vendor/go.opencensus.io/trace/export.go

   1 // Copyright 2017, 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 package trace
  16
  17 import (
  18         "sync"
  19         "sync/atomic"
  20         "time"
  21 )
  22
  23 // Exporter is a type for functions that receive sampled trace spans.
  24 //
  25 // The ExportSpan method should be safe for concurrent use and should return
  26 // quickly; if an Exporter takes a significant amount of time to process a
  27 // SpanData, that work should be done on another goroutine.
  28 //
  29 // The SpanData should not be modified, but a pointer to it can be kept.
  30 type Exporter interface {
  31         ExportSpan(s *SpanData)
  32 }
  33
  34 type exportersMap map[Exporter]struct{}
  35
  36 var (
  37         exporterMu sync.Mutex
  38         exporters  atomic.Value
  39 )
  40
  41 // RegisterExporter adds to the list of Exporters that will receive sampled
  42 // trace spans.
  43 //
  44 // Binaries can register exporters, libraries shouldn't register exporters.
  45 func RegisterExporter(e Exporter) {
  46         exporterMu.Lock()
  47         new := make(exportersMap)
  48         if old, ok := exporters.Load().(exportersMap); ok {
  49                 for k, v := range old {
  50                         new[k] = v
  51                 }
  52         }
  53         new[e] = struct{}{}
  54         exporters.Store(new)
  55         exporterMu.Unlock()
  56 }
  57
  58 // UnregisterExporter removes from the list of Exporters the Exporter that was
  59 // registered with the given name.
  60 func UnregisterExporter(e Exporter) {
  61         exporterMu.Lock()
  62         new := make(exportersMap)
  63         if old, ok := exporters.Load().(exportersMap); ok {
  64                 for k, v := range old {
  65                         new[k] = v
  66                 }
  67         }
  68         delete(new, e)
  69         exporters.Store(new)
  70         exporterMu.Unlock()
  71 }
  72
  73 // SpanData contains all the information collected by a Span.
  74 type SpanData struct {
  75         SpanContext
  76         ParentSpanID SpanID
  77         SpanKind     int
  78         Name         string
  79         StartTime    time.Time
  80         // The wall clock time of EndTime will be adjusted to always be offset
  81         // from StartTime by the duration of the span.
  82         EndTime time.Time
  83         // The values of Attributes each have type string, bool, or int64.
  84         Attributes    map[string]interface{}
  85         Annotations   []Annotation
  86         MessageEvents []MessageEvent
  87         Status
  88         Links           []Link
  89         HasRemoteParent bool
  90 }