mirror of
https://github.com/ceph/ceph-csi.git
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9eaa55506f
This commit updates controller-runtime to v0.9.2 and makes changes in persistentvolume.go to add context to various functions and function calls made here instead of context.TODO(). Signed-off-by: Rakshith R <rar@redhat.com>
745 lines
24 KiB
Go
745 lines
24 KiB
Go
// Copyright 2014 The Prometheus Authors
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package prometheus
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import (
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"fmt"
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"math"
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"runtime"
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"sort"
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"sync"
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"sync/atomic"
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"time"
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"github.com/beorn7/perks/quantile"
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//nolint:staticcheck // Ignore SA1019. Need to keep deprecated package for compatibility.
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"github.com/golang/protobuf/proto"
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dto "github.com/prometheus/client_model/go"
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)
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// quantileLabel is used for the label that defines the quantile in a
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// summary.
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const quantileLabel = "quantile"
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// A Summary captures individual observations from an event or sample stream and
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// summarizes them in a manner similar to traditional summary statistics: 1. sum
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// of observations, 2. observation count, 3. rank estimations.
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//
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// A typical use-case is the observation of request latencies. By default, a
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// Summary provides the median, the 90th and the 99th percentile of the latency
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// as rank estimations. However, the default behavior will change in the
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// upcoming v1.0.0 of the library. There will be no rank estimations at all by
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// default. For a sane transition, it is recommended to set the desired rank
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// estimations explicitly.
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//
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// Note that the rank estimations cannot be aggregated in a meaningful way with
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// the Prometheus query language (i.e. you cannot average or add them). If you
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// need aggregatable quantiles (e.g. you want the 99th percentile latency of all
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// queries served across all instances of a service), consider the Histogram
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// metric type. See the Prometheus documentation for more details.
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//
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// To create Summary instances, use NewSummary.
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type Summary interface {
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Metric
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Collector
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// Observe adds a single observation to the summary. Observations are
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// usually positive or zero. Negative observations are accepted but
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// prevent current versions of Prometheus from properly detecting
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// counter resets in the sum of observations. See
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// https://prometheus.io/docs/practices/histograms/#count-and-sum-of-observations
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// for details.
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Observe(float64)
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}
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var errQuantileLabelNotAllowed = fmt.Errorf(
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"%q is not allowed as label name in summaries", quantileLabel,
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)
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// Default values for SummaryOpts.
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const (
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// DefMaxAge is the default duration for which observations stay
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// relevant.
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DefMaxAge time.Duration = 10 * time.Minute
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// DefAgeBuckets is the default number of buckets used to calculate the
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// age of observations.
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DefAgeBuckets = 5
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// DefBufCap is the standard buffer size for collecting Summary observations.
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DefBufCap = 500
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)
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// SummaryOpts bundles the options for creating a Summary metric. It is
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// mandatory to set Name to a non-empty string. While all other fields are
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// optional and can safely be left at their zero value, it is recommended to set
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// a help string and to explicitly set the Objectives field to the desired value
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// as the default value will change in the upcoming v1.0.0 of the library.
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type SummaryOpts struct {
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// Namespace, Subsystem, and Name are components of the fully-qualified
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// name of the Summary (created by joining these components with
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// "_"). Only Name is mandatory, the others merely help structuring the
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// name. Note that the fully-qualified name of the Summary must be a
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// valid Prometheus metric name.
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Namespace string
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Subsystem string
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Name string
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// Help provides information about this Summary.
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//
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// Metrics with the same fully-qualified name must have the same Help
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// string.
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Help string
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// ConstLabels are used to attach fixed labels to this metric. Metrics
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// with the same fully-qualified name must have the same label names in
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// their ConstLabels.
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//
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// Due to the way a Summary is represented in the Prometheus text format
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// and how it is handled by the Prometheus server internally, “quantile”
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// is an illegal label name. Construction of a Summary or SummaryVec
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// will panic if this label name is used in ConstLabels.
