindFor(descriptor *metric.Descriptor, aggregatorKind aggregation.Kind) ExportKind
+}
+
+// CheckpointSet allows a controller to access a complete checkpoint of
+// aggregated metrics from the Processor.  This is passed to the
+// Exporter which may then use ForEach to iterate over the collection
+// of aggregated metrics.
+type CheckpointSet interface {
+	// ForEach iterates over aggregated checkpoints for all
+	// metrics that were updated during the last collection
+	// period. Each aggregated checkpoint returned by the
+	// function parameter may return an error.
+	//
+	// The ExportKindSelector argument is used to determine
+	// whether the Record is computed using Delta or Cumulative
+	// aggregation.
+	//
+	// ForEach tolerates ErrNoData silently, as this is
+	// expected from the Meter implementation. Any other kind
+	// of error will immediately halt ForEach and return
+	// the error to the caller.
+	ForEach(kindSelector ExportKindSelector, recordFunc func(Record) error) error
+
+	// Locker supports locking the checkpoint set.  Collection
+	// into the checkpoint set cannot take place (in case of a
+	// stateful processor) while it is locked.
+	//
+	// The Processor attached to the Accumulator MUST be called
+	// with the lock held.
+	sync.Locker
+
+	// RLock acquires a read lock corresponding to this Locker.
+	RLock()
+	// RUnlock releases a read lock corresponding to this Locker.
+	RUnlock()
+}
+
+// Metadata contains the common elements for exported metric data that
+// are shared by the Accumulator->Processor and Processor->Exporter
+// steps.
+type Metadata struct {
+	descriptor *metric.Descriptor
+	labels     *attribute.Set
+	resource   *resource.Resource
+}
+
+// Accumulation contains the exported data for a single metric instrument
+// and label set, as prepared by an Accumulator for the Processor.
+type Accumulation struct {
+	Metadata
+	aggregator Aggregator
+}
+
+// Record contains the exported data for a single metric instrument
+// and label set, as prepared by the Processor for the Exporter.
+// This includes the effective start and end time for the aggregation.
+type Record struct {
+	Metadata
+	aggregation aggregation.Aggregation
+	start       time.Time
+	end         time.Time
+}
+
+// Descriptor describes the metric instrument being exported.
+func (m Metadata) Descriptor() *metric.Descriptor {
+	return m.descriptor
+}
+
+// Labels describes the labels associated with the instrument and the
+// aggregated data.
+func (m Metadata) Labels() *attribute.Set {
+	return m.labels
+}
+
+// Resource contains common attributes that apply to this metric event.
+func (m Metadata) Resource() *resource.Resource {
+	return m.resource
+}
+
+// NewAccumulation allows Accumulator implementations to construct new
+// Accumulations to send to Processors. The Descriptor, Labels, Resource,
+// and Aggregator represent aggregate metric events received over a single
+// collection period.
+func NewAccumulation(descriptor *metric.Descriptor, labels *attribute.Set, resource *resource.Resource, aggregator Aggregator) Accumulation {
+	return Accumulation{
+		Metadata: Metadata{
+			descriptor: descriptor,
+			labels:     labels,
+			resource:   resource,
+		},
+		aggregator: aggregator,
+	}
+}
+
+// Aggregator returns the checkpointed aggregator. It is safe to
+// access the checkpointed state without locking.
+func (r Accumulation) Aggregator() Aggregator {
+	return r.aggregator
+}
+
+// NewRecord allows Processor implementations to construct export
+// records.  The Descriptor, Labels, and Aggregator represent
+// aggregate metric events received over a single collection period.
+func NewRecord(descriptor *metric.Descriptor, labels *attribute.Set, resource *resource.Resource, aggregation aggregation.Aggregation, start, end time.Time) Record {
+	return Record{
+		Metadata: Metadata{
+			descriptor: descriptor,
+			labels:     labels,
+			resource:   resource,
+		},
+		aggregation: aggregation,
+		start:       start,
+		end:         end,
+	}
+}
+
+// Aggregation returns the aggregation, an interface to the record and
+// its aggregator, dependent on the kind of both the input and exporter.
+func (r Record) Aggregation() aggregation.Aggregation {
+	return r.aggregation
+}
+
+// StartTime is the start time of the interval covered by this aggregation.
+func (r Record) StartTime() time.Time {
+	return r.start
+}
+
+// EndTime is the end time of the interval covered by this aggregation.
+func (r Record) EndTime() time.Time {
+	return r.end
+}
+
+// ExportKind indicates the kind of data exported by an exporter.
+// These bits may be OR-d together when multiple exporters are in use.
+type ExportKind int
+
+const (
+	// CumulativeExportKind indicates that an Exporter expects a
+	// Cumulative Aggregation.
+	CumulativeExportKind ExportKind = 1
+
+	// DeltaExportKind indicates that an Exporter expects a
+	// Delta Aggregation.
+	DeltaExportKind ExportKind = 2
+)
+
+// Includes tests whether `kind` includes a specific kind of
+// exporter.
+func (kind ExportKind) Includes(has ExportKind) bool {
+	return kind&has != 0
+}
+
+// MemoryRequired returns whether an exporter of this kind requires
+// memory to export correctly.
+func (kind ExportKind) MemoryRequired(mkind metric.InstrumentKind) bool {
+	switch mkind {
+	case metric.ValueRecorderInstrumentKind, metric.ValueObserverInstrumentKind,
+		metric.CounterInstrumentKind, metric.UpDownCounterInstrumentKind:
+		// Delta-oriented instruments:
+		return kind.Includes(CumulativeExportKind)
+
+	case metric.SumObserverInstrumentKind, metric.UpDownSumObserverInstrumentKind:
+		// Cumulative-oriented instruments:
+		return kind.Includes(DeltaExportKind)
+	}
+	// Something unexpected is happening--we could panic.  This
+	// will become an error when the exporter tries to access a
+	// checkpoint, presumably, so let it be.
+	return false
+}
+
+type (
+	constantExportKindSelector  ExportKind
+	statelessExportKindSelector struct{}
+)
+
+var (
+	_ ExportKindSelector = constantExportKindSelector(0)
+	_ ExportKindSelector = statelessExportKindSelector{}
+)
+
+// ConstantExportKindSelector returns an ExportKindSelector that returns
+// a constant ExportKind, one that is either always cumulative or always delta.
+func ConstantExportKindSelector(kind ExportKind) ExportKindSelector {
+	return constantExportKindSelector(kind)
+}
+
+// CumulativeExportKindSelector returns an ExportKindSelector that
+// always returns CumulativeExportKind.
+func CumulativeExportKindSelector() ExportKindSelector {
+	return ConstantExportKindSelector(CumulativeExportKind)
+}
+
+// DeltaExportKindSelector returns an ExportKindSelector that
+// always returns DeltaExportKind.
+func DeltaExportKindSelector() ExportKindSelector {
+	return ConstantExportKindSelector(DeltaExportKind)
+}
+
+// StatelessExportKindSelector returns an ExportKindSelector that
+// always returns the ExportKind that avoids long-term memory
+// requirements.
+func StatelessExportKindSelector() ExportKindSelector {
+	return statelessExportKindSelector{}
+}
+
+// ExportKindFor implements ExportKindSelector.
+func (c constantExportKindSelector) ExportKindFor(_ *metric.Descriptor, _ aggregation.Kind) ExportKind {
+	return ExportKind(c)
+}
+
+// ExportKindFor implements ExportKindSelector.
+func (s statelessExportKindSelector) ExportKindFor(desc *metric.Descriptor, kind aggregation.Kind) ExportKind {
+	if kind == aggregation.SumKind && desc.InstrumentKind().PrecomputedSum() {
+		return CumulativeExportKind
+	}
+	return DeltaExportKind
+}

