func ApplyLayer(dest string, layer archive.ArchiveReader) (size int64, err error) {
dest = filepath.Clean(dest)
decompressed, err := archive.DecompressStream(layer)
if err != nil {
return 0, err
}
defer decompressed.Close()
cmd := reexec.Command("docker-applyLayer", dest)
cmd.Stdin = decompressed
outBuf, errBuf := new(bytes.Buffer), new(bytes.Buffer)
cmd.Stdout, cmd.Stderr = outBuf, errBuf
if err = cmd.Run(); err != nil {
return 0, fmt.Errorf("ApplyLayer %s stdout: %s stderr: %s", err, outBuf, errBuf)
}
// Stdout should be a valid JSON struct representing an applyLayerResponse.
response := applyLayerResponse{}
decoder := json.NewDecoder(outBuf)
if err = decoder.Decode(&response); err != nil {
return 0, fmt.Errorf("unable to decode ApplyLayer JSON response: %s", err)
}
return response.LayerSize, nil
}
// applyLayerHandler parses a diff in the standard layer format from `layer`, and
// applies it to the directory `dest`. Returns the size in bytes of the
// contents of the layer.
func applyLayerHandler(dest string, layer archive.Reader, options *archive.TarOptions, decompress bool) (size int64, err error) {
dest = filepath.Clean(dest)
if decompress {
decompressed, err := archive.DecompressStream(layer)
if err != nil {
return 0, err
}
defer decompressed.Close()
layer = decompressed
}
if options == nil {
options = &archive.TarOptions{}
}
if options.ExcludePatterns == nil {
options.ExcludePatterns = []string{}
}
data, err := json.Marshal(options)
if err != nil {
return 0, fmt.Errorf("ApplyLayer json encode: %v", err)
}
cmd := reexec.Command("docker-applyLayer", dest)
cmd.Stdin = layer
cmd.Env = append(cmd.Env, fmt.Sprintf("OPT=%s", data))
outBuf, errBuf := new(bytes.Buffer), new(bytes.Buffer)
cmd.Stdout, cmd.Stderr = outBuf, errBuf
if err = cmd.Run(); err != nil {
return 0, fmt.Errorf("ApplyLayer %s stdout: %s stderr: %s", err, outBuf, errBuf)
}
// Stdout should be a valid JSON struct representing an applyLayerResponse.
response := applyLayerResponse{}
decoder := json.NewDecoder(outBuf)
if err = decoder.Decode(&response); err != nil {
return 0, fmt.Errorf("unable to decode ApplyLayer JSON response: %s", err)
}
return response.LayerSize, nil
}
func Untar(tarArchive io.Reader, dest string, options *archive.TarOptions) error {
if tarArchive == nil {
return fmt.Errorf("Empty archive")
}
if options == nil {
options = &archive.TarOptions{}
}
if options.ExcludePatterns == nil {
options.ExcludePatterns = []string{}
}
dest = filepath.Clean(dest)
if _, err := os.Stat(dest); os.IsNotExist(err) {
if err := os.MkdirAll(dest, 0777); err != nil {
return err
}
}
// We can't pass the exclude list directly via cmd line
// because we easily overrun the shell max argument list length
// when the full image list is passed (e.g. when this is used
// by `docker load`). Instead we will add the JSON marshalled
// and placed in the env, which has significantly larger
// max size
data, err := json.Marshal(options)
if err != nil {
return fmt.Errorf("Untar json encode: %v", err)
}
decompressedArchive, err := archive.DecompressStream(tarArchive)
if err != nil {
return err
}
defer decompressedArchive.Close()
cmd := reexec.Command("docker-untar", dest)
cmd.Stdin = decompressedArchive
cmd.Env = append(cmd.Env, fmt.Sprintf("OPT=%s", data))
out, err := cmd.CombinedOutput()
if err != nil {
return fmt.Errorf("Untar %s %s", err, out)
}
return nil
}
func invokeUnpack(decompressedArchive io.Reader, dest string, options *archive.TarOptions) error {
// We can't pass a potentially large exclude list directly via cmd line
// because we easily overrun the kernel's max argument/environment size
// when the full image list is passed (e.g. when this is used by
// `docker load`). We will marshall the options via a pipe to the
// child
r, w, err := os.Pipe()
if err != nil {
return fmt.Errorf("Untar pipe failure: %v", err)
}
cmd := reexec.Command("docker-untar", dest)
cmd.Stdin = decompressedArchive
cmd.ExtraFiles = append(cmd.ExtraFiles, r)
output := bytes.NewBuffer(nil)
cmd.Stdout = output
cmd.Stderr = output
if err := cmd.Start(); err != nil {
return fmt.Errorf("Untar error on re-exec cmd: %v", err)
}
//write the options to the pipe for the untar exec to read
if err := json.NewEncoder(w).Encode(options); err != nil {
return fmt.Errorf("Untar json encode to pipe failed: %v", err)
}
w.Close()
if err := cmd.Wait(); err != nil {
// when `xz -d -c -q | docker-untar ...` failed on docker-untar side,
// we need to exhaust `xz`'s output, otherwise the `xz` side will be
// pending on write pipe forever
io.Copy(ioutil.Discard, decompressedArchive)
return fmt.Errorf("Untar re-exec error: %v: output: %s", err, output)
}
return nil
}
func Untar(tarArchive io.Reader, dest string, options *archive.TarOptions) error {
if tarArchive == nil {
return fmt.Errorf("Empty archive")
}
if options == nil {
options = &archive.TarOptions{}
}
if options.Excludes == nil {
options.Excludes = []string{}
}
var (
buf bytes.Buffer
enc = json.NewEncoder(&buf)
)
if err := enc.Encode(options); err != nil {
return fmt.Errorf("Untar json encode: %v", err)
}
if _, err := os.Stat(dest); os.IsNotExist(err) {
if err := os.MkdirAll(dest, 0777); err != nil {
return err
}
}
dest = filepath.Clean(dest)
decompressedArchive, err := archive.DecompressStream(tarArchive)
if err != nil {
return err
}
defer decompressedArchive.Close()
cmd := reexec.Command("docker-untar", dest, buf.String())
cmd.Stdin = decompressedArchive
out, err := cmd.CombinedOutput()
if err != nil {
return fmt.Errorf("Untar %s %s", err, out)
}
return nil
}