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moby--moby/archive.go
unclejack 3c5d2e4661 add support for xz compression
This adds xz as a compression option.
xz is alread supported by bsdtar without the external xz program.
2013-04-02 02:16:28 +03:00

88 lines
1.8 KiB
Go

package docker
import (
"errors"
"io"
"io/ioutil"
"os/exec"
)
type Archive io.Reader
type Compression uint32
const (
Uncompressed Compression = iota
Bzip2
Gzip
Xz
)
func (compression *Compression) Flag() string {
switch *compression {
case Bzip2:
return "j"
case Gzip:
return "z"
case Xz:
return "J"
}
return ""
}
func Tar(path string, compression Compression) (io.Reader, error) {
cmd := exec.Command("bsdtar", "-f", "-", "-C", path, "-c"+compression.Flag(), ".")
return CmdStream(cmd)
}
func Untar(archive io.Reader, path string) error {
cmd := exec.Command("bsdtar", "-f", "-", "-C", path, "-x")
cmd.Stdin = archive
output, err := cmd.CombinedOutput()
if err != nil {
return errors.New(err.Error() + ": " + string(output))
}
return nil
}
// CmdStream executes a command, and returns its stdout as a stream.
// If the command fails to run or doesn't complete successfully, an error
// will be returned, including anything written on stderr.
func CmdStream(cmd *exec.Cmd) (io.Reader, error) {
stdout, err := cmd.StdoutPipe()
if err != nil {
return nil, err
}
stderr, err := cmd.StderrPipe()
if err != nil {
return nil, err
}
pipeR, pipeW := io.Pipe()
errChan := make(chan []byte)
// Collect stderr, we will use it in case of an error
go func() {
errText, e := ioutil.ReadAll(stderr)
if e != nil {
errText = []byte("(...couldn't fetch stderr: " + e.Error() + ")")
}
errChan <- errText
}()
// Copy stdout to the returned pipe
go func() {
_, err := io.Copy(pipeW, stdout)
if err != nil {
pipeW.CloseWithError(err)
}
errText := <-errChan
if err := cmd.Wait(); err != nil {
pipeW.CloseWithError(errors.New(err.Error() + ": " + string(errText)))
} else {
pipeW.Close()
}
}()
// Run the command and return the pipe
if err := cmd.Start(); err != nil {
return nil, err
}
return pipeR, nil
}