sdk-go/v1/binding/buffering/copy_message.go

52 lines
1.7 KiB
Go

package buffering
import (
"context"
"github.com/cloudevents/sdk-go/v1/binding"
)
// BufferMessage does the same than CopyMessage and it also bounds the original Message
// lifecycle to the newly created message: calling Finish() on the returned message calls m.Finish()
func BufferMessage(ctx context.Context, m binding.Message, transformers ...binding.TransformerFactory) (binding.Message, error) {
result, err := CopyMessage(ctx, m, transformers...)
if err != nil {
return nil, err
}
return binding.WithFinish(result, func(err error) { _ = m.Finish(err) }), nil
}
// CopyMessage reads m once and creates an in-memory copy depending on the encoding of m.
// The returned copy is not dependent on any transport and can be read many times.
// When the copy can be forgot, the copied message must be finished with Finish() message to release the memory
func CopyMessage(ctx context.Context, m binding.Message, transformers ...binding.TransformerFactory) (binding.Message, error) {
originalMessageEncoding := m.Encoding()
if originalMessageEncoding == binding.EncodingUnknown {
return nil, binding.ErrUnknownEncoding
}
if originalMessageEncoding == binding.EncodingEvent {
e, _, err := binding.ToEvent(ctx, m, transformers...)
if err != nil {
return nil, err
}
return binding.EventMessage(e), nil
}
sm := structBufferedMessage{}
bm := binaryBufferedMessage{}
encoding, err := binding.RunDirectEncoding(ctx, m, &sm, &bm, transformers)
if encoding == binding.EncodingStructured {
return &sm, err
} else if encoding == binding.EncodingBinary {
return &bm, err
} else {
e, _, err := binding.ToEvent(ctx, m, transformers...)
if err != nil {
return nil, err
}
return binding.EventMessage(e), nil
}
}