// Changes produces a list of changes between the specified layer
// and its parent layer. If parent is "", then all changes will be ADD changes.
// The layer should be mounted when calling this function
func (d *Driver) Changes(id, parent string) ([]archive.Change, error) {
rID, err := d.resolveID(id)
if err != nil {
return nil, err
}
parentChain, err := d.getLayerChain(rID)
if err != nil {
return nil, err
}
// this is assuming that the layer is unmounted
if err := hcsshim.UnprepareLayer(d.info, rID); err != nil {
return nil, err
}
defer func() {
if err := hcsshim.PrepareLayer(d.info, rID, parentChain); err != nil {
logrus.Warnf("Failed to Deactivate %s: %s", rID, err)
}
}()
var changes []archive.Change
err = winio.RunWithPrivilege(winio.SeBackupPrivilege, func() error {
r, err := hcsshim.NewLayerReader(d.info, id, parentChain)
if err != nil {
return err
}
defer r.Close()
for {
name, _, fileInfo, err := r.Next()
if err == io.EOF {
return nil
}
if err != nil {
return err
}
name = filepath.ToSlash(name)
if fileInfo == nil {
changes = append(changes, archive.Change{Path: name, Kind: archive.ChangeDelete})
} else {
// Currently there is no way to tell between an add and a modify.
changes = append(changes, archive.Change{Path: name, Kind: archive.ChangeModify})
}
}
})
if err != nil {
return nil, err
}
return changes, nil
}
// exportLayer generates an archive from a layer based on the given ID.
func (d *Driver) exportLayer(id string, parentLayerPaths []string) (archive.Archive, error) {
if hcsshim.IsTP4() {
// Export in TP4 format to maintain compatibility with existing images and
// because ExportLayer is somewhat broken on TP4 and can't work with the new
// scheme.
tempFolder, err := ioutil.TempDir("", "hcs")
if err != nil {
return nil, err
}
defer func() {
if err != nil {
os.RemoveAll(tempFolder)
}
}()
if err = hcsshim.ExportLayer(d.info, id, tempFolder, parentLayerPaths); err != nil {
return nil, err
}
archive, err := archive.Tar(tempFolder, archive.Uncompressed)
if err != nil {
return nil, err
}
return ioutils.NewReadCloserWrapper(archive, func() error {
err := archive.Close()
os.RemoveAll(tempFolder)
return err
}), nil
}
var r hcsshim.LayerReader
r, err := hcsshim.NewLayerReader(d.info, id, parentLayerPaths)
if err != nil {
return nil, err
}
archive, w := io.Pipe()
go func() {
err := writeTarFromLayer(r, w)
cerr := r.Close()
if err == nil {
err = cerr
}
w.CloseWithError(err)
}()
return archive, nil
}
// exportLayer generates an archive from a layer based on the given ID.
func (d *Driver) exportLayer(id string, parentLayerPaths []string) (archive.Archive, error) {
var r hcsshim.LayerReader
r, err := hcsshim.NewLayerReader(d.info, id, parentLayerPaths)
if err != nil {
return nil, err
}
archive, w := io.Pipe()
go func() {
err := writeTarFromLayer(r, w)
cerr := r.Close()
if err == nil {
err = cerr
}
w.CloseWithError(err)
}()
return archive, nil
}
// exportLayer generates an archive from a layer based on the given ID.
func (d *Driver) exportLayer(id string, parentLayerPaths []string) (archive.Archive, error) {
archive, w := io.Pipe()
go func() {
err := winio.RunWithPrivilege(winio.SeBackupPrivilege, func() error {
r, err := hcsshim.NewLayerReader(d.info, id, parentLayerPaths)
if err != nil {
return err
}
err = writeTarFromLayer(r, w)
cerr := r.Close()
if err == nil {
err = cerr
}
return err
})
w.CloseWithError(err)
}()
return archive, nil
}
// Changes produces a list of changes between the specified layer
// and its parent layer. If parent is "", then all changes will be ADD changes.
func (d *Driver) Changes(id, parent string) ([]archive.Change, error) {
rID, err := d.resolveID(id)
if err != nil {
return nil, err
}
parentChain, err := d.getLayerChain(rID)
if err != nil {
return nil, err
}
d.Lock()
if d.info.Flavour == filterDriver {
if d.active[rID] == 0 {
if err = hcsshim.ActivateLayer(d.info, rID); err != nil {
d.Unlock()
return nil, err
}
defer func() {
if err := hcsshim.DeactivateLayer(d.info, rID); err != nil {
logrus.Warnf("Failed to Deactivate %s: %s", rID, err)
}
}()
} else {
if err = hcsshim.UnprepareLayer(d.info, rID); err != nil {
d.Unlock()
return nil, err
}
defer func() {
if err := hcsshim.PrepareLayer(d.info, rID, parentChain); err != nil {
logrus.Warnf("Failed to re-PrepareLayer %s: %s", rID, err)
}
}()
}
}
d.Unlock()
r, err := hcsshim.NewLayerReader(d.info, id, parentChain)
if err != nil {
return nil, err
}
defer r.Close()
var changes []archive.Change
for {
name, _, fileInfo, err := r.Next()
if err == io.EOF {
break
}
if err != nil {
return nil, err
}
name = filepath.ToSlash(name)
if fileInfo == nil {
changes = append(changes, archive.Change{name, archive.ChangeDelete})
} else {
// Currently there is no way to tell between an add and a modify.
changes = append(changes, archive.Change{name, archive.ChangeModify})
}
}
return changes, nil
}