Josh Hawn
9c05f0eaf9
To avoid an expensive call to archive.ChangesDirs() which walks two directory trees and compares every entry, archive.ApplyLayer() has been extended to also return the size of the layer changes. Docker-DCO-1.1-Signed-off-by: Josh Hawn <josh.hawn@docker.com> (github: jlhawn) Upstream-commit: 35a22c9e12c05e2a0a205964702ced78ea39d7a1 Component: engine
88 lines
1.8 KiB
Go
88 lines
1.8 KiB
Go
package chrootarchive
|
|
|
|
import (
|
|
"bytes"
|
|
"encoding/json"
|
|
"flag"
|
|
"fmt"
|
|
"io"
|
|
"io/ioutil"
|
|
"os"
|
|
"path/filepath"
|
|
"runtime"
|
|
"syscall"
|
|
|
|
"github.com/docker/docker/pkg/archive"
|
|
"github.com/docker/docker/pkg/reexec"
|
|
)
|
|
|
|
type applyLayerResponse struct {
|
|
LayerSize int64 `json:"layerSize"`
|
|
}
|
|
|
|
func applyLayer() {
|
|
runtime.LockOSThread()
|
|
flag.Parse()
|
|
|
|
if err := chroot(flag.Arg(0)); err != nil {
|
|
fatal(err)
|
|
}
|
|
|
|
// We need to be able to set any perms
|
|
oldmask := syscall.Umask(0)
|
|
defer syscall.Umask(oldmask)
|
|
tmpDir, err := ioutil.TempDir("/", "temp-docker-extract")
|
|
if err != nil {
|
|
fatal(err)
|
|
}
|
|
|
|
os.Setenv("TMPDIR", tmpDir)
|
|
size, err := archive.UnpackLayer("/", os.Stdin)
|
|
os.RemoveAll(tmpDir)
|
|
if err != nil {
|
|
fatal(err)
|
|
}
|
|
|
|
encoder := json.NewEncoder(os.Stdout)
|
|
if err := encoder.Encode(applyLayerResponse{size}); err != nil {
|
|
fatal(fmt.Errorf("unable to encode layerSize JSON: %s", err))
|
|
}
|
|
|
|
flush(os.Stdout)
|
|
flush(os.Stdin)
|
|
os.Exit(0)
|
|
}
|
|
|
|
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 func() {
|
|
if c, ok := decompressed.(io.Closer); ok {
|
|
c.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
|
|
}
|