vendor/go.opentelemetry.io/otel/sdk/instrumentation/library.go

@@ -0,0 +1,35 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+/*
+Package instrumentation provides an instrumentation library structure to be
+passed to both the OpenTelemetry Tracer and Meter components.
+
+This package is currently in a pre-GA phase. Backwards incompatible changes
+may be introduced in subsequent minor version releases as we work to track the
+evolving OpenTelemetry specification and user feedback.
+
+For more information see
+[this](https://github.com/open-telemetry/oteps/blob/main/text/0083-component.md).
+*/
+package instrumentation // import "go.opentelemetry.io/otel/sdk/instrumentation"
+
+// Library represents the instrumentation library.
+type Library struct {
+	// Name is the name of the instrumentation library. This should be the
+	// Go package name of that library.
+	Name string
+	// Version is the version of the instrumentation library.
+	Version string
+}

vendor/go.opentelemetry.io/otel/sdk/internal/internal.go

@@ -0,0 +1,37 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package internal // import "go.opentelemetry.io/otel/sdk/internal"
+
+import (
+	"fmt"
+	"time"
+
+	"go.opentelemetry.io/otel"
+)
+
+// UserAgent is the user agent to be added to the outgoing
+// requests from the exporters.
+var UserAgent = fmt.Sprintf("opentelemetry-go/%s", otel.Version())
+
+// MonotonicEndTime returns the end time at present
+// but offset from start, monotonically.
+//
+// The monotonic clock is used in subtractions hence
+// the duration since start added back to start gives
+// end as a monotonic time.
+// See https://golang.org/pkg/time/#hdr-Monotonic_Clocks
+func MonotonicEndTime(start time.Time) time.Time {
+	return start.Add(time.Since(start))
+}

vendor/go.opentelemetry.io/otel/sdk/internal/sanitize.go

@@ -0,0 +1,50 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package internal
+
+import (
+	"strings"
+	"unicode"
+)
+
+const labelKeySizeLimit = 100
+
+// Sanitize returns a string that is trunacated to 100 characters if it's too
+// long, and replaces non-alphanumeric characters to underscores.
+func Sanitize(s string) string {
+	if len(s) == 0 {
+		return s
+	}
+	if len(s) > labelKeySizeLimit {
+		s = s[:labelKeySizeLimit]
+	}
+	s = strings.Map(sanitizeRune, s)
+	if unicode.IsDigit(rune(s[0])) {
+		s = "key_" + s
+	}
+	if s[0] == '_' {
+		s = "key" + s
+	}
+	return s
+}
+
+// converts anything that is not a letter or digit to an underscore
+func sanitizeRune(r rune) rune {
+	if unicode.IsLetter(r) || unicode.IsDigit(r) {
+		return r
+	}
+	// Everything else turns into an underscore
+	return '_'
+}

vendor/go.opentelemetry.io/otel/sdk/metric/LICENSE

@@ -0,0 +1,201 @@
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
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+      including but not limited to software source code, documentation
+      source, and configuration files.
+
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+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
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+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
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+      designated in writing by the copyright owner as "Not a Contribution."
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+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
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+      (d) If the Work includes a "NOTICE" text file as part of its
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+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
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+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
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+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.

vendor/go.opentelemetry.io/otel/sdk/metric/aggregator/aggregator.go

@@ -0,0 +1,52 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package aggregator // import "go.opentelemetry.io/otel/sdk/metric/aggregator"
+
+import (
+	"fmt"
+	"math"
+
+	"go.opentelemetry.io/otel/metric"
+	"go.opentelemetry.io/otel/metric/number"
+	export "go.opentelemetry.io/otel/sdk/export/metric"
+	"go.opentelemetry.io/otel/sdk/export/metric/aggregation"
+)
+
+// NewInconsistentAggregatorError formats an error describing an attempt to
+// Checkpoint or Merge different-type aggregators.  The result can be unwrapped as
+// an ErrInconsistentType.
+func NewInconsistentAggregatorError(a1, a2 export.Aggregator) error {
+	return fmt.Errorf("%w: %T and %T", aggregation.ErrInconsistentType, a1, a2)
+}
+
+// RangeTest is a common routine for testing for valid input values.
+// This rejects NaN values.  This rejects negative values when the
+// metric instrument does not support negative values, including
+// monotonic counter metrics and absolute ValueRecorder metrics.
+func RangeTest(num number.Number, descriptor *metric.Descriptor) error {
+	numberKind := descriptor.NumberKind()
+
+	if numberKind == number.Float64Kind && math.IsNaN(num.AsFloat64()) {
+		return aggregation.ErrNaNInput
+	}
+
+	switch descriptor.InstrumentKind() {
+	case metric.CounterInstrumentKind, metric.SumObserverInstrumentKind:
+		if num.IsNegative(numberKind) {
+			return aggregation.ErrNegativeInput
+		}
+	}
+	return nil
+}

vendor/go.opentelemetry.io/otel/sdk/metric/aggregator/exact/exact.go

@@ -0,0 +1,130 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package exact // import "go.opentelemetry.io/otel/sdk/metric/aggregator/exact"
+
+import (
+	"context"
+	"sync"
+	"time"
+
+	"go.opentelemetry.io/otel/metric"
+	"go.opentelemetry.io/otel/metric/number"
+	export "go.opentelemetry.io/otel/sdk/export/metric"
+	"go.opentelemetry.io/otel/sdk/export/metric/aggregation"
+	"go.opentelemetry.io/otel/sdk/metric/aggregator"
+)
+
+type (
+	// Aggregator aggregates events that form a distribution, keeping
+	// an array with the exact set of values.
+	Aggregator struct {
+		lock    sync.Mutex
+		samples []aggregation.Point
+	}
+)
+
+var _ export.Aggregator = &Aggregator{}
+var _ aggregation.Points = &Aggregator{}
+var _ aggregation.Count = &Aggregator{}
+
+// New returns cnt many new exact aggregators, which aggregate recorded
+// measurements by storing them in an array.  This type uses a mutex
+// for Update() and SynchronizedMove() concurrency.
+func New(cnt int) []Aggregator {
+	return make([]Aggregator, cnt)
+}
+
+// Aggregation returns an interface for reading the state of this aggregator.
+func (c *Aggregator) Aggregation() aggregation.Aggregation {
+	return c
+}
+
+// Kind returns aggregation.ExactKind.
+func (c *Aggregator) Kind() aggregation.Kind {
+	return aggregation.ExactKind
+}
+
+// Count returns the number of values in the checkpoint.
+func (c *Aggregator) Count() (uint64, error) {
+	return uint64(len(c.samples)), nil
+}
+
+// Points returns access to the raw data set.
+func (c *Aggregator) Points() ([]aggregation.Point, error) {
+	return c.samples, nil
+}
+
+// SynchronizedMove saves the current state to oa and resets the current state to
+// the empty set, taking a lock to prevent concurrent Update() calls.
+func (c *Aggregator) SynchronizedMove(oa export.Aggregator, desc *metric.Descriptor) error {
+	o, _ := oa.(*Aggregator)
+
+	if oa != nil && o == nil {
+		return aggregator.NewInconsistentAggregatorError(c, oa)
+	}
+
+	c.lock.Lock()
+	defer c.lock.Unlock()
+
+	if o != nil {
+		o.samples = c.samples
+	}
+	c.samples = nil
+
+	return nil
+}
+
+// Update adds the recorded measurement to the current data set.
+// Update takes a lock to prevent concurrent Update() and SynchronizedMove()
+// calls.
+func (c *Aggregator) Update(_ context.Context, number number.Number, desc *metric.Descriptor) error {
+	now := time.Now()
+	c.lock.Lock()
+	defer c.lock.Unlock()
+	c.samples = append(c.samples, aggregation.Point{
+		Number: number,
+		Time:   now,
+	})
+
+	return nil
+}
+
+// Merge combines two data sets into one.
+func (c *Aggregator) Merge(oa export.Aggregator, desc *metric.Descriptor) error {
+	o, _ := oa.(*Aggregator)
+	if o == nil {
+		return aggregator.NewInconsistentAggregatorError(c, oa)
+	}
+
+	c.samples = combine(c.samples, o.samples)
+	return nil
+}
+
+func combine(a, b []aggregation.Point) []aggregation.Point {
+	result := make([]aggregation.Point, 0, len(a)+len(b))
+
+	for len(a) != 0 && len(b) != 0 {
+		if a[0].Time.Before(b[0].Time) {
+			result = append(result, a[0])
+			a = a[1:]
+		} else {
+			result = append(result, b[0])
+			b = b[1:]
+		}
+	}
+	result = append(result, a...)
+	result = append(result, b...)
+	return result
+}

