163 lines
4.0 KiB
Go
163 lines
4.0 KiB
Go
package graphdriver
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import (
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"fmt"
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"time"
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"github.com/docker/docker/archive"
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"github.com/docker/docker/pkg/ioutils"
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"github.com/docker/docker/pkg/log"
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"github.com/docker/docker/utils"
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)
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// GenericDriverWrapper takes a generic Driver and adds the
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// capability of the following methods which it doesn't
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// support on its own:
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// Diff(id, parent string) (archive.Archive, error)
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// Changes(id, parent string) ([]archive.Change, error)
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// ApplyDiff(id, parent string, diff archive.ArchiveReader) (bytes int64, err error)
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// DiffSize(id, parent string) (bytes int64, err error)
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// Notably, the AUFS driver doesn't need to be wrapped like this.
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type GenericDriverWrapper struct {
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GenericDriver
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}
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// NewGenericDriverWrapper returns a fully functional driver that wraps the given GenericDriver.
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func NewGenericDriverWrapper(driver GenericDriver) Driver {
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return &GenericDriverWrapper{GenericDriver: driver}
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}
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// Diff produces an archive of the changes between the specified
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// layer and its parent layer which may be "".
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func (gdw *GenericDriverWrapper) Diff(id, parent string) (arch archive.Archive, err error) {
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driver := gdw.GenericDriver
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layerFs, err := driver.Get(id, "")
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if err != nil {
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return nil, err
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}
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defer func() {
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if err != nil {
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driver.Put(id)
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}
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}()
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if parent == "" {
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archive, err := archive.Tar(layerFs, archive.Uncompressed)
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if err != nil {
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return nil, err
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}
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return ioutils.NewReadCloserWrapper(archive, func() error {
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err := archive.Close()
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driver.Put(id)
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return err
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}), nil
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}
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parentFs, err := driver.Get(parent, "")
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if err != nil {
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return nil, err
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}
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defer driver.Put(parent)
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changes, err := archive.ChangesDirs(layerFs, parentFs)
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if err != nil {
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return nil, err
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}
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archive, err := archive.ExportChanges(layerFs, changes)
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if err != nil {
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return nil, err
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}
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return ioutils.NewReadCloserWrapper(archive, func() error {
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err := archive.Close()
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driver.Put(id)
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return err
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}), nil
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}
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// Changes produces a list of changes between the specified layer
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// and its parent layer. If parent is "", then all changes will be ADD changes.
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func (gdw *GenericDriverWrapper) Changes(id, parent string) ([]archive.Change, error) {
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driver := gdw.GenericDriver
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layerFs, err := driver.Get(id, "")
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if err != nil {
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return nil, err
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}
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defer driver.Put(id)
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parentFs := ""
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if parent != "" {
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parentFs, err = driver.Get(parent, "")
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if err != nil {
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return nil, err
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}
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defer driver.Put(parent)
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}
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return archive.ChangesDirs(layerFs, parentFs)
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}
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// ApplyDiff extracts the changeset from the given diff into the
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// layer with the specified id and parent, returning the size of the
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// new layer in bytes.
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func (gdw *GenericDriverWrapper) ApplyDiff(id, parent string, diff archive.ArchiveReader) (bytes int64, err error) {
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driver := gdw.GenericDriver
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// Mount the root filesystem so we can apply the diff/layer.
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layerFs, err := driver.Get(id, "")
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if err != nil {
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return
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}
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defer driver.Put(id)
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start := time.Now().UTC()
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log.Debugf("Start untar layer")
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if err = archive.ApplyLayer(layerFs, diff); err != nil {
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return
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}
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log.Debugf("Untar time: %vs", time.Now().UTC().Sub(start).Seconds())
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if parent == "" {
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return utils.TreeSize(layerFs)
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}
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parentFs, err := driver.Get(parent, "")
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if err != nil {
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err = fmt.Errorf("Driver %s failed to get image parent %s: %s", driver, parent, err)
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return
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}
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defer driver.Put(parent)
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changes, err := archive.ChangesDirs(layerFs, parentFs)
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if err != nil {
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return
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}
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return archive.ChangesSize(layerFs, changes), nil
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}
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// DiffSize calculates the changes between the specified layer
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// and its parent and returns the size in bytes of the changes
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// relative to its base filesystem directory.
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func (gdw *GenericDriverWrapper) DiffSize(id, parent string) (bytes int64, err error) {
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driver := gdw.GenericDriver
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changes, err := gdw.Changes(id, parent)
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if err != nil {
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return
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}
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layerFs, err := driver.Get(id, "")
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if err != nil {
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return
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}
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defer driver.Put(id)
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return archive.ChangesSize(layerFs, changes), nil
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}
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