59 lines
1.7 KiB
Go
59 lines
1.7 KiB
Go
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// Copyright The OpenTelemetry Authors
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package propagation // import "go.opentelemetry.io/otel/propagation"
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import (
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"context"
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"go.opentelemetry.io/otel/baggage"
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)
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const baggageHeader = "baggage"
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// Baggage is a propagator that supports the W3C Baggage format.
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//
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// This propagates user-defined baggage associated with a trace. The complete
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// specification is defined at https://www.w3.org/TR/baggage/.
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type Baggage struct{}
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var _ TextMapPropagator = Baggage{}
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// Inject sets baggage key-values from ctx into the carrier.
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func (b Baggage) Inject(ctx context.Context, carrier TextMapCarrier) {
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bStr := baggage.FromContext(ctx).String()
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if bStr != "" {
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carrier.Set(baggageHeader, bStr)
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}
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}
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// Extract returns a copy of parent with the baggage from the carrier added.
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func (b Baggage) Extract(parent context.Context, carrier TextMapCarrier) context.Context {
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bStr := carrier.Get(baggageHeader)
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if bStr == "" {
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return parent
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}
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bag, err := baggage.Parse(bStr)
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if err != nil {
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return parent
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}
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return baggage.ContextWithBaggage(parent, bag)
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}
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// Fields returns the keys who's values are set with Inject.
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func (b Baggage) Fields() []string {
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return []string{baggageHeader}
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}
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