mirror of
https://github.com/ceph/ceph-csi.git
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556 lines
16 KiB
Go
556 lines
16 KiB
Go
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// Copyright The OpenTelemetry Authors
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//
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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 metric // import "go.opentelemetry.io/otel/sdk/metric"
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import (
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"context"
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"fmt"
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"runtime"
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"sync"
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"sync/atomic"
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"go.opentelemetry.io/otel"
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"go.opentelemetry.io/otel/attribute"
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internal "go.opentelemetry.io/otel/internal/metric"
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"go.opentelemetry.io/otel/metric"
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"go.opentelemetry.io/otel/metric/number"
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export "go.opentelemetry.io/otel/sdk/export/metric"
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"go.opentelemetry.io/otel/sdk/metric/aggregator"
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"go.opentelemetry.io/otel/sdk/resource"
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)
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type (
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// Accumulator implements the OpenTelemetry Meter API. The
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// Accumulator is bound to a single export.Processor in
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// `NewAccumulator()`.
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//
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// The Accumulator supports a Collect() API to gather and export
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// current data. Collect() should be arranged according to
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// the processor model. Push-based processors will setup a
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// timer to call Collect() periodically. Pull-based processors
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// will call Collect() when a pull request arrives.
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Accumulator struct {
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// current maps `mapkey` to *record.
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current sync.Map
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// asyncInstruments is a set of
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// `*asyncInstrument` instances
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asyncLock sync.Mutex
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asyncInstruments *internal.AsyncInstrumentState
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// currentEpoch is the current epoch number. It is
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// incremented in `Collect()`.
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currentEpoch int64
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// processor is the configured processor+configuration.
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processor export.Processor
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// collectLock prevents simultaneous calls to Collect().
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collectLock sync.Mutex
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// asyncSortSlice has a single purpose - as a temporary
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// place for sorting during labels creation to avoid
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// allocation. It is cleared after use.
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asyncSortSlice attribute.Sortable
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// resource is applied to all records in this Accumulator.
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resource *resource.Resource
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}
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syncInstrument struct {
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instrument
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}
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// mapkey uniquely describes a metric instrument in terms of
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// its InstrumentID and the encoded form of its labels.
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mapkey struct {
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descriptor *metric.Descriptor
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ordered attribute.Distinct
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}
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// record maintains the state of one metric instrument. Due
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// the use of lock-free algorithms, there may be more than one
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// `record` in existence at a time, although at most one can
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// be referenced from the `Accumulator.current` map.
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record struct {
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// refMapped keeps track of refcounts and the mapping state to the
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// Accumulator.current map.
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refMapped refcountMapped
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// updateCount is incremented on every Update.
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updateCount int64
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// collectedCount is set to updateCount on collection,
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// supports checking for no updates during a round.
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collectedCount int64
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// storage is the stored label set for this record,
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// except in cases where a label set is shared due to
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// batch recording.
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storage attribute.Set
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// labels is the processed label set for this record.
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// this may refer to the `storage` field in another
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// record if this label set is shared resulting from
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// `RecordBatch`.
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labels *attribute.Set
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// sortSlice has a single purpose - as a temporary
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// place for sorting during labels creation to avoid
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// allocation.
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sortSlice attribute.Sortable
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// inst is a pointer to the corresponding instrument.
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inst *syncInstrument
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// current implements the actual RecordOne() API,
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// depending on the type of aggregation. If nil, the
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// metric was disabled by the exporter.
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current export.Aggregator
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checkpoint export.Aggregator
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}
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instrument struct {
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meter *Accumulator
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descriptor metric.Descriptor
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}
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asyncInstrument struct {
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instrument
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// recorders maps ordered labels to the pair of
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// labelset and recorder
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recorders map[attribute.Distinct]*labeledRecorder
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}
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labeledRecorder struct {
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observedEpoch int64
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labels *attribute.Set
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observed export.Aggregator
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}
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)
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var (
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_ metric.MeterImpl = &Accumulator{}
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_ metric.AsyncImpl = &asyncInstrument{}
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_ metric.SyncImpl = &syncInstrument{}
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_ metric.BoundSyncImpl = &record{}
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ErrUninitializedInstrument = fmt.Errorf("use of an uninitialized instrument")
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)
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func (inst *instrument) Descriptor() metric.Descriptor {
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return inst.descriptor
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}
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func (a *asyncInstrument) Implementation() interface{} {
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return a
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}
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func (s *syncInstrument) Implementation() interface{} {
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return s
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}
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func (a *asyncInstrument) observe(num number.Number, labels *attribute.Set) {
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if err := aggregator.RangeTest(num, &a.descriptor); err != nil {
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otel.Handle(err)
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return
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}
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recorder := a.getRecorder(labels)
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if recorder == nil {
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// The instrument is disabled according to the
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// AggregatorSelector.
