Golang BlobWriter.ReadFrom方法代码示例

func (pd *v2PushDescriptor) uploadUsingSession(
	ctx context.Context,
	progressOutput progress.Output,
	diffID layer.DiffID,
	layerUpload distribution.BlobWriter,
) (distribution.Descriptor, error) {
	arch, err := pd.layer.TarStream()
	if err != nil {
		return distribution.Descriptor{}, xfer.DoNotRetry{Err: err}
	}

	// don't care if this fails; best effort
	size, _ := pd.layer.DiffSize()

	reader := progress.NewProgressReader(ioutils.NewCancelReadCloser(ctx, arch), progressOutput, size, pd.ID(), "Pushing")
	compressedReader, compressionDone := compress(reader)
	defer func() {
		reader.Close()
		<-compressionDone
	}()

	digester := digest.Canonical.New()
	tee := io.TeeReader(compressedReader, digester.Hash())

	nn, err := layerUpload.ReadFrom(tee)
	compressedReader.Close()
	if err != nil {
		return distribution.Descriptor{}, retryOnError(err)
	}

	pushDigest := digester.Digest()
	if _, err := layerUpload.Commit(ctx, distribution.Descriptor{Digest: pushDigest}); err != nil {
		return distribution.Descriptor{}, retryOnError(err)
	}

	logrus.Debugf("uploaded layer %s (%s), %d bytes", diffID, pushDigest, nn)
	progress.Update(progressOutput, pd.ID(), "Pushed")

	// Cache mapping from this layer's DiffID to the blobsum
	if err := pd.v2MetadataService.TagAndAdd(diffID, pd.hmacKey, metadata.V2Metadata{
		Digest:           pushDigest,
		SourceRepository: pd.repoInfo.FullName(),
	}); err != nil {
		return distribution.Descriptor{}, xfer.DoNotRetry{Err: err}
	}

	desc := distribution.Descriptor{
		Digest:    pushDigest,
		MediaType: schema2.MediaTypeLayer,
		Size:      nn,
	}

	pd.pushState.Lock()
	// If Commit succeeded, that's an indication that the remote registry speaks the v2 protocol.
	pd.pushState.confirmedV2 = true
	pd.pushState.remoteLayers[diffID] = desc
	pd.pushState.Unlock()

	return desc, nil
}

//.........这里部分代码省略.........
		if err != nil {
			continue
		}

		canonicalRef, err := distreference.WithDigest(remoteRef, mountFrom.Digest)
		if err != nil {
			continue
		}

		logrus.Debugf("attempting to mount layer %s (%s) from %s", diffID, mountFrom.Digest, sourceRepo.FullName())

		layerUpload, err = bs.Create(ctx, client.WithMountFrom(canonicalRef))
		switch err := err.(type) {
		case distribution.ErrBlobMounted:
			progress.Updatef(progressOutput, pd.ID(), "Mounted from %s", err.From.Name())

			err.Descriptor.MediaType = schema2.MediaTypeLayer

			pd.pushState.Lock()
			pd.pushState.confirmedV2 = true
			pd.pushState.remoteLayers[diffID] = err.Descriptor
			pd.pushState.Unlock()

			// Cache mapping from this layer's DiffID to the blobsum
			if err := pd.v2MetadataService.Add(diffID, metadata.V2Metadata{Digest: mountFrom.Digest, SourceRepository: pd.repoInfo.FullName()}); err != nil {
				return xfer.DoNotRetry{Err: err}
			}
			return nil
		case nil:
			// blob upload session created successfully, so begin the upload
			mountAttemptsRemaining = 0
		default:
			// unable to mount layer from this repository, so this source mapping is no longer valid
			logrus.Debugf("unassociating layer %s (%s) with %s", diffID, mountFrom.Digest, mountFrom.SourceRepository)
			pd.v2MetadataService.Remove(mountFrom)
			mountAttemptsRemaining--
		}
	}

	if layerUpload == nil {
		layerUpload, err = bs.Create(ctx)
		if err != nil {
			return retryOnError(err)
		}
	}
	defer layerUpload.Close()

	arch, err := pd.layer.TarStream()
	if err != nil {
		return xfer.DoNotRetry{Err: err}
	}

	// don't care if this fails; best effort
	size, _ := pd.layer.DiffSize()

	reader := progress.NewProgressReader(ioutils.NewCancelReadCloser(ctx, arch), progressOutput, size, pd.ID(), "Pushing")
	compressedReader, compressionDone := compress(reader)
	defer func() {
		reader.Close()
		<-compressionDone
	}()

	digester := digest.Canonical.New()
	tee := io.TeeReader(compressedReader, digester.Hash())

	nn, err := layerUpload.ReadFrom(tee)
	compressedReader.Close()
	if err != nil {
		return retryOnError(err)
	}

	pushDigest := digester.Digest()
	if _, err := layerUpload.Commit(ctx, distribution.Descriptor{Digest: pushDigest}); err != nil {
		return retryOnError(err)
	}

	logrus.Debugf("uploaded layer %s (%s), %d bytes", diffID, pushDigest, nn)
	progress.Update(progressOutput, pd.ID(), "Pushed")

	// Cache mapping from this layer's DiffID to the blobsum
	if err := pd.v2MetadataService.Add(diffID, metadata.V2Metadata{Digest: pushDigest, SourceRepository: pd.repoInfo.FullName()}); err != nil {
		return xfer.DoNotRetry{Err: err}
	}

	pd.pushState.Lock()

	// If Commit succeeded, that's an indication that the remote registry
	// speaks the v2 protocol.
	pd.pushState.confirmedV2 = true

	pd.pushState.remoteLayers[diffID] = distribution.Descriptor{
		Digest:    pushDigest,
		MediaType: schema2.MediaTypeLayer,
		Size:      nn,
	}

	pd.pushState.Unlock()

	return nil
}