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//
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// ConstLabels are only used rarely. In particular, do not use them to
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// attach the same labels to all your metrics. Those use cases are
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// better covered by target labels set by the scraping Prometheus
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// server, or by one specific metric (e.g. a build_info or a
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// machine_role metric). See also
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// https://prometheus.io/docs/instrumenting/writing_exporters/#target-labels-not-static-scraped-labels
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ConstLabels Labels
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// Objectives defines the quantile rank estimates with their respective
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// absolute error. If Objectives[q] = e, then the value reported for q
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// will be the φ-quantile value for some φ between q-e and q+e. The
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// default value is an empty map, resulting in a summary without
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// quantiles.
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Objectives map[float64]float64
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// MaxAge defines the duration for which an observation stays relevant
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// for the summary. Only applies to pre-calculated quantiles, does not
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// apply to _sum and _count. Must be positive. The default value is
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// DefMaxAge.
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MaxAge time.Duration
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// AgeBuckets is the number of buckets used to exclude observations that
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// are older than MaxAge from the summary. A higher number has a
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// resource penalty, so only increase it if the higher resolution is
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// really required. For very high observation rates, you might want to
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// reduce the number of age buckets. With only one age bucket, you will
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// effectively see a complete reset of the summary each time MaxAge has
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// passed. The default value is DefAgeBuckets.
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AgeBuckets uint32
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// BufCap defines the default sample stream buffer size. The default
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// value of DefBufCap should suffice for most uses. If there is a need
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// to increase the value, a multiple of 500 is recommended (because that
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// is the internal buffer size of the underlying package
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// "github.com/bmizerany/perks/quantile").
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BufCap uint32
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}
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// Problem with the sliding-window decay algorithm... The Merge method of
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// perk/quantile is actually not working as advertised - and it might be
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// unfixable, as the underlying algorithm is apparently not capable of merging
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// summaries in the first place. To avoid using Merge, we are currently adding
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// observations to _each_ age bucket, i.e. the effort to add a sample is
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// essentially multiplied by the number of age buckets. When rotating age
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// buckets, we empty the previous head stream. On scrape time, we simply take
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// the quantiles from the head stream (no merging required). Result: More effort
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// on observation time, less effort on scrape time, which is exactly the
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// opposite of what we try to accomplish, but at least the results are correct.
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//
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// The quite elegant previous contraption to merge the age buckets efficiently
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// on scrape time (see code up commit 6b9530d72ea715f0ba612c0120e6e09fbf1d49d0)
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// can't be used anymore.
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// NewSummary creates a new Summary based on the provided SummaryOpts.
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func NewSummary(opts SummaryOpts) Summary {
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return newSummary(
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NewDesc(
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BuildFQName(opts.Namespace, opts.Subsystem, opts.Name),
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opts.Help,
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nil,
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opts.ConstLabels,
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),
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opts,
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)
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}
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func newSummary(desc *Desc, opts SummaryOpts, labelValues ...string) Summary {
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if len(desc.variableLabels) != len(labelValues) {
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panic(makeInconsistentCardinalityError(desc.fqName, desc.variableLabels, labelValues))
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}
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for _, n := range desc.variableLabels {
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if n == quantileLabel {
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panic(errQuantileLabelNotAllowed)
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}
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}
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for _, lp := range desc.constLabelPairs {
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if lp.GetName() == quantileLabel {
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panic(errQuantileLabelNotAllowed)
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}
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}
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if opts.Objectives == nil {
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opts.Objectives = map[float64]float64{}
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}
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if opts.MaxAge < 0 {
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panic(fmt.Errorf("illegal max age MaxAge=%v", opts.MaxAge))
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}
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if opts.MaxAge == 0 {
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opts.MaxAge = DefMaxAge
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}
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if opts.AgeBuckets == 0 {
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opts.AgeBuckets = DefAgeBuckets
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}
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if opts.BufCap == 0 {
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opts.BufCap = DefBufCap
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}
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if len(opts.Objectives) == 0 {
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// Use the lock-free implementation of a Summary without objectives.
