mirror of
https://github.com/open-telemetry/opentelemetry-go.git
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ab164e6638
* Merge propagation Rename and merge propagation and api/propagation to api/propagators. Drop propagator suffix in general such that TextFormatPropagator becomes TextFormat since usage is propagators.TextFormat fixes #311 * Rebase and godoc updates * Revert go mod changes * Replace carrier with supplier in godoc
81 lines
2.2 KiB
Go
81 lines
2.2 KiB
Go
// Copyright 2019, 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 propagators
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import (
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"go.opentelemetry.io/otel/api/core"
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)
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// BinaryFormat is an interface that specifies methods to convert SpanContext
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// to/from byte array.
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type BinaryFormat interface {
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// ToBytes serializes span context into a byte array and returns the array.
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ToBytes(sc core.SpanContext) []byte
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// FromBytes de-serializes byte array into span context and returns the span context.
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FromBytes([]byte) core.SpanContext
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}
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var _ BinaryFormat = binary{}
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type binary struct{}
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// Binary creates a new propagator. The propagator implements
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// ToBytes and FromBytes method to transform SpanContext to/from byte array.
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func Binary() BinaryFormat {
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return binary{}
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}
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// ToBytes implements ToBytes method of propagators.BinaryFormat.
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// It serializes core.SpanContext into a byte array.
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func (bp binary) ToBytes(sc core.SpanContext) []byte {
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if sc == core.EmptySpanContext() {
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return nil
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}
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var b [29]byte
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copy(b[2:18], sc.TraceID[:])
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b[18] = 1
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copy(b[19:27], sc.SpanID[:])
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b[27] = 2
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b[28] = sc.TraceFlags
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return b[:]
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}
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// FromBytes implements FromBytes method of propagators.BinaryFormat.
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// It de-serializes bytes into core.SpanContext.
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func (bp binary) FromBytes(b []byte) (sc core.SpanContext) {
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if len(b) == 0 {
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return core.EmptySpanContext()
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}
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b = b[1:]
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if len(b) >= 17 && b[0] == 0 {
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copy(sc.TraceID[:], b[1:17])
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b = b[17:]
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} else {
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return core.EmptySpanContext()
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}
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if len(b) >= 9 && b[0] == 1 {
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copy(sc.SpanID[:], b[1:9])
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b = b[9:]
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}
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if len(b) >= 2 && b[0] == 2 {
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sc.TraceFlags = b[1]
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}
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if sc.IsValid() {
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return sc
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}
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return core.EmptySpanContext()
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}
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