vendor/go.opentelemetry.io/otel/sdk/metric/aggregator/histogram/histogram.go

@@ -0,0 +1,270 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package histogram // import "go.opentelemetry.io/otel/sdk/metric/aggregator/histogram"
+
+import (
+	"context"
+	"sort"
+	"sync"
+
+	"go.opentelemetry.io/otel/metric"
+	"go.opentelemetry.io/otel/metric/number"
+	export "go.opentelemetry.io/otel/sdk/export/metric"
+	"go.opentelemetry.io/otel/sdk/export/metric/aggregation"
+	"go.opentelemetry.io/otel/sdk/metric/aggregator"
+)
+
+// Note: This code uses a Mutex to govern access to the exclusive
+// aggregator state.  This is in contrast to a lock-free approach
+// (as in the Go prometheus client) that was reverted here:
+// https://github.com/open-telemetry/opentelemetry-go/pull/669
+
+type (
+	// Aggregator observe events and counts them in pre-determined buckets.
+	// It also calculates the sum and count of all events.
+	Aggregator struct {
+		lock       sync.Mutex
+		boundaries []float64
+		kind       number.Kind
+		state      *state
+	}
+
+	// config describes how the histogram is aggregated.
+	config struct {
+		// explicitBoundaries support arbitrary bucketing schemes.  This
+		// is the general case.
+		explicitBoundaries []float64
+	}
+
+	// Option configures a histogram config.
+	Option interface {
+		// apply sets one or more config fields.
+		apply(*config)
+	}
+
+	// state represents the state of a histogram, consisting of
+	// the sum and counts for all observed values and
+	// the less than equal bucket count for the pre-determined boundaries.
+	state struct {
+		bucketCounts []uint64
+		sum          number.Number
+		count        uint64
+	}
+)
+
+// WithExplicitBoundaries sets the ExplicitBoundaries configuration option of a config.
+func WithExplicitBoundaries(explicitBoundaries []float64) Option {
+	return explicitBoundariesOption{explicitBoundaries}
+}
+
+type explicitBoundariesOption struct {
+	boundaries []float64
+}
+
+func (o explicitBoundariesOption) apply(config *config) {
+	config.explicitBoundaries = o.boundaries
+}
+
+// defaultExplicitBoundaries have been copied from prometheus.DefBuckets.
+//
+// Note we anticipate the use of a high-precision histogram sketch as
+// the standard histogram aggregator for OTLP export.
+// (https://github.com/open-telemetry/opentelemetry-specification/issues/982).
+var defaultFloat64ExplicitBoundaries = []float64{.005, .01, .025, .05, .1, .25, .5, 1, 2.5, 5, 10}
+
+// defaultInt64ExplicitBoundaryMultiplier determines the default
+// integer histogram boundaries.
+const defaultInt64ExplicitBoundaryMultiplier = 1e6
+
+// defaultInt64ExplicitBoundaries applies a multiplier to the default
+// float64 boundaries: [ 5K, 10K, 25K, ..., 2.5M, 5M, 10M ]
+var defaultInt64ExplicitBoundaries = func(bounds []float64) (asint []float64) {
+	for _, f := range bounds {
+		asint = append(asint, defaultInt64ExplicitBoundaryMultiplier*f)
+	}
+	return
+}(defaultFloat64ExplicitBoundaries)
+
+var _ export.Aggregator = &Aggregator{}
+var _ aggregation.Sum = &Aggregator{}
+var _ aggregation.Count = &Aggregator{}
+var _ aggregation.Histogram = &Aggregator{}
+
+// New returns a new aggregator for computing Histograms.
+//
+// A Histogram observe events and counts them in pre-defined buckets.
+// And also provides the total sum and count of all observations.
+//
+// Note that this aggregator maintains each value using independent
+// atomic operations, which introduces the possibility that
+// checkpoints are inconsistent.
+func New(cnt int, desc *metric.Descriptor, opts ...Option) []Aggregator {
+	var cfg config
+
+	if desc.NumberKind() == number.Int64Kind {
+		cfg.explicitBoundaries = defaultInt64ExplicitBoundaries
+	} else {
+		cfg.explicitBoundaries = defaultFloat64ExplicitBoundaries
+	}
+
+	for _, opt := range opts {
+		opt.apply(&cfg)
+	}
+
+	aggs := make([]Aggregator, cnt)
+
+	// Boundaries MUST be ordered otherwise the histogram could not
+	// be properly computed.
+	sortedBoundaries := make([]float64, len(cfg.explicitBoundaries))
+
+	copy(sortedBoundaries, cfg.explicitBoundaries)
+	sort.Float64s(sortedBoundaries)
+
+	for i := range aggs {
+		aggs[i] = Aggregator{
+			kind:       desc.NumberKind(),
+			boundaries: sortedBoundaries,
+		}
+		aggs[i].state = aggs[i].newState()
+	}
+	return aggs
+}
+
+// Aggregation returns an interface for reading the state of this aggregator.
+func (c *Aggregator) Aggregation() aggregation.Aggregation {
+	return c
+}
+
+// Kind returns aggregation.HistogramKind.
+func (c *Aggregator) Kind() aggregation.Kind {
+	return aggregation.HistogramKind
+}
+
+// Sum returns the sum of all values in the checkpoint.
+func (c *Aggregator) Sum() (number.Number, error) {
+	return c.state.sum, nil
+}
+
+// Count returns the number of values in the checkpoint.
+func (c *Aggregator) Count() (uint64, error) {
+	return c.state.count, nil
+}
+
+// Histogram returns the count of events in pre-determined buckets.
+func (c *Aggregator) Histogram() (aggregation.Buckets, error) {
+	return aggregation.Buckets{
+		Boundaries: c.boundaries,
+		Counts:     c.state.bucketCounts,
+	}, nil
+}
+
+// SynchronizedMove saves the current state into oa and resets the current state to
+// the empty set.  Since no locks are taken, there is a chance that
+// the independent Sum, Count and Bucket Count are not consistent with each
+// other.
+func (c *Aggregator) SynchronizedMove(oa export.Aggregator, desc *metric.Descriptor) error {
+	o, _ := oa.(*Aggregator)
+
+	if oa != nil && o == nil {
+		return aggregator.NewInconsistentAggregatorError(c, oa)
+	}
+
+	if o != nil {
+		// Swap case: This is the ordinary case for a
+		// synchronous instrument, where the SDK allocates two
+		// Aggregators and lock contention is anticipated.
+		// Reset the target state before swapping it under the
+		// lock below.
+		o.clearState()
+	}
+
+	c.lock.Lock()
+	if o != nil {
+		c.state, o.state = o.state, c.state
+	} else {
+		// No swap case: This is the ordinary case for an
+		// asynchronous instrument, where the SDK allocates a
+		// single Aggregator and there is no anticipated lock
+		// contention.
+		c.clearState()
+	}
+	c.lock.Unlock()
+
+	return nil
+}
+
+func (c *Aggregator) newState() *state {
+	return &state{
+		bucketCounts: make([]uint64, len(c.boundaries)+1),
+	}
+}
+
+func (c *Aggregator) clearState() {
+	for i := range c.state.bucketCounts {
+		c.state.bucketCounts[i] = 0
+	}
+	c.state.sum = 0
+	c.state.count = 0
+}
+
+// Update adds the recorded measurement to the current data set.
+func (c *Aggregator) Update(_ context.Context, number number.Number, desc *metric.Descriptor) error {
+	kind := desc.NumberKind()
+	asFloat := number.CoerceToFloat64(kind)
+
+	bucketID := len(c.boundaries)
+	for i, boundary := range c.boundaries {
+		if asFloat < boundary {
+			bucketID = i
+			break
+		}
+	}
+	// Note: Binary-search was compared using the benchmarks. The following
+	// code is equivalent to the linear search above:
+	//
+	//     bucketID := sort.Search(len(c.boundaries), func(i int) bool {
+	//         return asFloat < c.boundaries[i]
+	//     })
+	//
+	// The binary search wins for very large boundary sets, but
+	// the linear search performs better up through arrays between
+	// 256 and 512 elements, which is a relatively large histogram, so we
+	// continue to prefer linear search.
+
+	c.lock.Lock()
+	defer c.lock.Unlock()
+
+	c.state.count++
+	c.state.sum.AddNumber(kind, number)
+	c.state.bucketCounts[bucketID]++
+
+	return nil
+}
+
+// Merge combines two histograms that have the same buckets into a single one.
+func (c *Aggregator) Merge(oa export.Aggregator, desc *metric.Descriptor) error {
+	o, _ := oa.(*Aggregator)
+	if o == nil {
+		return aggregator.NewInconsistentAggregatorError(c, oa)
+	}
+
+	c.state.sum.AddNumber(desc.NumberKind(), o.state.sum)
+	c.state.count += o.state.count
+
+	for i := 0; i < len(c.state.bucketCounts); i++ {
+		c.state.bucketCounts[i] += o.state.bucketCounts[i]
+	}
+	return nil
+}