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s := &noObjectivesSummary{
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desc: desc,
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labelPairs: MakeLabelPairs(desc, labelValues),
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counts: [2]*summaryCounts{{}, {}},
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}
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s.init(s) // Init self-collection.
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return s
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}
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s := &summary{
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desc: desc,
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objectives: opts.Objectives,
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sortedObjectives: make([]float64, 0, len(opts.Objectives)),
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labelPairs: MakeLabelPairs(desc, labelValues),
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hotBuf: make([]float64, 0, opts.BufCap),
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coldBuf: make([]float64, 0, opts.BufCap),
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streamDuration: opts.MaxAge / time.Duration(opts.AgeBuckets),
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}
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s.headStreamExpTime = time.Now().Add(s.streamDuration)
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s.hotBufExpTime = s.headStreamExpTime
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for i := uint32(0); i < opts.AgeBuckets; i++ {
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s.streams = append(s.streams, s.newStream())
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}
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s.headStream = s.streams[0]
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for qu := range s.objectives {
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s.sortedObjectives = append(s.sortedObjectives, qu)
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}
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sort.Float64s(s.sortedObjectives)
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s.init(s) // Init self-collection.
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return s
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}
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type summary struct {
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selfCollector
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bufMtx sync.Mutex // Protects hotBuf and hotBufExpTime.
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mtx sync.Mutex // Protects every other moving part.
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// Lock bufMtx before mtx if both are needed.
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desc *Desc
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objectives map[float64]float64
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sortedObjectives []float64
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labelPairs []*dto.LabelPair
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sum float64
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cnt uint64
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hotBuf, coldBuf []float64
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streams []*quantile.Stream
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streamDuration time.Duration
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headStream *quantile.Stream
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headStreamIdx int
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headStreamExpTime, hotBufExpTime time.Time
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}
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func (s *summary) Desc() *Desc {
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return s.desc
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}
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func (s *summary) Observe(v float64) {
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s.bufMtx.Lock()
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defer s.bufMtx.Unlock()
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now := time.Now()
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if now.After(s.hotBufExpTime) {
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s.asyncFlush(now)
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}
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s.hotBuf = append(s.hotBuf, v)
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if len(s.hotBuf) == cap(s.hotBuf) {
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s.asyncFlush(now)
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}
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}
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func (s *summary) Write(out *dto.Metric) error {
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sum := &dto.Summary{}
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qs := make([]*dto.Quantile, 0, len(s.objectives))
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s.bufMtx.Lock()
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s.mtx.Lock()
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// Swap bufs even if hotBuf is empty to set new hotBufExpTime.
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s.swapBufs(time.Now())
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s.bufMtx.Unlock()
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s.flushColdBuf()
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sum.SampleCount = proto.Uint64(s.cnt)
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sum.SampleSum = proto.Float64(s.sum)
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for _, rank := range s.sortedObjectives {
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var q float64
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if s.headStream.Count() == 0 {
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q = math.NaN()
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} else {
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q = s.headStream.Query(rank)
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}
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qs = append(qs, &dto.Quantile{
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Quantile: proto.Float64(rank),
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Value: proto.Float64(q),
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})
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}
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s.mtx.Unlock()
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if len(qs) > 0 {
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sort.Sort(quantSort(qs))
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}
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sum.Quantile = qs
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out.Summary = sum
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out.Label = s.labelPairs
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return nil
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}
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func (s *summary) newStream() *quantile.Stream {
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return quantile.NewTargeted(s.objectives)
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}
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// asyncFlush needs bufMtx locked.
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func (s *summary) asyncFlush(now time.Time) {
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s.mtx.Lock()
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s.swapBufs(now)
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// Unblock the original goroutine that was responsible for the mutation
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// that triggered the compaction. But hold onto the global non-buffer
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// state mutex until the operation finishes.
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go func() {
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s.flushColdBuf()
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s.mtx.Unlock()
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}()
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}
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// rotateStreams needs mtx AND bufMtx locked.
