Example #1
0
// 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, input io.Reader) (io.ReadCloser, <-chan struct{}, error) {
	chdone := make(chan struct{})
	cmd.Stdin = input
	pipeR, pipeW := io.Pipe()
	cmd.Stdout = pipeW
	var errBuf bytes.Buffer
	cmd.Stderr = &errBuf

	// Run the command and return the pipe
	if err := cmd.Start(); err != nil {
		return nil, nil, err
	}

	// Copy stdout to the returned pipe
	go func() {
		if err := cmd.Wait(); err != nil {
			pipeW.CloseWithError(fmt.Errorf("%s: %s", err, errBuf.String()))
		} else {
			pipeW.Close()
		}
		close(chdone)
	}()

	return pipeR, chdone, nil
}
Example #2
0
func (p *process) startCmd(cmd *exec.Cmd) error {
	if err := cmd.Start(); err != nil {
		if exErr, ok := err.(*exec.Error); ok {
			if exErr.Err == exec.ErrNotFound || exErr.Err == os.ErrNotExist {
				return fmt.Errorf("%s not installed on system", p.container.shim)
			}
		}
		return err
	}
	if err := p.waitForStart(cmd); err != nil {
		return err
	}
	return nil
}