vendor/go.opentelemetry.io/otel/sdk/metric/aggregator/lastvalue/lastvalue.go

@@ -0,0 +1,135 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package lastvalue // import "go.opentelemetry.io/otel/sdk/metric/aggregator/lastvalue"
+
+import (
+	"context"
+	"sync/atomic"
+	"time"
+	"unsafe"
+
+	"go.opentelemetry.io/otel/metric"
+	"go.opentelemetry.io/otel/metric/number"
+	export "go.opentelemetry.io/otel/sdk/export/metric"
+	"go.opentelemetry.io/otel/sdk/export/metric/aggregation"
+	"go.opentelemetry.io/otel/sdk/metric/aggregator"
+)
+
+type (
+
+	// Aggregator aggregates lastValue events.
+	Aggregator struct {
+		// value is an atomic pointer to *lastValueData.  It is never nil.
+		value unsafe.Pointer
+	}
+
+	// lastValueData stores the current value of a lastValue along with
+	// a sequence number to determine the winner of a race.
+	lastValueData struct {
+		// value is the int64- or float64-encoded Set() data
+		//
+		// value needs to be aligned for 64-bit atomic operations.
+		value number.Number
+
+		// timestamp indicates when this record was submitted.
+		// this can be used to pick a winner when multiple
+		// records contain lastValue data for the same labels due
+		// to races.
+		timestamp time.Time
+	}
+)
+
+var _ export.Aggregator = &Aggregator{}
+var _ aggregation.LastValue = &Aggregator{}
+
+// An unset lastValue has zero timestamp and zero value.
+var unsetLastValue = &lastValueData{}
+
+// New returns a new lastValue aggregator.  This aggregator retains the
+// last value and timestamp that were recorded.
+func New(cnt int) []Aggregator {
+	aggs := make([]Aggregator, cnt)
+	for i := range aggs {
+		aggs[i] = Aggregator{
+			value: unsafe.Pointer(unsetLastValue),
+		}
+	}
+	return aggs
+}
+
+// Aggregation returns an interface for reading the state of this aggregator.
+func (g *Aggregator) Aggregation() aggregation.Aggregation {
+	return g
+}
+
+// Kind returns aggregation.LastValueKind.
+func (g *Aggregator) Kind() aggregation.Kind {
+	return aggregation.LastValueKind
+}
+
+// LastValue returns the last-recorded lastValue value and the
+// corresponding timestamp.  The error value aggregation.ErrNoData
+// will be returned if (due to a race condition) the checkpoint was
+// computed before the first value was set.
+func (g *Aggregator) LastValue() (number.Number, time.Time, error) {
+	gd := (*lastValueData)(g.value)
+	if gd == unsetLastValue {
+		return 0, time.Time{}, aggregation.ErrNoData
+	}
+	return gd.value.AsNumber(), gd.timestamp, nil
+}
+
+// SynchronizedMove atomically saves the current value.
+func (g *Aggregator) SynchronizedMove(oa export.Aggregator, _ *metric.Descriptor) error {
+	if oa == nil {
+		atomic.StorePointer(&g.value, unsafe.Pointer(unsetLastValue))
+		return nil
+	}
+	o, _ := oa.(*Aggregator)
+	if o == nil {
+		return aggregator.NewInconsistentAggregatorError(g, oa)
+	}
+	o.value = atomic.SwapPointer(&g.value, unsafe.Pointer(unsetLastValue))
+	return nil
+}
+
+// Update atomically sets the current "last" value.
+func (g *Aggregator) Update(_ context.Context, number number.Number, desc *metric.Descriptor) error {
+	ngd := &lastValueData{
+		value:     number,
+		timestamp: time.Now(),
+	}
+	atomic.StorePointer(&g.value, unsafe.Pointer(ngd))
+	return nil
+}
+
+// Merge combines state from two aggregators.  The most-recently set
+// value is chosen.
+func (g *Aggregator) Merge(oa export.Aggregator, desc *metric.Descriptor) error {
+	o, _ := oa.(*Aggregator)
+	if o == nil {
+		return aggregator.NewInconsistentAggregatorError(g, oa)
+	}
+
+	ggd := (*lastValueData)(atomic.LoadPointer(&g.value))
+	ogd := (*lastValueData)(atomic.LoadPointer(&o.value))
+
+	if ggd.timestamp.After(ogd.timestamp) {
+		return nil
+	}
+
+	g.value = unsafe.Pointer(ogd)
+	return nil
+}