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return
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}
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if err := recorder.Update(context.Background(), num, &a.descriptor); err != nil {
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otel.Handle(err)
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return
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}
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}
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func (a *asyncInstrument) getRecorder(labels *attribute.Set) export.Aggregator {
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lrec, ok := a.recorders[labels.Equivalent()]
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if ok {
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// Note: SynchronizedMove(nil) can't return an error
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_ = lrec.observed.SynchronizedMove(nil, &a.descriptor)
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lrec.observedEpoch = a.meter.currentEpoch
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a.recorders[labels.Equivalent()] = lrec
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return lrec.observed
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}
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var rec export.Aggregator
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a.meter.processor.AggregatorFor(&a.descriptor, &rec)
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if a.recorders == nil {
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a.recorders = make(map[attribute.Distinct]*labeledRecorder)
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}
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// This may store nil recorder in the map, thus disabling the
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// asyncInstrument for the labelset for good. This is intentional,
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// but will be revisited later.
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a.recorders[labels.Equivalent()] = &labeledRecorder{
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observed: rec,
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labels: labels,
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observedEpoch: a.meter.currentEpoch,
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}
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return rec
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}
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// acquireHandle gets or creates a `*record` corresponding to `kvs`,
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// the input labels. The second argument `labels` is passed in to
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// support re-use of the orderedLabels computed by a previous
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// measurement in the same batch. This performs two allocations
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// in the common case.
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func (s *syncInstrument) acquireHandle(kvs []attribute.KeyValue, labelPtr *attribute.Set) *record {
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var rec *record
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var equiv attribute.Distinct
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if labelPtr == nil {
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// This memory allocation may not be used, but it's
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// needed for the `sortSlice` field, to avoid an
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// allocation while sorting.
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rec = &record{}
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rec.storage = attribute.NewSetWithSortable(kvs, &rec.sortSlice)
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rec.labels = &rec.storage
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equiv = rec.storage.Equivalent()
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} else {
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equiv = labelPtr.Equivalent()
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}
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// Create lookup key for sync.Map (one allocation, as this
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// passes through an interface{})
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mk := mapkey{
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descriptor: &s.descriptor,
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ordered: equiv,
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}
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if actual, ok := s.meter.current.Load(mk); ok {
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// Existing record case.
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existingRec := actual.(*record)
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if existingRec.refMapped.ref() {
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// At this moment it is guaranteed that the entry is in
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// the map and will not be removed.
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return existingRec
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}
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// This entry is no longer mapped, try to add a new entry.
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}
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if rec == nil {
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rec = &record{}
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rec.labels = labelPtr
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}
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rec.refMapped = refcountMapped{value: 2}
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rec.inst = s
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s.meter.processor.AggregatorFor(&s.descriptor, &rec.current, &rec.checkpoint)
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for {
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// Load/Store: there's a memory allocation to place `mk` into
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// an interface here.
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if actual, loaded := s.meter.current.LoadOrStore(mk, rec); loaded {
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// Existing record case. Cannot change rec here because if fail
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// will try to add rec again to avoid new allocations.
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oldRec := actual.(*record)
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if oldRec.refMapped.ref() {
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// At this moment it is guaranteed that the entry is in
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// the map and will not be removed.
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return oldRec
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}
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// This loaded entry is marked as unmapped (so Collect will remove
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// it from the map immediately), try again - this is a busy waiting
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// strategy to wait until Collect() removes this entry from the map.
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//
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// This can be improved by having a list of "Unmapped" entries for
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// one time only usages, OR we can make this a blocking path and use
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// a Mutex that protects the delete operation (delete only if the old
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// record is associated with the key).
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// Let collector get work done to remove the entry from the map.
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runtime.Gosched()
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continue
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}
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// The new entry was added to the map, good to go.
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return rec
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}
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}
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// The order of the input array `kvs` may be sorted after the function is called.
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func (s *syncInstrument) Bind(kvs []attribute.KeyValue) metric.BoundSyncImpl {
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return s.acquireHandle(kvs, nil)
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}
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// The order of the input array `kvs` may be sorted after the function is called.
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func (s *syncInstrument) RecordOne(ctx context.Context, num number.Number, kvs []attribute.KeyValue) {
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h := s.acquireHandle(kvs, nil)
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defer h.Unbind()
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h.RecordOne(ctx, num)
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}
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// NewAccumulator constructs a new Accumulator for the given
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// processor. This Accumulator supports only a single processor.
