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 (
		name         = vars["name"]
		job          = eng.Job("execCreate", name)
		stdoutBuffer = bytes.NewBuffer(nil)
		outWarnings  []string
		warnings     = bytes.NewBuffer(nil)
	)

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

	job.Stdout.Add(stdoutBuffer)
	// Read warnings from stderr
	job.Stderr.Add(warnings)
	// 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
	}
	// Parse warnings from stderr
	scanner := bufio.NewScanner(warnings)
	for scanner.Scan() {
		outWarnings = append(outWarnings, scanner.Text())
	}

	return writeJSON(w, http.StatusCreated, &types.ContainerExecCreateResponse{
		ID:       engine.Tail(stdoutBuffer, 1),
		Warnings: outWarnings,
	})
}

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 := 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)
}

// Install installs daemon capabilities to eng.
func (daemon *Daemon) Install(eng *engine.Engine) error {
	for name, method := range map[string]engine.Handler{
		"container_inspect": daemon.ContainerInspect,
		"create":            daemon.ContainerCreate,
		"info":              daemon.CmdInfo,
		"restart":           daemon.ContainerRestart,
		"start":             daemon.ContainerStart,
		"execCreate":        daemon.ContainerExecCreate,
		"execStart":         daemon.ContainerExecStart,
	} {
		if err := eng.Register(name, method); err != nil {
			return err
		}
	}
	if err := daemon.Repositories().Install(eng); err != nil {
		return err
	}
	if err := daemon.trustStore.Install(eng); err != nil {
		return err
	}
	// FIXME: this hack is necessary for legacy integration tests to access
	// the daemon object.
	eng.HackSetGlobalVar("httpapi.daemon", daemon)
	return nil
}

func postContainersStart(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 (
		name = vars["name"]
		job  = eng.Job("start", name)
	)

	// allow a nil body for backwards compatibility
	if r.Body != nil && r.ContentLength > 0 {
		if !api.MatchesContentType(r.Header.Get("Content-Type"), "application/json") {
			return fmt.Errorf("Content-Type of application/json is required")
		}

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

	if err := job.Run(); err != nil {
		if err.Error() == "Container already started" {
			w.WriteHeader(http.StatusNotModified)
			return nil
		}
		return err
	}
	w.WriteHeader(http.StatusNoContent)
	return nil
}

func postContainersStart(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 (
		name = vars["name"]
		job  = eng.Job("start", name)
	)

	// If contentLength is -1, we can assumed chunked encoding
	// or more technically that the length is unknown
	// http://golang.org/src/pkg/net/http/request.go#L139
	// net/http otherwise seems to swallow any headers related to chunked encoding
	// including r.TransferEncoding
	// allow a nil body for backwards compatibility
	if r.Body != nil && (r.ContentLength > 0 || r.ContentLength == -1) {
		if err := checkForJson(r); err != nil {
			return err
		}

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

	if err := job.Run(); err != nil {
		if err.Error() == "Container already started" {
			w.WriteHeader(http.StatusNotModified)
			return nil
		}
		return err
	}
	w.WriteHeader(http.StatusNoContent)
	return nil
}

// Creates an image from Pull or from Import
func postImagesCreate(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 (
		image = r.Form.Get("fromImage")
		repo  = r.Form.Get("repo")
		tag   = r.Form.Get("tag")
		job   *engine.Job
	)
	authEncoded := r.Header.Get("X-Registry-Auth")
	authConfig := &registry.AuthConfig{}
	if authEncoded != "" {
		authJson := base64.NewDecoder(base64.URLEncoding, strings.NewReader(authEncoded))
		if err := json.NewDecoder(authJson).Decode(authConfig); err != nil {
			// for a pull it is not an error if no auth was given
			// to increase compatibility with the existing api it is defaulting to be empty
			authConfig = &registry.AuthConfig{}
		}
	}
	if image != "" { //pull
		if tag == "" {
			image, tag = parsers.ParseRepositoryTag(image)
		}
		metaHeaders := map[string][]string{}
		for k, v := range r.Header {
			if strings.HasPrefix(k, "X-Meta-") {
				metaHeaders[k] = v
			}
		}
		job = eng.Job("pull", image, tag)
		job.SetenvBool("parallel", version.GreaterThan("1.3"))
		job.SetenvJson("metaHeaders", metaHeaders)
		job.SetenvJson("authConfig", authConfig)
	} else { //import
		if tag == "" {
			repo, tag = parsers.ParseRepositoryTag(repo)
		}
		job = eng.Job("import", r.Form.Get("fromSrc"), repo, tag)
		job.Stdin.Add(r.Body)
		job.SetenvList("changes", r.Form["changes"])
	}