vendor/go.opentelemetry.io/otel/sdk/metric/aggregator/minmaxsumcount/mmsc.go

@@ -0,0 +1,165 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package minmaxsumcount // import "go.opentelemetry.io/otel/sdk/metric/aggregator/minmaxsumcount"
+
+import (
+	"context"
+	"sync"
+
+	"go.opentelemetry.io/otel/metric"
+	"go.opentelemetry.io/otel/metric/number"
+	export "go.opentelemetry.io/otel/sdk/export/metric"
+	"go.opentelemetry.io/otel/sdk/export/metric/aggregation"
+	"go.opentelemetry.io/otel/sdk/metric/aggregator"
+)
+
+type (
+	// Aggregator aggregates events that form a distribution,
+	// keeping only the min, max, sum, and count.
+	Aggregator struct {
+		lock sync.Mutex
+		kind number.Kind
+		state
+	}
+
+	state struct {
+		sum   number.Number
+		min   number.Number
+		max   number.Number
+		count uint64
+	}
+)
+
+var _ export.Aggregator = &Aggregator{}
+var _ aggregation.MinMaxSumCount = &Aggregator{}
+
+// New returns a new aggregator for computing the min, max, sum, and
+// count.
+//
+// This type uses a mutex for Update() and SynchronizedMove() concurrency.
+func New(cnt int, desc *metric.Descriptor) []Aggregator {
+	kind := desc.NumberKind()
+	aggs := make([]Aggregator, cnt)
+	for i := range aggs {
+		aggs[i] = Aggregator{
+			kind:  kind,
+			state: emptyState(kind),
+		}
+	}
+	return aggs
+}
+
+// Aggregation returns an interface for reading the state of this aggregator.
+func (c *Aggregator) Aggregation() aggregation.Aggregation {
+	return c
+}
+
+// Kind returns aggregation.MinMaxSumCountKind.
+func (c *Aggregator) Kind() aggregation.Kind {
+	return aggregation.MinMaxSumCountKind
+}
+
+// Sum returns the sum of values in the checkpoint.
+func (c *Aggregator) Sum() (number.Number, error) {
+	return c.sum, nil
+}
+
+// Count returns the number of values in the checkpoint.
+func (c *Aggregator) Count() (uint64, error) {
+	return c.count, nil
+}
+
+// Min returns the minimum value in the checkpoint.
+// The error value aggregation.ErrNoData will be returned
+// if there were no measurements recorded during the checkpoint.
+func (c *Aggregator) Min() (number.Number, error) {
+	if c.count == 0 {
+		return 0, aggregation.ErrNoData
+	}
+	return c.min, nil
+}
+
+// Max returns the maximum value in the checkpoint.
+// The error value aggregation.ErrNoData will be returned
+// if there were no measurements recorded during the checkpoint.
+func (c *Aggregator) Max() (number.Number, error) {
+	if c.count == 0 {
+		return 0, aggregation.ErrNoData
+	}
+	return c.max, nil
+}
+
+// SynchronizedMove saves the current state into oa and resets the current state to
+// the empty set.
+func (c *Aggregator) SynchronizedMove(oa export.Aggregator, desc *metric.Descriptor) error {
+	o, _ := oa.(*Aggregator)
+
+	if oa != nil && o == nil {
+		return aggregator.NewInconsistentAggregatorError(c, oa)
+	}
+	c.lock.Lock()
+	if o != nil {
+		o.state = c.state
+	}
+	c.state = emptyState(c.kind)
+	c.lock.Unlock()
+
+	return nil
+}
+
+func emptyState(kind number.Kind) state {
+	return state{
+		count: 0,
+		sum:   0,
+		min:   kind.Maximum(),
+		max:   kind.Minimum(),
+	}
+}
+
+// Update adds the recorded measurement to the current data set.
+func (c *Aggregator) Update(_ context.Context, number number.Number, desc *metric.Descriptor) error {
+	kind := desc.NumberKind()
+
+	c.lock.Lock()
+	defer c.lock.Unlock()
+	c.count++
+	c.sum.AddNumber(kind, number)
+	if number.CompareNumber(kind, c.min) < 0 {
+		c.min = number
+	}
+	if number.CompareNumber(kind, c.max) > 0 {
+		c.max = number
+	}
+	return nil
+}
+
+// Merge combines two data sets into one.
+func (c *Aggregator) Merge(oa export.Aggregator, desc *metric.Descriptor) error {
+	o, _ := oa.(*Aggregator)
+	if o == nil {
+		return aggregator.NewInconsistentAggregatorError(c, oa)
+	}
+
+	c.count += o.count
+	c.sum.AddNumber(desc.NumberKind(), o.sum)
+
+	if c.min.CompareNumber(desc.NumberKind(), o.min) > 0 {
+		c.min.SetNumber(o.min)
+	}
+	if c.max.CompareNumber(desc.NumberKind(), o.max) < 0 {
+		c.max.SetNumber(o.max)
+	}
+	return nil
+}

vendor/go.opentelemetry.io/otel/sdk/metric/aggregator/sum/sum.go

@@ -0,0 +1,106 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package sum // import "go.opentelemetry.io/otel/sdk/metric/aggregator/sum"
+
+import (
+	"context"
+
+	"go.opentelemetry.io/otel/metric"
+	"go.opentelemetry.io/otel/metric/number"
+	export "go.opentelemetry.io/otel/sdk/export/metric"
+	"go.opentelemetry.io/otel/sdk/export/metric/aggregation"
+	"go.opentelemetry.io/otel/sdk/metric/aggregator"
+)
+
+// Aggregator aggregates counter events.
+type Aggregator struct {
+	// current holds current increments to this counter record
+	// current needs to be aligned for 64-bit atomic operations.
+	value number.Number
+}
+
+var _ export.Aggregator = &Aggregator{}
+var _ export.Subtractor = &Aggregator{}
+var _ aggregation.Sum = &Aggregator{}
+
+// New returns a new counter aggregator implemented by atomic
+// operations.  This aggregator implements the aggregation.Sum
+// export interface.
+func New(cnt int) []Aggregator {
+	return make([]Aggregator, cnt)
+}
+
+// Aggregation returns an interface for reading the state of this aggregator.
+func (c *Aggregator) Aggregation() aggregation.Aggregation {
+	return c
+}
+
+// Kind returns aggregation.SumKind.
+func (c *Aggregator) Kind() aggregation.Kind {
+	return aggregation.SumKind
+}
+
+// Sum returns the last-checkpointed sum.  This will never return an
+// error.
+func (c *Aggregator) Sum() (number.Number, error) {
+	return c.value, nil
+}
+
+// SynchronizedMove atomically saves the current value into oa and resets the
+// current sum to zero.
+func (c *Aggregator) SynchronizedMove(oa export.Aggregator, _ *metric.Descriptor) error {
+	if oa == nil {
+		c.value.SetRawAtomic(0)
+		return nil
+	}
+	o, _ := oa.(*Aggregator)
+	if o == nil {
+		return aggregator.NewInconsistentAggregatorError(c, oa)
+	}
+	o.value = c.value.SwapNumberAtomic(number.Number(0))
+	return nil
+}
+
+// Update atomically adds to the current value.
+func (c *Aggregator) Update(_ context.Context, num number.Number, desc *metric.Descriptor) error {
+	c.value.AddNumberAtomic(desc.NumberKind(), num)
+	return nil
+}
+
+// Merge combines two counters by adding their sums.
+func (c *Aggregator) Merge(oa export.Aggregator, desc *metric.Descriptor) error {
+	o, _ := oa.(*Aggregator)
+	if o == nil {
+		return aggregator.NewInconsistentAggregatorError(c, oa)
+	}
+	c.value.AddNumber(desc.NumberKind(), o.value)
+	return nil
+}
+
+func (c *Aggregator) Subtract(opAgg, resAgg export.Aggregator, descriptor *metric.Descriptor) error {
+	op, _ := opAgg.(*Aggregator)
+	if op == nil {
+		return aggregator.NewInconsistentAggregatorError(c, opAgg)
+	}
+
+	res, _ := resAgg.(*Aggregator)
+	if res == nil {
+		return aggregator.NewInconsistentAggregatorError(c, resAgg)
+	}
+
+	res.value = c.value
+	res.value.AddNumber(descriptor.NumberKind(), number.NewNumberSignChange(descriptor.NumberKind(), op.value))
+	return nil
+}

