Method ContainerAttach

daemon/attach.go:23–96

ContainerAttach attaches to logs according to the config passed in. See ContainerAttachConfig.

(prefixOrName string, req *backend.ContainerAttachConfig)

// ContainerAttach attaches to logs according to the config passed in. See ContainerAttachConfig.
func (daemon *Daemon) ContainerAttach(prefixOrName string, req *backend.ContainerAttachConfig) error {
	keys := []byte{}
	var err error
	if req.DetachKeys != "" {
		keys, err = term.ToBytes(req.DetachKeys)
		if err != nil {
			return errdefs.InvalidParameter(errors.Errorf("Invalid detach keys (%s) provided", req.DetachKeys))
		}
	}

	ctr, err := daemon.GetContainer(prefixOrName)
	if err != nil {
		return err
	}
	if ctr.State.IsPaused() {
		return errdefs.Conflict(fmt.Errorf("container %s is paused, unpause the container before attach", prefixOrName))
	}
	if ctr.State.IsRestarting() {
		return errdefs.Conflict(fmt.Errorf("container %s is restarting, wait until the container is running", prefixOrName))
	}

	cfg := stream.AttachConfig{
		UseStdin:   req.UseStdin,
		UseStdout:  req.UseStdout,
		UseStderr:  req.UseStderr,
		TTY:        ctr.Config.Tty,
		CloseStdin: ctr.Config.StdinOnce,
		DetachKeys: keys,
	}
	ctr.StreamConfig.AttachStreams(&cfg)

	clientCtx, closeNotify := context.WithCancel(context.Background())
	defer closeNotify()
	go func() {
		<-clientCtx.Done()
		// The client has disconnected
		// In this case we need to close the container's output streams so that the goroutines used to copy
		// to the client streams are unblocked and can exit.
		if cfg.CStdout != nil {
			cfg.CStdout.Close()
		}
		if cfg.CStderr != nil {
			cfg.CStderr.Close()
		}
	}()

	multiplexed := !ctr.Config.Tty && req.MuxStreams
	inStream, outStream, errStream, err := req.GetStreams(multiplexed, closeNotify)
	if err != nil {
		return err
	}

	defer inStream.Close()

	if multiplexed {
		errStream = stdcopymux.NewStdWriter(errStream, stdcopy.Stderr)
		outStream = stdcopymux.NewStdWriter(outStream, stdcopy.Stdout)
	}