	if version.GreaterThan("1.0") {
		job.SetenvBool("json", true)
		streamJSON(job, w, true)
	} else {
		job.Stdout.Add(utils.NewWriteFlusher(w))
	}
	if err := job.Run(); err != nil {
		if !job.Stdout.Used() {
			return err
		}
		sf := utils.NewStreamFormatter(version.GreaterThan("1.0"))
		w.Write(sf.FormatError(err))
	}

	return nil
}

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 getImagesSearch(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 (
		authEncoded = r.Header.Get("X-Registry-Auth")
		authConfig  = &registry.AuthConfig{}
		metaHeaders = map[string][]string{}
	)

	if authEncoded != "" {
		authJson := base64.NewDecoder(base64.URLEncoding, strings.NewReader(authEncoded))
		if err := json.NewDecoder(authJson).Decode(authConfig); err != nil {
			// for a search it is not an error if no auth was given
			// to increase compatibility with the existing api it is defaulting to be empty
			authConfig = &registry.AuthConfig{}
		}
	}
	for k, v := range r.Header {
		if strings.HasPrefix(k, "X-Meta-") {
			metaHeaders[k] = v
		}
	}

	var job = eng.Job("search", r.Form.Get("term"))
	job.SetenvJson("metaHeaders", metaHeaders)
	job.SetenvJson("authConfig", authConfig)
	streamJSON(job, w, false)

	return job.Run()
}

func deleteContainers(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
	}
	if vars == nil {
		return fmt.Errorf("Missing parameter")
	}
	job := eng.Job("container_delete", vars["name"])

	if version.GreaterThanOrEqualTo("1.14") {
		job.Setenv("stop", r.Form.Get("stop"))
		job.Setenv("kill", r.Form.Get("kill"))

		if job.GetenvBool("stop") && job.GetenvBool("kill") {
			return fmt.Errorf("Bad parameters: can't use stop and kill simultaneously")
		}
	} else {
		job.Setenv("stop", r.Form.Get("force"))
	}
	job.Setenv("removeVolume", r.Form.Get("v"))
	job.Setenv("removeLink", r.Form.Get("link"))
	if err := job.Run(); err != nil {
		return err
	}
	w.WriteHeader(http.StatusNoContent)
	return nil
}

func postContainersResize(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
	}
	if vars == nil {
		return fmt.Errorf("Missing parameter")
	}

	var (
		job    = eng.Job("container_inspect", vars["name"])
		c, err = job.Stdout.AddEnv()
	)
	if err != nil {
		return err
	}
	if err = job.Run(); err != nil {
		return err
	}

	monitorDriver := c.Get("MonitorDriver")
	if monitorDriver == daemon.MonitorExternal {
		Id := c.Get("Id")
		// Redirect to monitor socket
		return fmt.Errorf("redirect to:%s", fmt.Sprintf("unix://%s/%s.sock", daemon.MonitorSockDir, Id))
	}

	if err = eng.Job("resize", vars["name"], r.Form.Get("h"), r.Form.Get("w")).Run(); err != nil {
		return err
	}
	return nil
}

func postContainersSet(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 (
		setData engine.Env
		config  []struct {
			Key   string
			Value string
		}
	)
	if contentType := r.Header.Get("Content-Type"); api.MatchesContentType(contentType, "application/json") {
		if err := setData.Decode(r.Body); err != nil {
			return err
		}
	} else {
		return fmt.Errorf("Content-Type not supported: %s", contentType)
	}

	if err := setData.GetJson("config", &config); err != nil {
		return err
	}
	job := eng.Job("container_set", vars["name"])
	job.SetenvJson("config", config)

