// 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/global" import ( "log" "os" "sync" "sync/atomic" "go.opentelemetry.io/otel" ) var ( // globalErrorHandler provides an ErrorHandler that can be used // throughout an OpenTelemetry instrumented project. When a user // specified ErrorHandler is registered (`SetErrorHandler`) all calls to // `Handle` and will be delegated to the registered ErrorHandler. globalErrorHandler = &loggingErrorHandler{ l: log.New(os.Stderr, "", log.LstdFlags), } // delegateErrorHandlerOnce ensures that a user provided ErrorHandler is // only ever registered once. delegateErrorHandlerOnce sync.Once // Comiple time check that loggingErrorHandler implements ErrorHandler. _ otel.ErrorHandler = (*loggingErrorHandler)(nil) ) // loggingErrorHandler logs all errors to STDERR. type loggingErrorHandler struct { delegate atomic.Value l *log.Logger } // setDelegate sets the ErrorHandler delegate if one is not already set. func (h *loggingErrorHandler) setDelegate(d otel.ErrorHandler) { if h.delegate.Load() != nil { // Delegate already registered return } h.delegate.Store(d) } // Handle implements otel.ErrorHandler. func (h *loggingErrorHandler) Handle(err error) { if d := h.delegate.Load(); d != nil { d.(otel.ErrorHandler).Handle(err) return } h.l.Print(err) } // ErrorHandler returns the global ErrorHandler instance. If no ErrorHandler // instance has been set (`SetErrorHandler`), the default ErrorHandler which // logs errors to STDERR is returned. func ErrorHandler() otel.ErrorHandler { return globalErrorHandler } // SetErrorHandler sets the global ErrorHandler to be h. func SetErrorHandler(h otel.ErrorHandler) { delegateErrorHandlerOnce.Do(func() { current := ErrorHandler() if current == h { return } if internalHandler, ok := current.(*loggingErrorHandler); ok { internalHandler.setDelegate(h) } }) } // Handle is a convience function for ErrorHandler().Handle(err) func Handle(err error) { ErrorHandler().Handle(err) }