mirror of
https://github.com/superseriousbusiness/gotosocial.git
synced 2024-11-23 20:26:39 +00:00
83 lines
2.7 KiB
Go
83 lines
2.7 KiB
Go
|
// 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 global // import "go.opentelemetry.io/otel/internal/global"
|
||
|
|
|
||
|
|
import (
|
||
|
|
"context"
|
||
|
|
"sync"
|
||
|
|
|
||
|
|
"go.opentelemetry.io/otel/propagation"
|
||
|
|
)
|
||
|
|
|
||
|
|
// textMapPropagator is a default TextMapPropagator that delegates calls to a
|
||
|
|
// registered delegate if one is set, otherwise it defaults to delegating the
|
||
|
|
// calls to a the default no-op propagation.TextMapPropagator.
|
||
|
|
type textMapPropagator struct {
|
||
|
|
mtx sync.Mutex
|
||
|
|
once sync.Once
|
||
|
|
delegate propagation.TextMapPropagator
|
||
|
|
noop propagation.TextMapPropagator
|
||
|
|
}
|
||
|
|
|
||
|
|
// Compile-time guarantee that textMapPropagator implements the
|
||
|
|
// propagation.TextMapPropagator interface.
|
||
|
|
var _ propagation.TextMapPropagator = (*textMapPropagator)(nil)
|
||
|
|
|
||
|
|
func newTextMapPropagator() *textMapPropagator {
|
||
|
|
return &textMapPropagator{
|
||
|
|
noop: propagation.NewCompositeTextMapPropagator(),
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
// SetDelegate sets a delegate propagation.TextMapPropagator that all calls are
|
||
|
|
// forwarded to. Delegation can only be performed once, all subsequent calls
|
||
|
|
// perform no delegation.
|
||
|
|
func (p *textMapPropagator) SetDelegate(delegate propagation.TextMapPropagator) {
|
||
|
|
if delegate == nil {
|
||
|
|
return
|
||
|
|
}
|
||
|
|
|
||
|
|
p.mtx.Lock()
|
||
|
|
p.once.Do(func() { p.delegate = delegate })
|
||
|
|
p.mtx.Unlock()
|
||
|
|
}
|
||
|
|
|
||
|
|
// effectiveDelegate returns the current delegate of p if one is set,
|
||
|
|
// otherwise the default noop TextMapPropagator is returned. This method
|
||
|
|
// can be called concurrently.
|
||
|
|
func (p *textMapPropagator) effectiveDelegate() propagation.TextMapPropagator {
|
||
|
|
p.mtx.Lock()
|
||
|
|
defer p.mtx.Unlock()
|
||
|
|
if p.delegate != nil {
|
||
|
|
return p.delegate
|
||
|
|
}
|
||
|
|
return p.noop
|
||
|
|
}
|
||
|
|
|
||
|
|
// Inject set cross-cutting concerns from the Context into the carrier.
|
||
|
|
func (p *textMapPropagator) Inject(ctx context.Context, carrier propagation.TextMapCarrier) {
|
||
|
|
p.effectiveDelegate().Inject(ctx, carrier)
|
||
|
|
}
|
||
|
|
|
||
|
|
// Extract reads cross-cutting concerns from the carrier into a Context.
|
||
|
|
func (p *textMapPropagator) Extract(ctx context.Context, carrier propagation.TextMapCarrier) context.Context {
|
||
|
|
return p.effectiveDelegate().Extract(ctx, carrier)
|
||
|
|
}
|
||
|
|
|
||
|
|
// Fields returns the keys whose values are set with Inject.
|
||
|
|
func (p *textMapPropagator) Fields() []string {
|
||
|
|
return p.effectiveDelegate().Fields()
|
||
|
|
}
|