vendor/go.opentelemetry.io/otel/sdk/metric/atomicfields.go

@@ -0,0 +1,24 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package metric // import "go.opentelemetry.io/otel/sdk/metric"
+
+import "unsafe"
+
+func AtomicFieldOffsets() map[string]uintptr {
+	return map[string]uintptr{
+		"record.refMapped.value": unsafe.Offsetof(record{}.refMapped.value),
+		"record.updateCount":     unsafe.Offsetof(record{}.updateCount),
+	}
+}

vendor/go.opentelemetry.io/otel/sdk/metric/controller/basic/config.go

@@ -0,0 +1,122 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package basic // import "go.opentelemetry.io/otel/sdk/metric/controller/basic"
+
+import (
+	"time"
+
+	export "go.opentelemetry.io/otel/sdk/export/metric"
+	"go.opentelemetry.io/otel/sdk/resource"
+)
+
+// Config contains configuration for a basic Controller.
+type Config struct {
+	// Resource is the OpenTelemetry resource associated with all Meters
+	// created by the Controller.
+	Resource *resource.Resource
+
+	// CollectPeriod is the interval between calls to Collect a
+	// checkpoint.
+	//
+	// When pulling metrics and not exporting, this is the minimum
+	// time between calls to Collect.  In a pull-only
+	// configuration, collection is performed on demand; set
+	// CollectPeriod to 0 always recompute the export record set.
+	//
+	// When exporting metrics, this must be > 0.
+	//
+	// Default value is 10s.
+	CollectPeriod time.Duration
+
+	// CollectTimeout is the timeout of the Context passed to
+	// Collect() and subsequently to Observer instrument callbacks.
+	//
+	// Default value is 10s.  If zero, no Collect timeout is applied.
+	CollectTimeout time.Duration
+
+	// Exporter is used for exporting metric data.
+	//
+	// Note: Exporters such as Prometheus that pull data do not implement
+	// export.Exporter.  These will directly call Collect() and ForEach().
+	Exporter export.Exporter
+
+	// PushTimeout is the timeout of the Context when a exporter is configured.
+	//
+	// Default value is 10s.  If zero, no Export timeout is applied.
+	PushTimeout time.Duration
+}
+
+// Option is the interface that applies the value to a configuration option.
+type Option interface {
+	// Apply sets the Option value of a Config.
+	Apply(*Config)
+}
+
+// WithResource sets the Resource configuration option of a Config by merging it
+// with the Resource configuration in the environment.
+func WithResource(r *resource.Resource) Option {
+	res := resource.Merge(resource.Environment(), r)
+	return resourceOption{res}
+}
+
+type resourceOption struct{ *resource.Resource }
+
+func (o resourceOption) Apply(config *Config) {
+	config.Resource = o.Resource
+}
+
+// WithCollectPeriod sets the CollectPeriod configuration option of a Config.
+func WithCollectPeriod(period time.Duration) Option {
+	return collectPeriodOption(period)
+}
+
+type collectPeriodOption time.Duration
+
+func (o collectPeriodOption) Apply(config *Config) {
+	config.CollectPeriod = time.Duration(o)
+}
+
+// WithCollectTimeout sets the CollectTimeout configuration option of a Config.
+func WithCollectTimeout(timeout time.Duration) Option {
+	return collectTimeoutOption(timeout)
+}
+
+type collectTimeoutOption time.Duration
+
+func (o collectTimeoutOption) Apply(config *Config) {
+	config.CollectTimeout = time.Duration(o)
+}
+
+// WithExporter sets the exporter configuration option of a Config.
+func WithExporter(exporter export.Exporter) Option {
+	return exporterOption{exporter}
+}
+
+type exporterOption struct{ exporter export.Exporter }
+
+func (o exporterOption) Apply(config *Config) {
+	config.Exporter = o.exporter
+}
+
+// WithPushTimeout sets the PushTimeout configuration option of a Config.
+func WithPushTimeout(timeout time.Duration) Option {
+	return pushTimeoutOption(timeout)
+}
+
+type pushTimeoutOption time.Duration
+
+func (o pushTimeoutOption) Apply(config *Config) {
+	config.PushTimeout = time.Duration(o)
+}

