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- package docker
- import (
- "bytes"
- "container/list"
- "io"
- "os"
- "os/exec"
- "path/filepath"
- "sync"
- )
- func Trunc(s string, maxlen int) string {
- if len(s) <= maxlen {
- return s
- }
- return s[:maxlen]
- }
- // Tar generates a tar archive from a filesystem path, and returns it as a stream.
- // Path must point to a directory.
- func Tar(path string) (io.Reader, error) {
- cmd := exec.Command("tar", "-C", path, "-c", ".")
- output, err := cmd.StdoutPipe()
- if err != nil {
- return nil, err
- }
- if err := cmd.Start(); err != nil {
- return nil, err
- }
- // FIXME: errors will not be passed because we don't wait for the command.
- // Instead, consumers will hit EOF right away.
- // This can be fixed by waiting for the process to exit, or for the first write
- // on stdout, whichever comes first.
- return output, nil
- }
- // Figure out the absolute path of our own binary
- func SelfPath() string {
- path, err := exec.LookPath(os.Args[0])
- if err != nil {
- panic(err)
- }
- path, err = filepath.Abs(path)
- if err != nil {
- panic(err)
- }
- return path
- }
- type nopWriteCloser struct {
- io.Writer
- }
- func (w *nopWriteCloser) Close() error { return nil }
- func NopWriteCloser(w io.Writer) io.WriteCloser {
- return &nopWriteCloser{w}
- }
- type bufReader struct {
- buf *bytes.Buffer
- reader io.Reader
- err error
- l sync.Mutex
- wait sync.Cond
- }
- func newBufReader(r io.Reader) *bufReader {
- reader := &bufReader{
- buf: &bytes.Buffer{},
- reader: r,
- }
- reader.wait.L = &reader.l
- go reader.drain()
- return reader
- }
- func (r *bufReader) drain() {
- buf := make([]byte, 1024)
- for {
- n, err := r.reader.Read(buf)
- if err != nil {
- r.err = err
- } else {
- r.buf.Write(buf[0:n])
- }
- r.l.Lock()
- r.wait.Signal()
- r.l.Unlock()
- if err != nil {
- break
- }
- }
- }
- func (r *bufReader) Read(p []byte) (n int, err error) {
- for {
- n, err = r.buf.Read(p)
- if n > 0 {
- return n, err
- }
- if r.err != nil {
- return 0, r.err
- }
- r.l.Lock()
- r.wait.Wait()
- r.l.Unlock()
- }
- return
- }
- func (r *bufReader) Close() error {
- closer, ok := r.reader.(io.ReadCloser)
- if !ok {
- return nil
- }
- return closer.Close()
- }
- type writeBroadcaster struct {
- writers *list.List
- }
- func (w *writeBroadcaster) AddWriter(writer io.WriteCloser) {
- w.writers.PushBack(writer)
- }
- func (w *writeBroadcaster) RemoveWriter(writer io.WriteCloser) {
- for e := w.writers.Front(); e != nil; e = e.Next() {
- v := e.Value.(io.Writer)
- if v == writer {
- w.writers.Remove(e)
- return
- }
- }
- }
- func (w *writeBroadcaster) Write(p []byte) (n int, err error) {
- failed := []*list.Element{}
- for e := w.writers.Front(); e != nil; e = e.Next() {
- writer := e.Value.(io.Writer)
- if n, err := writer.Write(p); err != nil || n != len(p) {
- // On error, evict the writer
- failed = append(failed, e)
- }
- }
- // We cannot remove while iterating, so it has to be done in
- // a separate step
- for _, e := range failed {
- w.writers.Remove(e)
- }
- return len(p), nil
- }
- func (w *writeBroadcaster) Close() error {
- for e := w.writers.Front(); e != nil; e = e.Next() {
- writer := e.Value.(io.WriteCloser)
- writer.Close()
- }
- return nil
- }
- func newWriteBroadcaster() *writeBroadcaster {
- return &writeBroadcaster{list.New()}
- }
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