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// Copyright 2017, 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 trace
import (
"sync"
"sync/atomic"
"time"
)
// Exporter is a type for functions that receive sampled trace spans.
//
// The ExportSpan method should be safe for concurrent use and should return
// quickly; if an Exporter takes a significant amount of time to process a
// SpanData, that work should be done on another goroutine.
//
// The SpanData should not be modified, but a pointer to it can be kept.
type Exporter interface {
ExportSpan(s *SpanData)
}
type exportersMap map[Exporter]struct{}
var (
exporterMu sync.Mutex
exporters atomic.Value
)
// RegisterExporter adds to the list of Exporters that will receive sampled
// trace spans.
//
// Binaries can register exporters, libraries shouldn't register exporters.
func RegisterExporter(e Exporter) {
exporterMu.Lock()
new := make(exportersMap)
if old, ok := exporters.Load().(exportersMap); ok {
for k, v := range old {
new[k] = v
}
}
new[e] = struct{}{}
exporters.Store(new)
exporterMu.Unlock()
}
// UnregisterExporter removes from the list of Exporters the Exporter that was
// registered with the given name.
func UnregisterExporter(e Exporter) {
exporterMu.Lock()
new := make(exportersMap)
if old, ok := exporters.Load().(exportersMap); ok {
for k, v := range old {
new[k] = v
}
}
delete(new, e)
exporters.Store(new)
exporterMu.Unlock()
}
// SpanData contains all the information collected by a Span.
type SpanData struct {
SpanContext
ParentSpanID SpanID
SpanKind int
Name string
StartTime time.Time
// The wall clock time of EndTime will be adjusted to always be offset
// from StartTime by the duration of the span.
EndTime time.Time
// The values of Attributes each have type string, bool, or int64.
Attributes map[string]interface{}
Annotations []Annotation
MessageEvents []MessageEvent
Status
Links []Link
HasRemoteParent bool
DroppedAttributeCount int
DroppedAnnotationCount int
DroppedMessageEventCount int
DroppedLinkCount int
// ChildSpanCount holds the number of child span created for this span.
ChildSpanCount int
}