3ae69c43d8
Add snapshot subcommand to ctr for creating diffs of RW layers. Signed-off-by: Derek McGowan <derek@mcgstyle.net>
53 lines
1.3 KiB
Go
53 lines
1.3 KiB
Go
package rootfs
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import (
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"context"
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"fmt"
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"github.com/containerd/containerd"
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"github.com/containerd/containerd/content"
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"github.com/containerd/containerd/snapshot"
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ocispec "github.com/opencontainers/image-spec/specs-go/v1"
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)
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type MountDiffer interface {
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DiffMounts(ctx context.Context, lower, upper []containerd.Mount, media, ref string) (ocispec.Descriptor, error)
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}
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type DiffOptions struct {
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MountDiffer
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content.Store
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snapshot.Snapshotter
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}
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func Diff(ctx context.Context, snapshotID, contentRef string, sn snapshot.Snapshotter, md MountDiffer) (ocispec.Descriptor, error) {
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info, err := sn.Stat(ctx, snapshotID)
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if err != nil {
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return ocispec.Descriptor{}, err
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}
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lowerKey := fmt.Sprintf("%s-parent-view", info.Parent)
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lower, err := sn.View(ctx, lowerKey, info.Parent)
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if err != nil {
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return ocispec.Descriptor{}, err
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}
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defer sn.Remove(ctx, lowerKey)
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var upper []containerd.Mount
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if info.Kind == snapshot.KindActive {
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upper, err = sn.Mounts(ctx, snapshotID)
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if err != nil {
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return ocispec.Descriptor{}, err
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}
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} else {
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upperKey := fmt.Sprintf("%s-view", snapshotID)
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upper, err = sn.View(ctx, upperKey, snapshotID)
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if err != nil {
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return ocispec.Descriptor{}, err
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}
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defer sn.Remove(ctx, lowerKey)
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}
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return md.DiffMounts(ctx, lower, upper, ocispec.MediaTypeImageLayer, contentRef)
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}
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