forgejo-federation/vendor/go.opentelemetry.io/otel/propagation/baggage.go

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// Copyright The OpenTelemetry 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 propagation // import "go.opentelemetry.io/otel/propagation"
import (
"context"
"net/url"
"strings"
"go.opentelemetry.io/otel/attribute"
"go.opentelemetry.io/otel/internal/baggage"
)
const baggageHeader = "baggage"
// Baggage is a propagator that supports the W3C Baggage format.
//
// This propagates user-defined baggage associated with a trace. The complete
// specification is defined at https://w3c.github.io/baggage/.
type Baggage struct{}
var _ TextMapPropagator = Baggage{}
// Inject sets baggage key-values from ctx into the carrier.
func (b Baggage) Inject(ctx context.Context, carrier TextMapCarrier) {
baggageMap := baggage.MapFromContext(ctx)
firstIter := true
var headerValueBuilder strings.Builder
baggageMap.Foreach(func(kv attribute.KeyValue) bool {
if !firstIter {
headerValueBuilder.WriteRune(',')
}
firstIter = false
headerValueBuilder.WriteString(url.QueryEscape(strings.TrimSpace((string)(kv.Key))))
headerValueBuilder.WriteRune('=')
headerValueBuilder.WriteString(url.QueryEscape(strings.TrimSpace(kv.Value.Emit())))
return true
})
if headerValueBuilder.Len() > 0 {
headerString := headerValueBuilder.String()
carrier.Set(baggageHeader, headerString)
}
}
// Extract returns a copy of parent with the baggage from the carrier added.
func (b Baggage) Extract(parent context.Context, carrier TextMapCarrier) context.Context {
bVal := carrier.Get(baggageHeader)
if bVal == "" {
return parent
}
baggageValues := strings.Split(bVal, ",")
keyValues := make([]attribute.KeyValue, 0, len(baggageValues))
for _, baggageValue := range baggageValues {
valueAndProps := strings.Split(baggageValue, ";")
if len(valueAndProps) < 1 {
continue
}
nameValue := strings.Split(valueAndProps[0], "=")
if len(nameValue) < 2 {
continue
}
name, err := url.QueryUnescape(nameValue[0])
if err != nil {
continue
}
trimmedName := strings.TrimSpace(name)
value, err := url.QueryUnescape(nameValue[1])
if err != nil {
continue
}
trimmedValue := strings.TrimSpace(value)
// TODO (skaris): properties defiend https://w3c.github.io/correlation-context/, are currently
// just put as part of the value.
var trimmedValueWithProps strings.Builder
trimmedValueWithProps.WriteString(trimmedValue)
for _, prop := range valueAndProps[1:] {
trimmedValueWithProps.WriteRune(';')
trimmedValueWithProps.WriteString(prop)
}
keyValues = append(keyValues, attribute.String(trimmedName, trimmedValueWithProps.String()))
}
if len(keyValues) > 0 {
// Only update the context if valid values were found
return baggage.ContextWithMap(parent, baggage.NewMap(baggage.MapUpdate{
MultiKV: keyValues,
}))
}
return parent
}
// Fields returns the keys who's values are set with Inject.
func (b Baggage) Fields() []string {
return []string{baggageHeader}
}