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func (s *summary) maybeRotateStreams() {
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for !s.hotBufExpTime.Equal(s.headStreamExpTime) {
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s.headStream.Reset()
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s.headStreamIdx++
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if s.headStreamIdx >= len(s.streams) {
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s.headStreamIdx = 0
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}
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s.headStream = s.streams[s.headStreamIdx]
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s.headStreamExpTime = s.headStreamExpTime.Add(s.streamDuration)
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}
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}
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// flushColdBuf needs mtx locked.
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func (s *summary) flushColdBuf() {
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for _, v := range s.coldBuf {
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for _, stream := range s.streams {
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stream.Insert(v)
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}
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s.cnt++
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s.sum += v
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}
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s.coldBuf = s.coldBuf[0:0]
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s.maybeRotateStreams()
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}
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// swapBufs needs mtx AND bufMtx locked, coldBuf must be empty.
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func (s *summary) swapBufs(now time.Time) {
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if len(s.coldBuf) != 0 {
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panic("coldBuf is not empty")
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}
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s.hotBuf, s.coldBuf = s.coldBuf, s.hotBuf
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// hotBuf is now empty and gets new expiration set.
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for now.After(s.hotBufExpTime) {
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s.hotBufExpTime = s.hotBufExpTime.Add(s.streamDuration)
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}
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}
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type summaryCounts struct {
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// sumBits contains the bits of the float64 representing the sum of all
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// observations. sumBits and count have to go first in the struct to
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// guarantee alignment for atomic operations.
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// http://golang.org/pkg/sync/atomic/#pkg-note-BUG
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sumBits uint64
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count uint64
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}
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type noObjectivesSummary struct {
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// countAndHotIdx enables lock-free writes with use of atomic updates.
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// The most significant bit is the hot index [0 or 1] of the count field
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// below. Observe calls update the hot one. All remaining bits count the
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// number of Observe calls. Observe starts by incrementing this counter,
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// and finish by incrementing the count field in the respective
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// summaryCounts, as a marker for completion.
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//
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// Calls of the Write method (which are non-mutating reads from the
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// perspective of the summary) swap the hot–cold under the writeMtx
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// lock. A cooldown is awaited (while locked) by comparing the number of
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// observations with the initiation count. Once they match, then the
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// last observation on the now cool one has completed. All cool fields must
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// be merged into the new hot before releasing writeMtx.
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// Fields with atomic access first! See alignment constraint:
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// http://golang.org/pkg/sync/atomic/#pkg-note-BUG
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countAndHotIdx uint64
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selfCollector
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desc *Desc
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writeMtx sync.Mutex // Only used in the Write method.
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// Two counts, one is "hot" for lock-free observations, the other is
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// "cold" for writing out a dto.Metric. It has to be an array of
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// pointers to guarantee 64bit alignment of the histogramCounts, see
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// http://golang.org/pkg/sync/atomic/#pkg-note-BUG.
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counts [2]*summaryCounts
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labelPairs []*dto.LabelPair
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}
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func (s *noObjectivesSummary) Desc() *Desc {
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return s.desc
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}
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func (s *noObjectivesSummary) Observe(v float64) {
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// We increment h.countAndHotIdx so that the counter in the lower
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// 63 bits gets incremented. At the same time, we get the new value
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// back, which we can use to find the currently-hot counts.
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n := atomic.AddUint64(&s.countAndHotIdx, 1)
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hotCounts := s.counts[n>>63]
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for {
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oldBits := atomic.LoadUint64(&hotCounts.sumBits)
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newBits := math.Float64bits(math.Float64frombits(oldBits) + v)
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if atomic.CompareAndSwapUint64(&hotCounts.sumBits, oldBits, newBits) {
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break
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}
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}
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// Increment count last as we take it as a signal that the observation
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// is complete.
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atomic.AddUint64(&hotCounts.count, 1)
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}
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func (s *noObjectivesSummary) Write(out *dto.Metric) error {
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// For simplicity, we protect this whole method by a mutex. It is not in
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// the hot path, i.e. Observe is called much more often than Write. The
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// complication of making Write lock-free isn't worth it, if possible at
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// all.
