cloudflared-mirror/vendor/go.opentelemetry.io/otel/internal/global/state.go

128 lines
3.6 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 (
"errors"
"sync"
"sync/atomic"
"testing"
"go.opentelemetry.io/otel/propagation"
"go.opentelemetry.io/otel/trace"
)
type (
tracerProviderHolder struct {
tp trace.TracerProvider
}
propagatorsHolder struct {
tm propagation.TextMapPropagator
}
)
var (
globalTracer = defaultTracerValue()
globalPropagators = defaultPropagatorsValue()
delegateTraceOnce sync.Once
delegateTextMapPropagatorOnce sync.Once
)
// TracerProvider is the internal implementation for global.TracerProvider.
func TracerProvider() trace.TracerProvider {
return globalTracer.Load().(tracerProviderHolder).tp
}
// SetTracerProvider is the internal implementation for global.SetTracerProvider.
func SetTracerProvider(tp trace.TracerProvider) {
current := TracerProvider()
if _, cOk := current.(*tracerProvider); cOk {
if _, tpOk := tp.(*tracerProvider); tpOk && current == tp {
// Do not assign the default delegating TracerProvider to delegate
// to itself.
Error(
errors.New("no delegate configured in tracer provider"),
"Setting tracer provider to it's current value. No delegate will be configured",
)
return
}
}
delegateTraceOnce.Do(func() {
if def, ok := current.(*tracerProvider); ok {
def.setDelegate(tp)
}
})
globalTracer.Store(tracerProviderHolder{tp: tp})
}
// TextMapPropagator is the internal implementation for global.TextMapPropagator.
func TextMapPropagator() propagation.TextMapPropagator {
return globalPropagators.Load().(propagatorsHolder).tm
}
// SetTextMapPropagator is the internal implementation for global.SetTextMapPropagator.
func SetTextMapPropagator(p propagation.TextMapPropagator) {
current := TextMapPropagator()
if _, cOk := current.(*textMapPropagator); cOk {
if _, pOk := p.(*textMapPropagator); pOk && current == p {
// Do not assign the default delegating TextMapPropagator to
// delegate to itself.
Error(
errors.New("no delegate configured in text map propagator"),
"Setting text map propagator to it's current value. No delegate will be configured",
)
return
}
}
// For the textMapPropagator already returned by TextMapPropagator
// delegate to p.
delegateTextMapPropagatorOnce.Do(func() {
if def, ok := current.(*textMapPropagator); ok {
def.SetDelegate(p)
}
})
// Return p when subsequent calls to TextMapPropagator are made.
globalPropagators.Store(propagatorsHolder{tm: p})
}
func defaultTracerValue() *atomic.Value {
v := &atomic.Value{}
v.Store(tracerProviderHolder{tp: &tracerProvider{}})
return v
}
func defaultPropagatorsValue() *atomic.Value {
v := &atomic.Value{}
v.Store(propagatorsHolder{tm: newTextMapPropagator()})
return v
}
// ResetForTest configures the test to restores the initial global state during
// its Cleanup step
func ResetForTest(t testing.TB) {
t.Cleanup(func() {
globalTracer = defaultTracerValue()
globalPropagators = defaultPropagatorsValue()
delegateTraceOnce = sync.Once{}
delegateTextMapPropagatorOnce = sync.Once{}
})
}