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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 trace
-
- import (
- "context"
- "encoding/hex"
-
- "go.opencensus.io/exemplar"
- )
-
- func init() {
- exemplar.RegisterAttachmentExtractor(attachSpanContext)
- }
-
- func attachSpanContext(ctx context.Context, a exemplar.Attachments) exemplar.Attachments {
- span := FromContext(ctx)
- if span == nil {
- return a
- }
- sc := span.SpanContext()
- if !sc.IsSampled() {
- return a
- }
- if a == nil {
- a = make(exemplar.Attachments)
- }
- a[exemplar.KeyTraceID] = hex.EncodeToString(sc.TraceID[:])
- a[exemplar.KeySpanID] = hex.EncodeToString(sc.SpanID[:])
- return a
- }
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