Golang Context.Value示例

示例#1

文件： context.go 项目： rht/bssim

// LogError logs the error to the owner of the context.
//
// If this context was created with ContextWithErrorLog, then this method
// passes the error to context creator over an unbuffered channel.
//
// If this context was created by other means, this method is a no-op.
func LogError(ctx context.Context, err error) {
	v := ctx.Value(errLogKey)
	errs, ok := v.(privateChanType)
	if !ok {
		return
	}
	errs <- err
}

示例#2

文件： context.go 项目： rht/bssim

func MetadataFromContext(ctx context.Context) (Metadata, error) {
	value := ctx.Value(metadataKey)
	if value != nil {
		metadata, ok := value.(Metadata)
		if ok {
			return metadata, nil
		}
	}
	return nil, errors.New("context contains no metadata")
}

示例#3

文件： query.go 项目： rht/bssim

func PublishQueryEvent(ctx context.Context, ev *QueryEvent) {
	ich := ctx.Value(RoutingQueryKey)
	if ich == nil {
		return
	}

	ch, ok := ich.(chan<- *QueryEvent)
	if !ok {
		return
	}

	select {
	case ch <- ev:
	case <-ctx.Done():
	}
}