Function OpenWriter

core/content/helpers.go:149–182

OpenWriter opens a new writer for the given reference, retrying if the writer is locked until the reference is available or returns an error.

(ctx context.Context, cs Ingester, opts ...WriterOpt)

// OpenWriter opens a new writer for the given reference, retrying if the writer
// is locked until the reference is available or returns an error.
func OpenWriter(ctx context.Context, cs Ingester, opts ...WriterOpt) (Writer, error) {
	var (
		cw    Writer
		err   error
		retry = 16
	)
	for {
		cw, err = cs.Writer(ctx, opts...)
		if err != nil {
			if !errdefs.IsUnavailable(err) {
				return nil, err
			}

			// TODO: Check status to determine if the writer is active,
			// continue waiting while active, otherwise return lock
			// error or abort. Requires asserting for an ingest manager

			select {
			case <-time.After(time.Millisecond * time.Duration(randutil.Intn(retry))):
				if retry < 2048 {
					retry = retry << 1
				}
				continue
			case <-ctx.Done():
				// Propagate lock error
				return nil, err
			}

		}
		break
	}

	return cw, err
}

// Copy copies data with the expected digest from the reader into the
// provided content store writer. This copy commits the writer.