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// Copyright 2022 The OpenZipkin 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 b3
import (
"github.com/openzipkin/zipkin-go/model"
"github.com/openzipkin/zipkin-go/propagation"
)
// Map allows serialization and deserialization of SpanContext into a standard Go map.
type Map map[string]string
// Extract implements Extractor
func (m *Map) Extract() (*model.SpanContext, error) {
var (
traceIDHeader = (*m)[TraceID]
spanIDHeader = (*m)[SpanID]
parentSpanIDHeader = (*m)[ParentSpanID]
sampledHeader = (*m)[Sampled]
flagsHeader = (*m)[Flags]
singleHeader = (*m)[Context]
)
var (
sc *model.SpanContext
sErr error
mErr error
)
if singleHeader != "" {
sc, sErr = ParseSingleHeader(singleHeader)
if sErr == nil {
return sc, nil
}
}
sc, mErr = ParseHeaders(
traceIDHeader, spanIDHeader, parentSpanIDHeader,
sampledHeader, flagsHeader,
)
if mErr != nil && sErr != nil {
return nil, sErr
}
return sc, mErr
}
// Inject implements Injector
func (m *Map) Inject(opts ...InjectOption) propagation.Injector {
options := InjectOptions{shouldInjectMultiHeader: true}
for _, opt := range opts {
opt(&options)
}
return func(sc model.SpanContext) error {
if (model.SpanContext{}) == sc {
return ErrEmptyContext
}
if options.shouldInjectMultiHeader {
if sc.Debug {
(*m)[Flags] = "1"
} else if sc.Sampled != nil {
// Debug is encoded as X-B3-Flags: 1. Since Debug implies Sampled,
// so don't also send "X-B3-Sampled: 1".
if *sc.Sampled {
(*m)[Sampled] = "1"
} else {
(*m)[Sampled] = "0"
}
}
if !sc.TraceID.Empty() && sc.ID > 0 {
(*m)[TraceID] = sc.TraceID.String()
(*m)[SpanID] = sc.ID.String()
if sc.ParentID != nil {
(*m)[ParentSpanID] = sc.ParentID.String()
}
}
}
if options.shouldInjectSingleHeader {
(*m)[Context] = BuildSingleHeader(sc)
}
return nil
}
}
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