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mirror of https://github.com/open-telemetry/opentelemetry-go.git synced 2024-12-14 10:13:10 +02:00
opentelemetry-go/api/global/internal/state.go
Tyler Yahn a485d0ec64
Update License header for all source files (#586)
* Update License header for all source files

- Add Apache 2.0 header to source files that did not have one.
- Update all existing headers dated to 2019 to be 2020
- Remove comma from License header to comply with the Apache 2.0
  guidelines.

* Update Copyright notice

Use the standard Copyright notices outlined by the
[CNCF](https://github.com/cncf/foundation/blob/master/copyright-notices.md#copyright-notices)
2020-03-23 22:41:10 -07:00

141 lines
4.0 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 internal
import (
"sync"
"sync/atomic"
"go.opentelemetry.io/otel/api/correlation"
"go.opentelemetry.io/otel/api/metric"
"go.opentelemetry.io/otel/api/propagation"
"go.opentelemetry.io/otel/api/trace"
)
type (
traceProviderHolder struct {
tp trace.Provider
}
meterProviderHolder struct {
mp metric.Provider
}
propagatorsHolder struct {
pr propagation.Propagators
}
)
var (
globalTracer = defaultTracerValue()
globalMeter = defaultMeterValue()
globalPropagators = defaultPropagatorsValue()
delegateMeterOnce sync.Once
delegateTraceOnce sync.Once
)
// TraceProvider is the internal implementation for global.TraceProvider.
func TraceProvider() trace.Provider {
return globalTracer.Load().(traceProviderHolder).tp
}
// SetTraceProvider is the internal implementation for global.SetTraceProvider.
func SetTraceProvider(tp trace.Provider) {
delegateTraceOnce.Do(func() {
current := TraceProvider()
if current == tp {
// Setting the provider to the prior default is nonsense, panic.
// Panic is acceptable because we are likely still early in the
// process lifetime.
panic("invalid Provider, the global instance cannot be reinstalled")
} else if def, ok := current.(*traceProvider); ok {
def.setDelegate(tp)
}
})
globalTracer.Store(traceProviderHolder{tp: tp})
}
// MeterProvider is the internal implementation for global.MeterProvider.
func MeterProvider() metric.Provider {
return globalMeter.Load().(meterProviderHolder).mp
}
// SetMeterProvider is the internal implementation for global.SetMeterProvider.
func SetMeterProvider(mp metric.Provider) {
delegateMeterOnce.Do(func() {
current := MeterProvider()
if current == mp {
// Setting the provider to the prior default is nonsense, panic.
// Panic is acceptable because we are likely still early in the
// process lifetime.
panic("invalid Provider, the global instance cannot be reinstalled")
} else if def, ok := current.(*meterProvider); ok {
def.setDelegate(mp)
}
})
globalMeter.Store(meterProviderHolder{mp: mp})
}
// Propagators is the internal implementation for global.Propagators.
func Propagators() propagation.Propagators {
return globalPropagators.Load().(propagatorsHolder).pr
}
// SetPropagators is the internal implementation for global.SetPropagators.
func SetPropagators(pr propagation.Propagators) {
globalPropagators.Store(propagatorsHolder{pr: pr})
}
func defaultTracerValue() *atomic.Value {
v := &atomic.Value{}
v.Store(traceProviderHolder{tp: &traceProvider{}})
return v
}
func defaultMeterValue() *atomic.Value {
v := &atomic.Value{}
v.Store(meterProviderHolder{mp: &meterProvider{}})
return v
}
func defaultPropagatorsValue() *atomic.Value {
v := &atomic.Value{}
v.Store(propagatorsHolder{pr: getDefaultPropagators()})
return v
}
// getDefaultPropagators returns a default Propagators, configured
// with W3C trace and correlation context propagation.
func getDefaultPropagators() propagation.Propagators {
tcPropagator := trace.TraceContext{}
ccPropagator := correlation.CorrelationContext{}
return propagation.New(
propagation.WithExtractors(tcPropagator, ccPropagator),
propagation.WithInjectors(tcPropagator, ccPropagator),
)
}
// ResetForTest restores the initial global state, for testing purposes.
func ResetForTest() {
globalTracer = defaultTracerValue()
globalMeter = defaultMeterValue()
globalPropagators = defaultPropagatorsValue()
delegateMeterOnce = sync.Once{}
delegateTraceOnce = sync.Once{}
}