vendor/go.opentelemetry.io/otel/sdk/metric/controller/basic/controller.go

@@ -0,0 +1,312 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package basic // import "go.opentelemetry.io/otel/sdk/metric/controller/basic"
+
+import (
+	"context"
+	"fmt"
+	"sync"
+	"time"
+
+	"go.opentelemetry.io/otel"
+	"go.opentelemetry.io/otel/metric"
+	"go.opentelemetry.io/otel/metric/registry"
+	export "go.opentelemetry.io/otel/sdk/export/metric"
+	sdk "go.opentelemetry.io/otel/sdk/metric"
+	controllerTime "go.opentelemetry.io/otel/sdk/metric/controller/time"
+	"go.opentelemetry.io/otel/sdk/resource"
+)
+
+// DefaultPeriod is used for:
+//
+// - the minimum time between calls to Collect()
+// - the timeout for Export()
+// - the timeout for Collect().
+const DefaultPeriod = 10 * time.Second
+
+// ErrControllerStarted indicates that a controller was started more
+// than once.
+var ErrControllerStarted = fmt.Errorf("controller already started")
+
+// Controller organizes and synchronizes collection of metric data in
+// both "pull" and "push" configurations.  This supports two distinct
+// modes:
+//
+// - Push and Pull: Start() must be called to begin calling the exporter;
+//   Collect() is called periodically by a background thread after starting
+//   the controller.
+// - Pull-Only: Start() is optional in this case, to call Collect periodically.
+//   If Start() is not called, Collect() can be called manually to initiate
+//   collection
+//
+// The controller supports mixing push and pull access to metric data
+// using the export.CheckpointSet RWLock interface.  Collection will
+// be blocked by a pull request in the basic controller.
+type Controller struct {
+	lock         sync.Mutex
+	accumulator  *sdk.Accumulator
+	provider     *registry.MeterProvider
+	checkpointer export.Checkpointer
+	exporter     export.Exporter
+	wg           sync.WaitGroup
+	stopCh       chan struct{}
+	clock        controllerTime.Clock
+	ticker       controllerTime.Ticker
+
+	collectPeriod  time.Duration
+	collectTimeout time.Duration
+	pushTimeout    time.Duration
+
+	// collectedTime is used only in configurations with no
+	// exporter, when ticker != nil.
+	collectedTime time.Time
+}
+
+// New constructs a Controller using the provided checkpointer and
+// options (including optional exporter) to configure a metric
+// export pipeline.
+func New(checkpointer export.Checkpointer, opts ...Option) *Controller {
+	c := &Config{
+		CollectPeriod:  DefaultPeriod,
+		CollectTimeout: DefaultPeriod,
+		PushTimeout:    DefaultPeriod,
+	}
+	for _, opt := range opts {
+		opt.Apply(c)
+	}
+	if c.Resource == nil {
+		c.Resource = resource.Default()
+	}
+
+	impl := sdk.NewAccumulator(
+		checkpointer,
+		c.Resource,
+	)
+	return &Controller{
+		provider:     registry.NewMeterProvider(impl),
+		accumulator:  impl,
+		checkpointer: checkpointer,
+		exporter:     c.Exporter,
+		stopCh:       nil,
+		clock:        controllerTime.RealClock{},
+
+		collectPeriod:  c.CollectPeriod,
+		collectTimeout: c.CollectTimeout,
+		pushTimeout:    c.PushTimeout,
+	}
+}
+
+// SetClock supports setting a mock clock for testing.  This must be
+// called before Start().
+func (c *Controller) SetClock(clock controllerTime.Clock) {
+	c.lock.Lock()
+	defer c.lock.Unlock()
+	c.clock = clock
+}
+
+// MeterProvider returns a MeterProvider instance for this controller.
+func (c *Controller) MeterProvider() metric.MeterProvider {
+	return c.provider
+}
+
+// Start begins a ticker that periodically collects and exports
+// metrics with the configured interval.  This is required for calling
+// a configured Exporter (see WithExporter) and is otherwise optional
+// when only pulling metric data.
+//
+// The passed context is passed to Collect() and subsequently to
+// asynchronous instrument callbacks.  Returns an error when the
+// controller was already started.
+//
+// Note that it is not necessary to Start a controller when only
+// pulling data; use the Collect() and ForEach() methods directly in
+// this case.
+func (c *Controller) Start(ctx context.Context) error {
+	c.lock.Lock()
+	defer c.lock.Unlock()
+
+	if c.stopCh != nil {
+		return ErrControllerStarted
+	}
+
+	c.wg.Add(1)
+	c.stopCh = make(chan struct{})
+	c.ticker = c.clock.Ticker(c.collectPeriod)
+	go c.runTicker(ctx, c.stopCh)
+	return nil
+}
+
+// Stop waits for the background goroutine to return and then collects
+// and exports metrics one last time before returning.  The passed
+// context is passed to the final Collect() and subsequently to the
+// final asynchronous instruments.
+//
+// Note that Stop() will not cancel an ongoing collection or export.
+func (c *Controller) Stop(ctx context.Context) error {
+	c.lock.Lock()
+	defer c.lock.Unlock()
+
+	if c.stopCh == nil {
+		return nil
+	}
+
+	close(c.stopCh)
+	c.stopCh = nil
+	c.wg.Wait()
+	c.ticker.Stop()
+	c.ticker = nil
+
+	return c.collect(ctx)
+}
+
+// runTicker collection on ticker events until the stop channel is closed.
+func (c *Controller) runTicker(ctx context.Context, stopCh chan struct{}) {
+	defer c.wg.Done()
+	for {
+		select {
+		case <-stopCh:
+			return
+		case <-c.ticker.C():
+			if err := c.collect(ctx); err != nil {
+				otel.Handle(err)
+			}
+		}
+	}
+}
+
+// collect computes a checkpoint and optionally exports it.
+func (c *Controller) collect(ctx context.Context) error {
+	if err := c.checkpoint(ctx, func() bool {
+		return true
+	}); err != nil {
+		return err
+	}
+	if c.exporter == nil {
+		return nil
+	}
+	// Note: this is not subject to collectTimeout.  This blocks the next
+	// collection despite collectTimeout because it holds a lock.
+	if err := c.export(ctx); err != nil {
+		return err
+	}
+	return nil
+}
+
+// checkpoint calls the Accumulator and Checkpointer interfaces to
+// compute the CheckpointSet.  This applies the configured collection
+// timeout.  Note that this does not try to cancel a Collect or Export
+// when Stop() is called.
+func (c *Controller) checkpoint(ctx context.Context, cond func() bool) error {
+	ckpt := c.checkpointer.CheckpointSet()
+	ckpt.Lock()
+	defer ckpt.Unlock()
+
+	if !cond() {
+		return nil
+	}
+	c.checkpointer.StartCollection()
+
+	if c.collectTimeout > 0 {
+		var cancel context.CancelFunc
+		ctx, cancel = context.WithTimeout(ctx, c.collectTimeout)
+		defer cancel()
+	}
+
+	_ = c.accumulator.Collect(ctx)
+
+	var err error
+	select {
+	case <-ctx.Done():
+		err = ctx.Err()
+	default:
+		// The context wasn't done, ok.
+	}
+
+	// Finish the checkpoint whether the accumulator timed out or not.
+	if cerr := c.checkpointer.FinishCollection(); cerr != nil {
+		if err == nil {
+			err = cerr
+		} else {
+			err = fmt.Errorf("%s: %w", cerr.Error(), err)
+		}
+	}
+
+	return err
+}
+
+// export calls the exporter with a read lock on the CheckpointSet,
+// applying the configured export timeout.
+func (c *Controller) export(ctx context.Context) error {
+	ckpt := c.checkpointer.CheckpointSet()
+	ckpt.RLock()
+	defer ckpt.RUnlock()
+
+	if c.pushTimeout > 0 {
+		var cancel context.CancelFunc
+		ctx, cancel = context.WithTimeout(ctx, c.pushTimeout)
+		defer cancel()
+	}
+
+	return c.exporter.Export(ctx, ckpt)
+}
+
+// Foreach gives the caller read-locked access to the current
+// export.CheckpointSet.
+func (c *Controller) ForEach(ks export.ExportKindSelector, f func(export.Record) error) error {
+	ckpt := c.checkpointer.CheckpointSet()
+	ckpt.RLock()
+	defer ckpt.RUnlock()
+
+	return ckpt.ForEach(ks, f)
+}
+
+// IsRunning returns true if the controller was started via Start(),
+// indicating that the current export.CheckpointSet is being kept
+// up-to-date.
+func (c *Controller) IsRunning() bool {
+	c.lock.Lock()
+	defer c.lock.Unlock()
+	return c.ticker != nil
+}
+
+// Collect requests a collection.  The collection will be skipped if
+// the last collection is aged less than the configured collection
+// period.
+func (c *Controller) Collect(ctx context.Context) error {
+	if c.IsRunning() {
+		// When there's a non-nil ticker, there's a goroutine
+		// computing checkpoints with the collection period.
+		return ErrControllerStarted
+	}
+
+	return c.checkpoint(ctx, c.shouldCollect)
+}
+
+// shouldCollect returns true if the collector should collect now,
+// based on the timestamp, the last collection time, and the
+// configured period.
+func (c *Controller) shouldCollect() bool {
+	// This is called with the CheckpointSet exclusive
+	// lock held.
+	if c.collectPeriod == 0 {
+		return true
+	}
+	now := c.clock.Now()
+	if now.Sub(c.collectedTime) < c.collectPeriod {
+		return false
+	}
+	c.collectedTime = now
+	return true
+}

