restic/vendor/go.opencensus.io/trace/exemplar.go

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2019-01-27 20:07:57 +00:00
// 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
}