func postContainerExecCreate(eng *engine.Engine, version version.Version, w http.ResponseWriter, r *http.Request, vars map[string]string) error {
	if err := parseForm(r); err != nil {
		return nil
	}
	var (
		out          engine.Env
		name         = vars["name"]
		job          = eng.Job("execCreate", name)
		stdoutBuffer = bytes.NewBuffer(nil)
	)

	if err := job.DecodeEnv(r.Body); err != nil {
		return err
	}

	job.Stdout.Add(stdoutBuffer)
	// Register an instance of Exec in container.
	if err := job.Run(); err != nil {
		fmt.Fprintf(os.Stderr, "Error setting up exec command in container %s: %s\n", name, err)
		return err
	}
	// Return the ID
	out.Set("Id", engine.Tail(stdoutBuffer, 1))

	return writeJSON(w, http.StatusCreated, out)
}

func waitForExit(cli *DockerCli, containerId string) (int, error) {
	stream, _, err := cli.call("POST", "/containers/"+containerId+"/wait", nil, false)
	if err != nil {
		return -1, err
	}

	var out engine.Env
	if err := out.Decode(stream); err != nil {
		return -1, err
	}
	return out.GetInt("StatusCode"), nil
}

func postContainersWait(eng *engine.Engine, version version.Version, w http.ResponseWriter, r *http.Request, vars map[string]string) error {
	if vars == nil {
		return fmt.Errorf("Missing parameter")
	}
	var (
		env          engine.Env
		stdoutBuffer = bytes.NewBuffer(nil)
		job          = eng.Job("wait", vars["name"])
	)
	job.Stdout.Add(stdoutBuffer)
	if err := job.Run(); err != nil {
		return err
	}

	env.Set("StatusCode", engine.Tail(stdoutBuffer, 1))
	return writeJSON(w, http.StatusOK, env)
}

// getExitCode perform an inspect on the container. It returns
// the running state and the exit code.
func getExitCode(cli *DockerCli, containerId string) (bool, int, error) {
	steam, _, err := cli.call("GET", "/containers/"+containerId+"/json", nil, false)
	if err != nil {
		// If we can't connect, then the daemon probably died.
		if err != ErrConnectionRefused {
			return false, -1, err
		}
		return false, -1, nil
	}

	var result engine.Env
	if err := result.Decode(steam); err != nil {
		return false, -1, err
	}

	state := result.GetSubEnv("State")
	return state.GetBool("Running"), state.GetInt("ExitCode"), nil
}

func postAuth(eng *engine.Engine, version version.Version, w http.ResponseWriter, r *http.Request, vars map[string]string) error {
	var (
		authConfig, err = ioutil.ReadAll(r.Body)
		job             = eng.Job("auth")
		stdoutBuffer    = bytes.NewBuffer(nil)
	)
	if err != nil {
		return err
	}
	job.Setenv("authConfig", string(authConfig))
	job.Stdout.Add(stdoutBuffer)
	if err = job.Run(); err != nil {
		return err
	}
	if status := engine.Tail(stdoutBuffer, 1); status != "" {
		var env engine.Env
		env.Set("Status", status)
		return writeJSON(w, http.StatusOK, env)
	}
	w.WriteHeader(http.StatusNoContent)
	return nil
}

func postContainersCreate(eng *engine.Engine, version version.Version, w http.ResponseWriter, r *http.Request, vars map[string]string) error {
	if err := parseForm(r); err != nil {
		return nil
	}
	var (
		out          engine.Env
		job          = eng.Job("create", r.Form.Get("name"))
		outWarnings  []string
		stdoutBuffer = bytes.NewBuffer(nil)
		warnings     = bytes.NewBuffer(nil)
	)

	if err := checkForJson(r); err != nil {
		return err
	}

	if err := job.DecodeEnv(r.Body); err != nil {
		return err
	}
	// Read container ID from the first line of stdout
	job.Stdout.Add(stdoutBuffer)
	// Read warnings from stderr
	job.Stderr.Add(warnings)
	if err := job.Run(); err != nil {
		return err
	}
	// Parse warnings from stderr
	scanner := bufio.NewScanner(warnings)
	for scanner.Scan() {
		outWarnings = append(outWarnings, scanner.Text())
	}
	out.Set("Id", engine.Tail(stdoutBuffer, 1))
	out.SetList("Warnings", outWarnings)

	return writeJSON(w, http.StatusCreated, out)
}

func postCommit(eng *engine.Engine, version version.Version, w http.ResponseWriter, r *http.Request, vars map[string]string) error {
	if err := parseForm(r); err != nil {
		return err
	}
	var (
		config       engine.Env
		env          engine.Env
		job          = eng.Job("commit", r.Form.Get("container"))
		stdoutBuffer = bytes.NewBuffer(nil)
	)

	if err := checkForJson(r); err != nil {
		return err
	}

	if err := config.Decode(r.Body); err != nil {
		log.Errorf("%s", err)
	}

	if r.FormValue("pause") == "" && version.GreaterThanOrEqualTo("1.13") {
		job.Setenv("pause", "1")
	} else {
		job.Setenv("pause", r.FormValue("pause"))
	}

	job.Setenv("repo", r.Form.Get("repo"))
	job.Setenv("tag", r.Form.Get("tag"))
	job.Setenv("author", r.Form.Get("author"))
	job.Setenv("comment", r.Form.Get("comment"))
	job.SetenvSubEnv("config", &config)

	job.Stdout.Add(stdoutBuffer)
	if err := job.Run(); err != nil {
		return err
	}
	env.Set("Id", engine.Tail(stdoutBuffer, 1))
	return writeJSON(w, http.StatusCreated, env)
}

func writeJSON(w http.ResponseWriter, code int, v engine.Env) error {
	w.Header().Set("Content-Type", "application/json")
	w.WriteHeader(code)
	return v.Encode(w)
}

func postContainersCopy(eng *engine.Engine, version version.Version, w http.ResponseWriter, r *http.Request, vars map[string]string) error {
	if vars == nil {
		return fmt.Errorf("Missing parameter")
	}

	var copyData engine.Env

	if err := checkForJson(r); err != nil {
		return err
	}

	if err := copyData.Decode(r.Body); err != nil {
		return err
	}

	if copyData.Get("Resource") == "" {
		return fmt.Errorf("Path cannot be empty")
	}

	origResource := copyData.Get("Resource")

	if copyData.Get("Resource")[0] == '/' {
		copyData.Set("Resource", copyData.Get("Resource")[1:])
	}

	job := eng.Job("container_copy", vars["name"], copyData.Get("Resource"))
	job.Stdout.Add(w)
	w.Header().Set("Content-Type", "application/x-tar")
	if err := job.Run(); err != nil {
		log.Errorf("%s", err.Error())
		if strings.Contains(strings.ToLower(err.Error()), "no such container") {
			w.WriteHeader(http.StatusNotFound)
		} else if strings.Contains(err.Error(), "no such file or directory") {
			return fmt.Errorf("Could not find the file %s in container %s", origResource, vars["name"])
		}
	}
	return nil
}