Currently, `image.GetDiffID` cannot calculate DiffID of zstd layers because it directly uses `compress/gzip` decompressor. This commit fixes this issue by using the generic decompressor. Signed-off-by: Kohei Tokunaga <ktokunaga.mail@gmail.com>
		
			
				
	
	
		
			82 lines
		
	
	
		
			2.4 KiB
		
	
	
	
		
			Go
		
	
	
	
	
	
			
		
		
	
	
			82 lines
		
	
	
		
			2.4 KiB
		
	
	
	
		
			Go
		
	
	
	
	
	
/*
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   Copyright The containerd Authors.
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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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       http://www.apache.org/licenses/LICENSE-2.0
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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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*/
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package images
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import (
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	"context"
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	"io"
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	"github.com/containerd/containerd/archive/compression"
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	"github.com/containerd/containerd/content"
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	"github.com/containerd/containerd/labels"
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	"github.com/opencontainers/go-digest"
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	ocispec "github.com/opencontainers/image-spec/specs-go/v1"
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	"github.com/sirupsen/logrus"
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)
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// GetDiffID gets the diff ID of the layer blob descriptor.
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func GetDiffID(ctx context.Context, cs content.Store, desc ocispec.Descriptor) (digest.Digest, error) {
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	switch desc.MediaType {
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	case
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		// If the layer is already uncompressed, we can just return its digest
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		MediaTypeDockerSchema2Layer,
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		ocispec.MediaTypeImageLayer,
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		MediaTypeDockerSchema2LayerForeign,
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		ocispec.MediaTypeImageLayerNonDistributable:
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		return desc.Digest, nil
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	}
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	info, err := cs.Info(ctx, desc.Digest)
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	if err != nil {
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		return "", err
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	}
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	v, ok := info.Labels[labels.LabelUncompressed]
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	if ok {
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		// Fast path: if the image is already unpacked, we can use the label value
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		return digest.Parse(v)
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	}
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	// if the image is not unpacked, we may not have the label
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	ra, err := cs.ReaderAt(ctx, desc)
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	if err != nil {
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		return "", err
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	}
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	defer ra.Close()
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	r := content.NewReader(ra)
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	uR, err := compression.DecompressStream(r)
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	if err != nil {
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		return "", err
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	}
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	defer uR.Close()
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	digester := digest.Canonical.Digester()
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	hashW := digester.Hash()
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	if _, err := io.Copy(hashW, uR); err != nil {
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		return "", err
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	}
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	if err := ra.Close(); err != nil {
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		return "", err
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	}
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	digest := digester.Digest()
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	// memorize the computed value
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	if info.Labels == nil {
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		info.Labels = make(map[string]string)
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	}
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	info.Labels[labels.LabelUncompressed] = digest.String()
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	if _, err := cs.Update(ctx, info, "labels"); err != nil {
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		logrus.WithError(err).Warnf("failed to set %s label for %s", labels.LabelUncompressed, desc.Digest)
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	}
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	return digest, nil
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}
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