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s.writeMtx.Lock()
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defer s.writeMtx.Unlock()
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// Adding 1<<63 switches the hot index (from 0 to 1 or from 1 to 0)
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// without touching the count bits. See the struct comments for a full
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// description of the algorithm.
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n := atomic.AddUint64(&s.countAndHotIdx, 1<<63)
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// count is contained unchanged in the lower 63 bits.
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count := n & ((1 << 63) - 1)
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// The most significant bit tells us which counts is hot. The complement
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// is thus the cold one.
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hotCounts := s.counts[n>>63]
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coldCounts := s.counts[(^n)>>63]
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// Await cooldown.
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for count != atomic.LoadUint64(&coldCounts.count) {
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runtime.Gosched() // Let observations get work done.
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}
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sum := &dto.Summary{
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SampleCount: proto.Uint64(count),
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SampleSum: proto.Float64(math.Float64frombits(atomic.LoadUint64(&coldCounts.sumBits))),
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}
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out.Summary = sum
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out.Label = s.labelPairs
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// Finally add all the cold counts to the new hot counts and reset the cold counts.
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atomic.AddUint64(&hotCounts.count, count)
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atomic.StoreUint64(&coldCounts.count, 0)
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for {
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oldBits := atomic.LoadUint64(&hotCounts.sumBits)
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newBits := math.Float64bits(math.Float64frombits(oldBits) + sum.GetSampleSum())
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if atomic.CompareAndSwapUint64(&hotCounts.sumBits, oldBits, newBits) {
|
||
atomic.StoreUint64(&coldCounts.sumBits, 0)
|
||
break
|
||
}
|
||
}
|
||
return nil
|
||
}
|
||
|
||
type quantSort []*dto.Quantile
|
||
|
||
func (s quantSort) Len() int {
|
||
return len(s)
|
||
}
|
||
|
||
func (s quantSort) Swap(i, j int) {
|
||
s[i], s[j] = s[j], s[i]
|
||
}
|
||
|
||
func (s quantSort) Less(i, j int) bool {
|
||
return s[i].GetQuantile() < s[j].GetQuantile()
|
||
}
|
||
|
||
// SummaryVec is a Collector that bundles a set of Summaries that all share the
|
||
// same Desc, but have different values for their variable labels. This is used
|
||
// if you want to count the same thing partitioned by various dimensions
|
||
// (e.g. HTTP request latencies, partitioned by status code and method). Create
|
||
// instances with NewSummaryVec.
|
||
type SummaryVec struct {
|
||
*MetricVec
|
||
}
|
||
|
||
// NewSummaryVec creates a new SummaryVec based on the provided SummaryOpts and
|
||
// partitioned by the given label names.
|
||
//
|
||
// Due to the way a Summary is represented in the Prometheus text format and how
|
||
// it is handled by the Prometheus server internally, “quantile” is an illegal
|
||
// label name. NewSummaryVec will panic if this label name is used.
|
||
func NewSummaryVec(opts SummaryOpts, labelNames []string) *SummaryVec {
|
||
for _, ln := range labelNames {
|
||
if ln == quantileLabel {
|
||
panic(errQuantileLabelNotAllowed)
|
||
}
|
||
}
|
||
desc := NewDesc(
|
||
BuildFQName(opts.Namespace, opts.Subsystem, opts.Name),
|
||
opts.Help,
|
||
labelNames,
|
||
opts.ConstLabels,
|
||
)
|
||
return &SummaryVec{
|
||
MetricVec: NewMetricVec(desc, func(lvs ...string) Metric {
|
||
return newSummary(desc, opts, lvs...)
|
||
}),
|
||
}
|
||
}
|
||
|
||
// GetMetricWithLabelValues returns the Summary for the given slice of label
|
||
// values (same order as the variable labels in Desc). If that combination of
|
||
// label values is accessed for the first time, a new Summary is created.
|
||
//
|
||
// It is possible to call this method without using the returned Summary to only
|
||
// create the new Summary but leave it at its starting value, a Summary without
|
||
// any observations.