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//
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// The Accumulator does not start any background process to collect itself
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// periodically, this responsibility lies with the processor, typically,
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// depending on the type of export. For example, a pull-based
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// processor will call Collect() when it receives a request to scrape
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// current metric values. A push-based processor should configure its
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// own periodic collection.
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func NewAccumulator(processor export.Processor, resource *resource.Resource) *Accumulator {
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return &Accumulator{
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processor: processor,
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asyncInstruments: internal.NewAsyncInstrumentState(),
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resource: resource,
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}
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}
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// NewSyncInstrument implements metric.MetricImpl.
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func (m *Accumulator) NewSyncInstrument(descriptor metric.Descriptor) (metric.SyncImpl, error) {
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return &syncInstrument{
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instrument: instrument{
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descriptor: descriptor,
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meter: m,
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},
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}, nil
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}
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// NewAsyncInstrument implements metric.MetricImpl.
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func (m *Accumulator) NewAsyncInstrument(descriptor metric.Descriptor, runner metric.AsyncRunner) (metric.AsyncImpl, error) {
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a := &asyncInstrument{
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instrument: instrument{
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descriptor: descriptor,
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meter: m,
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},
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}
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m.asyncLock.Lock()
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defer m.asyncLock.Unlock()
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m.asyncInstruments.Register(a, runner)
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return a, nil
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}
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// Collect traverses the list of active records and observers and
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// exports data for each active instrument. Collect() may not be
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// called concurrently.
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//
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// During the collection pass, the export.Processor will receive
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// one Export() call per current aggregation.
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//
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// Returns the number of records that were checkpointed.
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func (m *Accumulator) Collect(ctx context.Context) int {
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m.collectLock.Lock()
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defer m.collectLock.Unlock()
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checkpointed := m.observeAsyncInstruments(ctx)
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checkpointed += m.collectSyncInstruments()
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m.currentEpoch++
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return checkpointed
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}
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func (m *Accumulator) collectSyncInstruments() int {
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checkpointed := 0
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m.current.Range(func(key interface{}, value interface{}) bool {
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// Note: always continue to iterate over the entire
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// map by returning `true` in this function.
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inuse := value.(*record)
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mods := atomic.LoadInt64(&inuse.updateCount)
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coll := inuse.collectedCount
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if mods != coll {
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// Updates happened in this interval,
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// checkpoint and continue.
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checkpointed += m.checkpointRecord(inuse)
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inuse.collectedCount = mods
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return true
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}
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// Having no updates since last collection, try to unmap:
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if unmapped := inuse.refMapped.tryUnmap(); !unmapped {
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// The record is referenced by a binding, continue.
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return true
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}
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// If any other goroutines are now trying to re-insert this
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// entry in the map, they are busy calling Gosched() awaiting
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// this deletion:
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m.current.Delete(inuse.mapkey())
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// There's a potential race between `LoadInt64` and
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// `tryUnmap` in this function. Since this is the
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// last we'll see of this record, checkpoint
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mods = atomic.LoadInt64(&inuse.updateCount)
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if mods != coll {
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checkpointed += m.checkpointRecord(inuse)
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}
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return true
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})
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return checkpointed
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}
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// CollectAsync implements internal.AsyncCollector.
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// The order of the input array `kvs` may be sorted after the function is called.
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func (m *Accumulator) CollectAsync(kv []attribute.KeyValue, obs ...metric.Observation) {
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labels := attribute.NewSetWithSortable(kv, &m.asyncSortSlice)
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for _, ob := range obs {
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if a := m.fromAsync(ob.AsyncImpl()); a != nil {
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a.observe(ob.Number(), &labels)
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}
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}
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}
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func (m *Accumulator) observeAsyncInstruments(ctx context.Context) int {
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m.asyncLock.Lock()
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defer m.asyncLock.Unlock()
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asyncCollected := 0
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m.asyncInstruments.Run(ctx, m)
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for _, inst := range m.asyncInstruments.Instruments() {
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if a := m.fromAsync(inst); a != nil {
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asyncCollected += m.checkpointAsync(a)
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}
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}
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return asyncCollected
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}
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func (m *Accumulator) checkpointRecord(r *record) int {
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if r.current == nil {
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return 0
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}
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err := r.current.SynchronizedMove(r.checkpoint, &r.inst.descriptor)
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if err != nil {
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otel.Handle(err)
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return 0
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}
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a := export.NewAccumulation(&r.inst.descriptor, r.labels, m.resource, r.checkpoint)
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err = m.processor.Process(a)
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if err != nil {
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otel.Handle(err)
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}
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return 1
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}
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func (m *Accumulator) checkpointAsync(a *asyncInstrument) int {
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if len(a.recorders) == 0 {
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|
return 0
|
||
|
}
|
||
|
checkpointed := 0
|
||
|
for encodedLabels, lrec := range a.recorders {
|
||
|
lrec := lrec
|
||
|
epochDiff := m.currentEpoch - lrec.observedEpoch
|
||
|
if epochDiff == 0 {
|
||
|
if lrec.observed != nil {
|
||
|
a := export.NewAccumulation(&a.descriptor, lrec.labels, m.resource, lrec.observed)
|
||
|
err := m.processor.Process(a)
|
||
|
if err != nil {
|
||
|
otel.Handle(err)
|
||
|
}
|
||
|
checkpointed++
|
||
|
}
|
||
|
} else if epochDiff > 1 {
|
||
|
// This is second collection cycle with no
|
||
|
// observations for this labelset. Remove the
|
||
|
// recorder.
