76 lines
1.7 KiB
Go
76 lines
1.7 KiB
Go
package containerd
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import (
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"context"
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"encoding/json"
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"github.com/containerd/containerd/content"
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"github.com/containerd/containerd/images"
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"github.com/containerd/containerd/rootfs"
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ocispec "github.com/opencontainers/image-spec/specs-go/v1"
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"github.com/pkg/errors"
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)
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type Image interface {
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Name() string
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Target() ocispec.Descriptor
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Unpack(context.Context) error
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}
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var _ = (Image)(&image{})
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type image struct {
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client *Client
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i images.Image
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}
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func (i *image) Name() string {
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return i.i.Name
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}
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func (i *image) Target() ocispec.Descriptor {
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return i.i.Target
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}
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func (i *image) Unpack(ctx context.Context) error {
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layers, err := i.getLayers(ctx)
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if err != nil {
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return err
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}
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if _, err := rootfs.ApplyLayers(ctx, layers, i.client.SnapshotService(), i.client.DiffService()); err != nil {
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return err
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}
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return nil
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}
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func (i *image) getLayers(ctx context.Context) ([]rootfs.Layer, error) {
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cs := i.client.ContentStore()
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p, err := content.ReadBlob(ctx, cs, i.i.Target.Digest)
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if err != nil {
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return nil, errors.Wrapf(err, "failed to read manifest blob")
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}
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var manifest ocispec.Manifest
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if err := json.Unmarshal(p, &manifest); err != nil {
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return nil, errors.Wrap(err, "failed to unmarshal manifest")
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}
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diffIDs, err := i.i.RootFS(ctx, cs)
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if err != nil {
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return nil, errors.Wrap(err, "failed to resolve rootfs")
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}
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if len(diffIDs) != len(manifest.Layers) {
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return nil, errors.Errorf("mismatched image rootfs and manifest layers")
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}
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layers := make([]rootfs.Layer, len(diffIDs))
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for i := range diffIDs {
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layers[i].Diff = ocispec.Descriptor{
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// TODO: derive media type from compressed type
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MediaType: ocispec.MediaTypeImageLayer,
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Digest: diffIDs[i],
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}
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layers[i].Blob = manifest.Layers[i]
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}
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return layers, nil
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}
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