// DiffGetter returns a FileGetCloser that can read files from the directory that
// contains files for the layer differences. Used for direct access for tar-split.
func (d *Driver) DiffGetter(id string) (graphdriver.FileGetCloser, error) {
id, err := d.resolveID(id)
if err != nil {
return nil, err
}
if hcsshim.IsTP4() {
// The export format for TP4 is different from the contents of the layer, so
// fall back to exporting the layer and getting file contents from there.
layerChain, err := d.getLayerChain(id)
if err != nil {
return nil, err
}
var tempFolder string
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, layerChain); err != nil {
return nil, err
}
return &fileGetDestroyCloser{storage.NewPathFileGetter(tempFolder), tempFolder}, nil
}
return &fileGetCloserWithBackupPrivileges{d.dir(id)}, 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
}
// DiffPath returns a directory that contains files needed to construct layer diff.
func (d *Driver) DiffPath(id string) (path string, release func() error, err error) {
id, err = d.resolveID(id)
if err != nil {
return
}
// Getting the layer paths must be done outside of the lock.
layerChain, err := d.getLayerChain(id)
if err != nil {
return
}
layerFolder := d.dir(id)
tempFolder := layerFolder + "-" + strconv.FormatUint(uint64(random.Rand.Uint32()), 10)
if err = os.MkdirAll(tempFolder, 0755); err != nil {
logrus.Errorf("Could not create %s %s", tempFolder, err)
return
}
defer func() {
if err != nil {
_, folderName := filepath.Split(tempFolder)
if err2 := hcsshim.DestroyLayer(d.info, folderName); err2 != nil {
logrus.Warnf("Couldn't clean-up tempFolder: %s %s", tempFolder, err2)
}
}
}()
if err = hcsshim.ExportLayer(d.info, id, tempFolder, layerChain); err != nil {
return
}
err = copySysFiles(filepath.Join(d.info.HomeDir, "sysfile-backups", id), tempFolder)
if err != nil {
return
}
return tempFolder, func() error {
// TODO: activate layers and release here?
_, folderName := filepath.Split(tempFolder)
return hcsshim.DestroyLayer(d.info, folderName)
}, nil
}
func (d *WindowsGraphDriver) Export(id string, parentLayerPaths []string) (arch archive.Archive, err error) {
layerFs, err := d.Get(id, "")
if err != nil {
return
}
defer func() {
if err != nil {
d.Put(id)
}
}()
tempFolder := layerFs + "-temp"
if err = os.MkdirAll(tempFolder, 0755); err != nil {
logrus.Errorf("Could not create %s %s", tempFolder, err)
return
}
defer func() {
if err != nil {
if err2 := os.RemoveAll(tempFolder); err2 != nil {
logrus.Warnf("Couldn't clean-up tempFolder: %s %s", tempFolder, err2)
}
}
}()
if err = hcsshim.ExportLayer(d.info, id, tempFolder, parentLayerPaths); err != nil {
return
}
archive, err := archive.Tar(tempFolder, archive.Uncompressed)
if err != nil {
return
}
return ioutils.NewReadCloserWrapper(archive, func() error {
err := archive.Close()
d.Put(id)
if err2 := os.RemoveAll(tempFolder); err2 != nil {
logrus.Warnf("Couldn't clean-up tempFolder: %s %s", tempFolder, err2)
}
return err
}), nil
}
// exportLayer generates an archive from a layer based on the given ID.
func (d *Driver) exportLayer(id string, parentLayerPaths []string) (arch archive.Archive, err error) {
layerFolder := d.dir(id)
tempFolder := layerFolder + "-" + strconv.FormatUint(uint64(random.Rand.Uint32()), 10)
if err = os.MkdirAll(tempFolder, 0755); err != nil {
logrus.Errorf("Could not create %s %s", tempFolder, err)
return
}
defer func() {
if err != nil {
_, folderName := filepath.Split(tempFolder)
if err2 := hcsshim.DestroyLayer(d.info, folderName); err2 != nil {
logrus.Warnf("Couldn't clean-up tempFolder: %s %s", tempFolder, err2)
}
}
}()
if err = hcsshim.ExportLayer(d.info, id, tempFolder, parentLayerPaths); err != nil {
return
}
archive, err := archive.Tar(tempFolder, archive.Uncompressed)
if err != nil {
return
}
return ioutils.NewReadCloserWrapper(archive, func() error {
err := archive.Close()
d.Put(id)
_, folderName := filepath.Split(tempFolder)
if err2 := hcsshim.DestroyLayer(d.info, folderName); err2 != nil {
logrus.Warnf("Couldn't clean-up tempFolder: %s %s", tempFolder, err2)
}
return err
}), nil
}