|
||
//
|
||
// Keeping the Summary for later use is possible (and should be considered if
|
||
// performance is critical), but keep in mind that Reset, DeleteLabelValues and
|
||
// Delete can be used to delete the Summary from the SummaryVec. In that case,
|
||
// the Summary will still exist, but it will not be exported anymore, even if a
|
||
// Summary with the same label values is created later. See also the CounterVec
|
||
// example.
|
||
//
|
||
// An error is returned if the number of label values is not the same as the
|
||
// number of variable labels in Desc (minus any curried labels).
|
||
//
|
||
// Note that for more than one label value, this method is prone to mistakes
|
||
// caused by an incorrect order of arguments. Consider GetMetricWith(Labels) as
|
||
// an alternative to avoid that type of mistake. For higher label numbers, the
|
||
// latter has a much more readable (albeit more verbose) syntax, but it comes
|
||
// with a performance overhead (for creating and processing the Labels map).
|
||
// See also the GaugeVec example.
|
||
func (v *SummaryVec) GetMetricWithLabelValues(lvs ...string) (Observer, error) {
|
||
metric, err := v.MetricVec.GetMetricWithLabelValues(lvs...)
|
||
if metric != nil {
|
||
return metric.(Observer), err
|
||
}
|
||
return nil, err
|
||
}
|
||
|
||
// GetMetricWith returns the Summary for the given Labels map (the label names
|
||
// must match those of the variable labels in Desc). If that label map is
|
||
// accessed for the first time, a new Summary is created. Implications of
|
||
// creating a Summary without using it and keeping the Summary for later use are
|
||
// the same as for GetMetricWithLabelValues.
|
||
//
|
||
// An error is returned if the number and names of the Labels are inconsistent
|
||
// with those of the variable labels in Desc (minus any curried labels).
|
||
//
|
||
// This method is used for the same purpose as
|
||
// GetMetricWithLabelValues(...string). See there for pros and cons of the two
|
||
// methods.
|
||
func (v *SummaryVec) GetMetricWith(labels Labels) (Observer, error) {
|
||
metric, err := v.MetricVec.GetMetricWith(labels)
|
||
if metric != nil {
|
||
return metric.(Observer), err
|
||
}
|
||
return nil, err
|
||
}
|
||
|
||
// WithLabelValues works as GetMetricWithLabelValues, but panics where
|
||
// GetMetricWithLabelValues would have returned an error. Not returning an
|
||
// error allows shortcuts like
|
||
// myVec.WithLabelValues("404", "GET").Observe(42.21)
|
||
func (v *SummaryVec) WithLabelValues(lvs ...string) Observer {
|
||
s, err := v.GetMetricWithLabelValues(lvs...)
|
||
if err != nil {
|
||
panic(err)
|
||
}
|
||
return s
|
||
}
|
||
|
||
// With works as GetMetricWith, but panics where GetMetricWithLabels would have
|
||
// returned an error. Not returning an error allows shortcuts like
|
||
// myVec.With(prometheus.Labels{"code": "404", "method": "GET"}).Observe(42.21)
|
||
func (v *SummaryVec) With(labels Labels) Observer {
|
||
s, err := v.GetMetricWith(labels)
|
||
if err != nil {
|
||
panic(err)
|
||
}
|
||
return s
|
||
}
|
||
|
||
// CurryWith returns a vector curried with the provided labels, i.e. the
|
||
// returned vector has those labels pre-set for all labeled operations performed
|
||
// on it. The cardinality of the curried vector is reduced accordingly. The
|
||
// order of the remaining labels stays the same (just with the curried labels
|
||
// taken out of the sequence – which is relevant for the
|
||
// (GetMetric)WithLabelValues methods). It is possible to curry a curried
|
||
// vector, but only with labels not yet used for currying before.
|
||
//
|
||
// The metrics contained in the SummaryVec are shared between the curried and
|
||
// uncurried vectors. They are just accessed differently. Curried and uncurried
|
||
// vectors behave identically in terms of collection. Only one must be
|
||
// registered with a given registry (usually the uncurried version). The Reset
|
||
// method deletes all metrics, even if called on a curried vector.
