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// Copyright The OpenTelemetry Authors
// SPDX-License-Identifier: Apache-2.0
package global // import "go.opentelemetry.io/otel/internal/global"
import (
"errors"
"sync"
"sync/atomic"
"go.opentelemetry.io/otel/metric"
"go.opentelemetry.io/otel/propagation"
"go.opentelemetry.io/otel/trace"
)
type (
errorHandlerHolder struct {
eh ErrorHandler
}
tracerProviderHolder struct {
tp trace.TracerProvider
}
propagatorsHolder struct {
tm propagation.TextMapPropagator
}
meterProviderHolder struct {
mp metric.MeterProvider
}
)
var (
globalErrorHandler = defaultErrorHandler()
globalTracer = defaultTracerValue()
globalPropagators = defaultPropagatorsValue()
globalMeterProvider = defaultMeterProvider()
delegateErrorHandlerOnce sync.Once
delegateTraceOnce sync.Once
delegateTextMapPropagatorOnce sync.Once
delegateMeterOnce sync.Once
)
// GetErrorHandler returns the global ErrorHandler instance.
//
// The default ErrorHandler instance returned will log all errors to STDERR
// until an override ErrorHandler is set with SetErrorHandler. All
// ErrorHandler returned prior to this will automatically forward errors to
// the set instance instead of logging.
//
// Subsequent calls to SetErrorHandler after the first will not forward errors
// to the new ErrorHandler for prior returned instances.
func GetErrorHandler() ErrorHandler {
return globalErrorHandler.Load().(errorHandlerHolder).eh
}
// SetErrorHandler sets the global ErrorHandler to h.
//
// The first time this is called all ErrorHandler previously returned from
// GetErrorHandler will send errors to h instead of the default logging
// ErrorHandler. Subsequent calls will set the global ErrorHandler, but not
// delegate errors to h.
func SetErrorHandler(h ErrorHandler) {
current := GetErrorHandler()
if _, cOk := current.(*ErrDelegator); cOk {
if _, ehOk := h.(*ErrDelegator); ehOk && current == h {
// Do not assign to the delegate of the default ErrDelegator to be
// itself.
Error(
errors.New("no ErrorHandler delegate configured"),
"ErrorHandler remains its current value.",
)
return
}
}
delegateErrorHandlerOnce.Do(func() {
if def, ok := current.(*ErrDelegator); ok {
def.setDelegate(h)
}
})
globalErrorHandler.Store(errorHandlerHolder{eh: h})
}
// 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 its 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 its 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})
}
// MeterProvider is the internal implementation for global.MeterProvider.
func MeterProvider() metric.MeterProvider {
return globalMeterProvider.Load().(meterProviderHolder).mp
}
// SetMeterProvider is the internal implementation for global.SetMeterProvider.
func SetMeterProvider(mp metric.MeterProvider) {
current := MeterProvider()
if _, cOk := current.(*meterProvider); cOk {
if _, mpOk := mp.(*meterProvider); mpOk && current == mp {
// Do not assign the default delegating MeterProvider to delegate
// to itself.
Error(
errors.New("no delegate configured in meter provider"),
"Setting meter provider to its current value. No delegate will be configured",
)
return
}
}
delegateMeterOnce.Do(func() {
if def, ok := current.(*meterProvider); ok {
def.setDelegate(mp)
}
})
globalMeterProvider.Store(meterProviderHolder{mp: mp})
}
func defaultErrorHandler() *atomic.Value {
v := &atomic.Value{}
v.Store(errorHandlerHolder{eh: &ErrDelegator{}})
return v
}
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
}
func defaultMeterProvider() *atomic.Value {
v := &atomic.Value{}
v.Store(meterProviderHolder{mp: &meterProvider{}})
return v
}
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