vendor/go.opentelemetry.io/otel/sdk/metric/controller/time/time.go

@@ -0,0 +1,59 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package time // import "go.opentelemetry.io/otel/sdk/metric/controller/time"
+
+import (
+	"time"
+	lib "time"
+)
+
+// Several types below are created to match "github.com/benbjohnson/clock"
+// so that it remains a test-only dependency.
+
+type Clock interface {
+	Now() lib.Time
+	Ticker(duration lib.Duration) Ticker
+}
+
+type Ticker interface {
+	Stop()
+	C() <-chan lib.Time
+}
+
+type RealClock struct {
+}
+
+type RealTicker struct {
+	ticker *lib.Ticker
+}
+
+var _ Clock = RealClock{}
+var _ Ticker = RealTicker{}
+
+func (RealClock) Now() time.Time {
+	return time.Now()
+}
+
+func (RealClock) Ticker(period time.Duration) Ticker {
+	return RealTicker{time.NewTicker(period)}
+}
+
+func (t RealTicker) Stop() {
+	t.ticker.Stop()
+}
+
+func (t RealTicker) C() <-chan time.Time {
+	return t.ticker.C
+}

vendor/go.opentelemetry.io/otel/sdk/metric/doc.go

@@ -0,0 +1,141 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+/*
+Package metric implements the OpenTelemetry metric API.
+
+This package is currently in a pre-GA phase. Backwards incompatible changes
+may be introduced in subsequent minor version releases as we work to track the
+evolving OpenTelemetry specification and user feedback.
+
+The Accumulator type supports configurable metrics export behavior through a
+collection of export interfaces that support various export strategies,
+described below.
+
+The OpenTelemetry metric API consists of methods for constructing synchronous
+and asynchronous instruments.  There are two constructors per instrument for
+the two kinds of number (int64, float64).
+
+Synchronous instruments are managed by a sync.Map containing a *record
+with the current state for each synchronous instrument.  A bound
+instrument encapsulates a direct pointer to the record, allowing
+bound metric events to bypass a sync.Map lookup.  A lock-free
+algorithm is used to protect against races when adding and removing
+items from the sync.Map.
+
+Asynchronous instruments are managed by an internal
+AsyncInstrumentState, which coordinates calling batch and single
+instrument callbacks.
+
+Internal Structure
+
+Each observer also has its own kind of record stored in the SDK. This
+record contains a set of recorders for every specific label set used in the
+callback.
+
+A sync.Map maintains the mapping of current instruments and label sets to
+internal records.  To create a new bound instrument, the SDK consults the Map to
+locate an existing record, otherwise it constructs a new record.  The SDK
+maintains a count of the number of references to each record, ensuring
+that records are not reclaimed from the Map while they are still active
+from the user's perspective.
+
+Metric collection is performed via a single-threaded call to Collect that
+sweeps through all records in the SDK, checkpointing their state.  When a
+record is discovered that has no references and has not been updated since
+the prior collection pass, it is removed from the Map.
+
+Both synchronous and asynchronous instruments have an associated
+aggregator, which maintains the current state resulting from all metric
+events since its last checkpoint.  Aggregators may be lock-free or they may
+use locking, but they should expect to be called concurrently.  Aggregators
+must be capable of merging with another aggregator of the same type.
+
+Export Pipeline
+
+While the SDK serves to maintain a current set of records and
+coordinate collection, the behavior of a metrics export pipeline is
+configured through the export types in
+go.opentelemetry.io/otel/sdk/export/metric.  It is important to keep
+in mind the context these interfaces are called from.  There are two
+contexts, instrumentation context, where a user-level goroutine that
+enters the SDK resulting in a new record, and collection context,
+where a system-level thread performs a collection pass through the
+SDK.
+
+Descriptor is a struct that describes the metric instrument to the
+export pipeline, containing the name, units, description, metric kind,
+number kind (int64 or float64).  A Descriptor accompanies metric data
+as it passes through the export pipeline.
+
+The AggregatorSelector interface supports choosing the method of
+aggregation to apply to a particular instrument, by delegating the
+construction of an Aggregator to this interface.  Given the Descriptor,
+the AggregatorFor method returns an implementation of Aggregator.  If this
+interface returns nil, the metric will be disabled.  The aggregator should
+be matched to the capabilities of the exporter.  Selecting the aggregator
+for Adding instruments is relatively straightforward, but many options
+are available for aggregating distributions from Grouping instruments.
+
+Aggregator is an interface which implements a concrete strategy for
+aggregating metric updates.  Several Aggregator implementations are
+provided by the SDK.  Aggregators may be lock-free or use locking,
+depending on their structure and semantics.  Aggregators implement an
+Update method, called in instrumentation context, to receive a single
+metric event.  Aggregators implement a Checkpoint method, called in
+collection context, to save a checkpoint of the current state.
+Aggregators implement a Merge method, also called in collection
+context, that combines state from two aggregators into one.  Each SDK
+record has an associated aggregator.
+
+Processor is an interface which sits between the SDK and an exporter.
+The Processor embeds an AggregatorSelector, used by the SDK to assign
+new Aggregators.  The Processor supports a Process() API for submitting
+checkpointed aggregators to the processor, and a CheckpointSet() API
+for producing a complete checkpoint for the exporter.  Two default
+Processor implementations are provided, the "defaultkeys" Processor groups
+aggregate metrics by their recommended Descriptor.Keys(), the
+"simple" Processor aggregates metrics at full dimensionality.
+
+LabelEncoder is an optional optimization that allows an exporter to
+provide the serialization logic for labels.  This allows avoiding
+duplicate serialization of labels, once as a unique key in the SDK (or
+Processor) and once in the exporter.
+
+CheckpointSet is an interface between the Processor and the Exporter.
+After completing a collection pass, the Processor.CheckpointSet() method
+returns a CheckpointSet, which the Exporter uses to iterate over all
+the updated metrics.
+
+Record is a struct containing the state of an individual exported
+metric.  This is the result of one collection interface for one
+instrument and one label set.
+
+Labels is a struct containing an ordered set of labels, the
+corresponding unique encoding, and the encoder that produced it.
+
+Exporter is the final stage of an export pipeline.  It is called with
+a CheckpointSet capable of enumerating all the updated metrics.
+
+Controller is not an export interface per se, but it orchestrates the
+export pipeline.  For example, a "push" controller will establish a
+periodic timer to regularly collect and export metrics.  A "pull"
+controller will await a pull request before initiating metric
+collection.  Either way, the job of the controller is to call the SDK
+Collect() method, then read the checkpoint, then invoke the exporter.
+Controllers are expected to implement the public metric.MeterProvider
+API, meaning they can be installed as the global Meter provider.
+
+*/
+package metric // import "go.opentelemetry.io/otel/sdk/metric"