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// Copyright 2018, OpenCensus 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 stats
import (
"context"
"go.opencensus.io/metric/metricdata"
"go.opencensus.io/stats/internal"
"go.opencensus.io/tag"
)
func init() {
internal.SubscriptionReporter = func(measure string) {
mu.Lock()
measures[measure].subscribe()
mu.Unlock()
}
}
// Recorder provides an interface for exporting measurement information from
// the static Record method by using the WithRecorder option.
type Recorder interface {
// Record records a set of measurements associated with the given tags and attachments.
// The second argument is a `[]Measurement`.
Record(*tag.Map, interface{}, map[string]interface{})
}
type recordOptions struct {
attachments metricdata.Attachments
mutators []tag.Mutator
measurements []Measurement
recorder Recorder
}
// WithAttachments applies provided exemplar attachments.
func WithAttachments(attachments metricdata.Attachments) Options {
return func(ro *recordOptions) {
ro.attachments = attachments
}
}
// WithTags applies provided tag mutators.
func WithTags(mutators ...tag.Mutator) Options {
return func(ro *recordOptions) {
ro.mutators = mutators
}
}
// WithMeasurements applies provided measurements.
func WithMeasurements(measurements ...Measurement) Options {
return func(ro *recordOptions) {
ro.measurements = measurements
}
}
// WithRecorder records the measurements to the specified `Recorder`, rather
// than to the global metrics recorder.
func WithRecorder(meter Recorder) Options {
return func(ro *recordOptions) {
ro.recorder = meter
}
}
// Options apply changes to recordOptions.
type Options func(*recordOptions)
func createRecordOption(ros ...Options) *recordOptions {
o := &recordOptions{}
for _, ro := range ros {
ro(o)
}
return o
}
type measurementRecorder = func(tags *tag.Map, measurement []Measurement, attachments map[string]interface{})
// Record records one or multiple measurements with the same context at once.
// If there are any tags in the context, measurements will be tagged with them.
func Record(ctx context.Context, ms ...Measurement) {
// Record behaves the same as RecordWithOptions, but because we do not have to handle generic functionality
// (RecordOptions) we can reduce some allocations to speed up this hot path
if len(ms) == 0 {
return
}
recorder := internal.MeasurementRecorder.(measurementRecorder)
record := false
for _, m := range ms {
if m.desc.subscribed() {
record = true
break
}
}
if !record {
return
}
recorder(tag.FromContext(ctx), ms, nil)
return
}
// RecordWithTags records one or multiple measurements at once.
//
// Measurements will be tagged with the tags in the context mutated by the mutators.
// RecordWithTags is useful if you want to record with tag mutations but don't want
// to propagate the mutations in the context.
func RecordWithTags(ctx context.Context, mutators []tag.Mutator, ms ...Measurement) error {
return RecordWithOptions(ctx, WithTags(mutators...), WithMeasurements(ms...))
}
// RecordWithOptions records measurements from the given options (if any) against context
// and tags and attachments in the options (if any).
// If there are any tags in the context, measurements will be tagged with them.
func RecordWithOptions(ctx context.Context, ros ...Options) error {
o := createRecordOption(ros...)
if len(o.measurements) == 0 {
return nil
}
recorder := internal.DefaultRecorder
if o.recorder != nil {
recorder = o.recorder.Record
}
if recorder == nil {
return nil
}
record := false
for _, m := range o.measurements {
if m.desc.subscribed() {
record = true
break
}
}
if !record {
return nil
}
if len(o.mutators) > 0 {
var err error
if ctx, err = tag.New(ctx, o.mutators...); err != nil {
return err
}
}
recorder(tag.FromContext(ctx), o.measurements, o.attachments)
return nil
}