|
||
|
delete(a.recorders, encodedLabels)
|
||
|
}
|
||
|
}
|
||
|
if len(a.recorders) == 0 {
|
||
|
a.recorders = nil
|
||
|
}
|
||
|
return checkpointed
|
||
|
}
|
||
|
|
||
|
// RecordBatch enters a batch of metric events.
|
||
|
// The order of the input array `kvs` may be sorted after the function is called.
|
||
|
func (m *Accumulator) RecordBatch(ctx context.Context, kvs []attribute.KeyValue, measurements ...metric.Measurement) {
|
||
|
// Labels will be computed the first time acquireHandle is
|
||
|
// called. Subsequent calls to acquireHandle will re-use the
|
||
|
// previously computed value instead of recomputing the
|
||
|
// ordered labels.
|
||
|
var labelsPtr *attribute.Set
|
||
|
for i, meas := range measurements {
|
||
|
s := m.fromSync(meas.SyncImpl())
|
||
|
if s == nil {
|
||
|
continue
|
||
|
}
|
||
|
h := s.acquireHandle(kvs, labelsPtr)
|
||
|
|
||
|
// Re-use labels for the next measurement.
|
||
|
if i == 0 {
|
||
|
labelsPtr = h.labels
|
||
|
}
|
||
|
|
||
|
defer h.Unbind()
|
||
|
h.RecordOne(ctx, meas.Number())
|
||
|
}
|
||
|
}
|
||
|
|
||
|
// RecordOne implements metric.SyncImpl.
|
||
|
func (r *record) RecordOne(ctx context.Context, num number.Number) {
|
||
|
if r.current == nil {
|
||
|
// The instrument is disabled according to the AggregatorSelector.
|
||
|
return
|
||
|
}
|
||
|
if err := aggregator.RangeTest(num, &r.inst.descriptor); err != nil {
|
||
|
otel.Handle(err)
|
||
|
return
|
||
|
}
|
||
|
if err := r.current.Update(ctx, num, &r.inst.descriptor); err != nil {
|
||
|
otel.Handle(err)
|
||
|
return
|
||
|
}
|
||
|
// Record was modified, inform the Collect() that things need
|
||
|
// to be collected while the record is still mapped.
|
||
|
atomic.AddInt64(&r.updateCount, 1)
|
||
|
}
|
||
|
|
||
|
// Unbind implements metric.SyncImpl.
|
||
|
func (r *record) Unbind() {
|
||
|
r.refMapped.unref()
|
||
|
}
|
||
|
|
||
|
func (r *record) mapkey() mapkey {
|
||
|
return mapkey{
|
||
|
descriptor: &r.inst.descriptor,
|
||
|
ordered: r.labels.Equivalent(),
|
||
|
}
|
||
|
}
|
||
|
|
||
|
// fromSync gets a sync implementation object, checking for
|
||
|
// uninitialized instruments and instruments created by another SDK.
|
||
|
func (m *Accumulator) fromSync(sync metric.SyncImpl) *syncInstrument {
|
||
|
if sync != nil {
|
||
|
if inst, ok := sync.Implementation().(*syncInstrument); ok {
|
||
|
return inst
|
||
|
}
|
||
|
}
|
||
|
otel.Handle(ErrUninitializedInstrument)
|
||
|
return nil
|
||
|
}
|
||
|
|
||
|
// fromSync gets an async implementation object, checking for
|
||
|
// uninitialized instruments and instruments created by another SDK.
|
||
|
func (m *Accumulator) fromAsync(async metric.AsyncImpl) *asyncInstrument {
|
||
|
if async != nil {
|
||
|
if inst, ok := async.Implementation().(*asyncInstrument); ok {
|
||
|
return inst
|
||
|
}
|
||
|
}
|
||
|
otel.Handle(ErrUninitializedInstrument)
|
||
|
return nil
|
||
|
}
|