mirror of https://github.com/docker/cli.git
97 lines
3.0 KiB
Go
97 lines
3.0 KiB
Go
// Copyright The OpenTelemetry Authors
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package otel // import "go.opentelemetry.io/otel"
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import (
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"log"
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"os"
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"sync/atomic"
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"unsafe"
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)
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var (
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// globalErrorHandler provides an ErrorHandler that can be used
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// throughout an OpenTelemetry instrumented project. When a user
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// specified ErrorHandler is registered (`SetErrorHandler`) all calls to
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// `Handle` and will be delegated to the registered ErrorHandler.
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globalErrorHandler = defaultErrorHandler()
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// Compile-time check that delegator implements ErrorHandler.
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_ ErrorHandler = (*delegator)(nil)
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// Compile-time check that errLogger implements ErrorHandler.
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_ ErrorHandler = (*errLogger)(nil)
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)
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type delegator struct {
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delegate unsafe.Pointer
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}
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func (d *delegator) Handle(err error) {
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d.getDelegate().Handle(err)
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}
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func (d *delegator) getDelegate() ErrorHandler {
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return *(*ErrorHandler)(atomic.LoadPointer(&d.delegate))
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}
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// setDelegate sets the ErrorHandler delegate.
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func (d *delegator) setDelegate(eh ErrorHandler) {
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atomic.StorePointer(&d.delegate, unsafe.Pointer(&eh))
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}
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func defaultErrorHandler() *delegator {
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d := &delegator{}
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d.setDelegate(&errLogger{l: log.New(os.Stderr, "", log.LstdFlags)})
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return d
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}
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// errLogger logs errors if no delegate is set, otherwise they are delegated.
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type errLogger struct {
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l *log.Logger
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}
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// Handle logs err if no delegate is set, otherwise it is delegated.
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func (h *errLogger) Handle(err error) {
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h.l.Print(err)
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}
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// GetErrorHandler returns the global ErrorHandler instance.
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//
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// The default ErrorHandler instance returned will log all errors to STDERR
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// until an override ErrorHandler is set with SetErrorHandler. All
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// ErrorHandler returned prior to this will automatically forward errors to
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// the set instance instead of logging.
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//
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// Subsequent calls to SetErrorHandler after the first will not forward errors
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// to the new ErrorHandler for prior returned instances.
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func GetErrorHandler() ErrorHandler {
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return globalErrorHandler
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}
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// SetErrorHandler sets the global ErrorHandler to h.
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//
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// The first time this is called all ErrorHandler previously returned from
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// GetErrorHandler will send errors to h instead of the default logging
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// ErrorHandler. Subsequent calls will set the global ErrorHandler, but not
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// delegate errors to h.
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func SetErrorHandler(h ErrorHandler) {
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globalErrorHandler.setDelegate(h)
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}
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// Handle is a convenience function for ErrorHandler().Handle(err).
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func Handle(err error) {
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GetErrorHandler().Handle(err)
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}
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