73 lines
1.5 KiB
Go
73 lines
1.5 KiB
Go
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package devmapper
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import (
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"github.com/dotcloud/docker/archive"
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)
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type Image interface {
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ID() string
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Parent() (Image, error)
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Path() string
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}
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type DMBackend struct {
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*DeviceSet
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}
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func (b *DMBackend) Init(home string) error {
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b.DeviceSet = NewDeviceSet(home)
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if err := b.DeviceSet.ensureInit(); 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 (b *DMBackend) Shutdown() error {
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return b.DeviceSet.Shutdown()
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}
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func (b *DMBackend) Create(img image, layer archive.Archive) error {
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// Determine the source of the snapshot (parent id or init device)
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var parentID string
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if parent, err := img.Parent(); err != nil {
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return err
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} else if parent != nil {
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parentID = parent.ID()
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}
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// Create the device for this image by snapshotting source
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if err := b.DeviceSet.AddDevice(img.ID(), parentID); err != nil {
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return err
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}
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// Mount the device in rootfs
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mp := b.mountpoint(id)
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if err := os.MkdirAll(mp); err != nil {
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return err
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}
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if err := b.DeviceSet.MountDevice(id, mp, false); err != nil {
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return err
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}
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// Apply the layer as a diff
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if layer != nil {
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if err := archive.ApplyLayer(mp, layer); err != nil {
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return err
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}
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}
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return nil
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}
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func (b *DMBackend) mountpoint(id string) string {
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if b.home == "" {
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return ""
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}
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return path.Join(b.home, "mnt", id)
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}
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func (b *DMBackend) Changes(img *Image, dest string) ([]Change, error) {
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return nil, fmt.Errorf("Not implemented")
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}
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func (b *DMBackend) Layer(img *Image, dest string) (Archive, error) {
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return nil, fmt.Errorf("Not implemented")
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}
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