|
||
func (v *SummaryVec) CurryWith(labels Labels) (ObserverVec, error) {
|
||
vec, err := v.MetricVec.CurryWith(labels)
|
||
if vec != nil {
|
||
return &SummaryVec{vec}, err
|
||
}
|
||
return nil, err
|
||
}
|
||
|
||
// MustCurryWith works as CurryWith but panics where CurryWith would have
|
||
// returned an error.
|
||
func (v *SummaryVec) MustCurryWith(labels Labels) ObserverVec {
|
||
vec, err := v.CurryWith(labels)
|
||
if err != nil {
|
||
panic(err)
|
||
}
|
||
return vec
|
||
}
|
||
|
||
type constSummary struct {
|
||
desc *Desc
|
||
count uint64
|
||
sum float64
|
||
quantiles map[float64]float64
|
||
labelPairs []*dto.LabelPair
|
||
}
|
||
|
||
func (s *constSummary) Desc() *Desc {
|
||
return s.desc
|
||
}
|
||
|
||
func (s *constSummary) Write(out *dto.Metric) error {
|
||
sum := &dto.Summary{}
|
||
qs := make([]*dto.Quantile, 0, len(s.quantiles))
|
||
|
||
sum.SampleCount = proto.Uint64(s.count)
|
||
sum.SampleSum = proto.Float64(s.sum)
|
||
|
||
for rank, q := range s.quantiles {
|
||
qs = append(qs, &dto.Quantile{
|
||
Quantile: proto.Float64(rank),
|
||
Value: proto.Float64(q),
|
||
})
|
||
}
|
||
|
||
if len(qs) > 0 {
|
||
sort.Sort(quantSort(qs))
|
||
}
|
||
sum.Quantile = qs
|
||
|
||
out.Summary = sum
|
||
out.Label = s.labelPairs
|
||
|
||
return nil
|
||
}
|
||
|
||
// NewConstSummary returns a metric representing a Prometheus summary with fixed
|
||
// values for the count, sum, and quantiles. As those parameters cannot be
|
||
// changed, the returned value does not implement the Summary interface (but
|
||
// only the Metric interface). Users of this package will not have much use for
|
||
// it in regular operations. However, when implementing custom Collectors, it is
|
||
// useful as a throw-away metric that is generated on the fly to send it to
|
||
// Prometheus in the Collect method.
|
||
//
|
||
// quantiles maps ranks to quantile values. For example, a median latency of
|
||
// 0.23s and a 99th percentile latency of 0.56s would be expressed as:
|
||
// map[float64]float64{0.5: 0.23, 0.99: 0.56}
|
||
//
|
||
// NewConstSummary returns an error if the length of labelValues is not
|
||
// consistent with the variable labels in Desc or if Desc is invalid.
|
||
func NewConstSummary(
|
||
desc *Desc,
|
||
count uint64,
|
||
sum float64,
|
||
quantiles map[float64]float64,
|
||
labelValues ...string,
|
||
) (Metric, error) {
|
||
if desc.err != nil {
|
||
return nil, desc.err
|
||
}
|
||
if err := validateLabelValues(labelValues, len(desc.variableLabels)); err != nil {
|
||
return nil, err
|
||
}
|
||
return &constSummary{
|
||
desc: desc,
|
||
count: count,
|
||
sum: sum,
|
||
quantiles: quantiles,
|
||
labelPairs: MakeLabelPairs(desc, labelValues),
|
||
}, nil
|
||
}
|
||
|
||
// MustNewConstSummary is a version of NewConstSummary that panics where
|
||
// NewConstMetric would have returned an error.
|
||
func MustNewConstSummary(
|
||
desc *Desc,
|
||
count uint64,
|
||
sum float64,
|
||
quantiles map[float64]float64,
|
||
labelValues ...string,
|
||
) Metric {
|
||
m, err := NewConstSummary(desc, count, sum, quantiles, labelValues...)
|
||
if err != nil {
|
||
panic(err)
|
||
}
|
||
return m
|
||
}
|