vendor/go.opencensus.io/stats/record.go

   1 // Copyright 2018, OpenCensus Authors
   2 //
   3 // Licensed under the Apache License, Version 2.0 (the "License");
   4 // you may not use this file except in compliance with the License.
   5 // You may obtain a copy of the License at
   6 //
   7 //     http://www.apache.org/licenses/LICENSE-2.0
   8 //
   9 // Unless required by applicable law or agreed to in writing, software
  10 // distributed under the License is distributed on an "AS IS" BASIS,
  11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  12 // See the License for the specific language governing permissions and
  13 // limitations under the License.
  14 //
  15
  16 package stats
  17
  18 import (
  19         "context"
  20
  21         "go.opencensus.io/exemplar"
  22         "go.opencensus.io/stats/internal"
  23         "go.opencensus.io/tag"
  24 )
  25
  26 func init() {
  27         internal.SubscriptionReporter = func(measure string) {
  28                 mu.Lock()
  29                 measures[measure].subscribe()
  30                 mu.Unlock()
  31         }
  32 }
  33
  34 // Record records one or multiple measurements with the same context at once.
  35 // If there are any tags in the context, measurements will be tagged with them.
  36 func Record(ctx context.Context, ms ...Measurement) {
  37         recorder := internal.DefaultRecorder
  38         if recorder == nil {
  39                 return
  40         }
  41         if len(ms) == 0 {
  42                 return
  43         }
  44         record := false
  45         for _, m := range ms {
  46                 if m.m.subscribed() {
  47                         record = true
  48                         break
  49                 }
  50         }
  51         if !record {
  52                 return
  53         }
  54         recorder(tag.FromContext(ctx), ms, exemplar.AttachmentsFromContext(ctx))
  55 }
  56
  57 // RecordWithTags records one or multiple measurements at once.
  58 //
  59 // Measurements will be tagged with the tags in the context mutated by the mutators.
  60 // RecordWithTags is useful if you want to record with tag mutations but don't want
  61 // to propagate the mutations in the context.
  62 func RecordWithTags(ctx context.Context, mutators []tag.Mutator, ms ...Measurement) error {
  63         ctx, err := tag.New(ctx, mutators...)
  64         if err != nil {
  65                 return err
  66         }
  67         Record(ctx, ms...)
  68         return nil
  69 }