124 lines
2.7 KiB
Go
124 lines
2.7 KiB
Go
package docker
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import (
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"errors"
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"io"
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"io/ioutil"
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"os"
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"os/exec"
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)
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type Archive io.Reader
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type Compression uint32
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const (
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Uncompressed Compression = iota
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Bzip2
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Gzip
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Xz
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)
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func (compression *Compression) Flag() string {
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switch *compression {
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case Bzip2:
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return "j"
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case Gzip:
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return "z"
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case Xz:
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return "J"
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}
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return ""
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}
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func Tar(path string, compression Compression) (io.Reader, error) {
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cmd := exec.Command("bsdtar", "-f", "-", "-C", path, "-c"+compression.Flag(), ".")
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return CmdStream(cmd)
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}
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func Untar(archive io.Reader, path string) error {
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cmd := exec.Command("bsdtar", "-f", "-", "-C", path, "-x")
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cmd.Stdin = archive
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output, err := cmd.CombinedOutput()
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if err != nil {
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return errors.New(err.Error() + ": " + string(output))
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}
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return nil
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}
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// CmdStream executes a command, and returns its stdout as a stream.
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// If the command fails to run or doesn't complete successfully, an error
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// will be returned, including anything written on stderr.
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func CmdStream(cmd *exec.Cmd) (io.Reader, error) {
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stdout, err := cmd.StdoutPipe()
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if err != nil {
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return nil, err
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}
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stderr, err := cmd.StderrPipe()
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if err != nil {
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return nil, err
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}
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pipeR, pipeW := io.Pipe()
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errChan := make(chan []byte)
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// Collect stderr, we will use it in case of an error
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go func() {
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errText, e := ioutil.ReadAll(stderr)
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if e != nil {
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errText = []byte("(...couldn't fetch stderr: " + e.Error() + ")")
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}
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errChan <- errText
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}()
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// Copy stdout to the returned pipe
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go func() {
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_, err := io.Copy(pipeW, stdout)
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if err != nil {
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pipeW.CloseWithError(err)
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}
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errText := <-errChan
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if err := cmd.Wait(); err != nil {
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pipeW.CloseWithError(errors.New(err.Error() + ": " + string(errText)))
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} else {
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pipeW.Close()
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}
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}()
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// Run the command and return the pipe
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if err := cmd.Start(); err != nil {
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return nil, err
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}
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return pipeR, nil
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}
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// NewTempArchive reads the content of src into a temporary file, and returns the contents
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// of that file as an archive. The archive can only be read once - as soon as reading completes,
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// the file will be deleted.
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func NewTempArchive(src Archive, dir string) (*TempArchive, error) {
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f, err := ioutil.TempFile(dir, "")
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if err != nil {
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return nil, err
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}
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if _, err := io.Copy(f, src); err != nil {
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return nil, err
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}
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if _, err := f.Seek(0, 0); err != nil {
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return nil, err
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}
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st, err := f.Stat()
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if err != nil {
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return nil, err
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}
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size := st.Size()
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return &TempArchive{f, size}, nil
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}
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type TempArchive struct {
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*os.File
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Size int64 // Pre-computed from Stat().Size() as a convenience
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}
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func (archive *TempArchive) Read(data []byte) (int, error) {
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n, err := archive.File.Read(data)
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if err != nil {
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os.Remove(archive.File.Name())
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}
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return n, err
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}
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