	job.Stdout.Add(w)
	if err := job.Run(); err != nil {
		return err
	}

	return nil
}

func (s *TagStore) recursiveLoad(eng *engine.Engine, address, tmpImageDir string) error {
	if err := eng.Job("image_get", address).Run(); err != nil {
		log.Debugf("Loading %s", address)

		imageJson, err := ioutil.ReadFile(path.Join(tmpImageDir, "repo", address, "json"))
		if err != nil {
			log.Debugf("Error reading json", err)
			return err
		}

		layer, err := os.Open(path.Join(tmpImageDir, "repo", address, "layer.tar"))
		if err != nil {
			log.Debugf("Error reading embedded tar", err)
			return err
		}
		img, err := image.NewImgJSON(imageJson)
		if err != nil {
			log.Debugf("Error unmarshalling json", err)
			return err
		}
		if img.Parent != "" {
			if !s.graph.Exists(img.Parent) {
				if err := s.recursiveLoad(eng, img.Parent, tmpImageDir); err != nil {
					return err
				}
			}
		}
		if err := s.graph.Register(img, imageJson, layer); err != nil {
			return err
		}
	}
	log.Debugf("Completed processing %s", address)

	return nil
}

func wsContainersAttach(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
	}
	if vars == nil {
		return fmt.Errorf("Missing parameter")
	}

	if err := eng.Job("container_inspect", vars["name"]).Run(); err != nil {
		return err
	}

	h := websocket.Handler(func(ws *websocket.Conn) {
		defer ws.Close()
		job := eng.Job("attach", vars["name"])
		job.Setenv("logs", r.Form.Get("logs"))
		job.Setenv("stream", r.Form.Get("stream"))
		job.Setenv("stdin", r.Form.Get("stdin"))
		job.Setenv("stdout", r.Form.Get("stdout"))
		job.Setenv("stderr", r.Form.Get("stderr"))
		job.Stdin.Add(ws)
		job.Stdout.Add(ws)
		job.Stderr.Set(ws)
		if err := job.Run(); err != nil {
			utils.Errorf("Error attaching websocket: %s", err)
		}
	})
	h.ServeHTTP(w, r)

	return nil
}

func (container *Container) allocatePort(eng *engine.Engine, port nat.Port, bindings nat.PortMap) error {
	binding := bindings[port]
	if container.hostConfig.PublishAllPorts && len(binding) == 0 {
		binding = append(binding, nat.PortBinding{})
	}

	for i := 0; i < len(binding); i++ {
		b := binding[i]

		job := eng.Job("allocate_port", container.ID)
		job.Setenv("HostIP", b.HostIp)
		job.Setenv("HostPort", b.HostPort)
		job.Setenv("Proto", port.Proto())
		job.Setenv("ContainerPort", port.Port())

		portEnv, err := job.Stdout.AddEnv()
		if err != nil {
			return err
		}
		if err := job.Run(); err != nil {
			eng.Job("release_interface", container.ID).Run()
			return err
		}
		b.HostIp = portEnv.Get("HostIP")
		b.HostPort = portEnv.Get("HostPort")

		binding[i] = b
	}
	bindings[port] = binding
	return nil
}

// Create a test container, start it, wait for it to complete, destroy it,
// and return its standard output as a string.
// The image name (eg. the XXX in []string{"-i", "-t", "XXX", "bash"}, is dynamically replaced by the current test image.
// If t is not nil, call t.Fatal() at the first error. Otherwise return errors normally.
func runContainer(eng *engine.Engine, r *daemon.Daemon, args []string, t *testing.T) (output string, err error) {
	defer func() {
		if err != nil && t != nil {
			t.Fatal(err)
		}
	}()
	container, hc, err := mkContainer(r, args, t)
	if err != nil {
		return "", err
	}
	defer r.Destroy(container)
	stdout, err := container.StdoutPipe()
	if err != nil {
		return "", err
	}
	defer stdout.Close()

	job := eng.Job("start", container.ID)
	if err := job.ImportEnv(hc); err != nil {
		return "", err
	}
	if err := job.Run(); err != nil {
		return "", err
	}

	container.WaitStop(-1 * time.Second)
	data, err := ioutil.ReadAll(stdout)
	if err != nil {
		return "", err
	}
	output = string(data)
	return
}

// Install installs daemon capabilities to eng.
func (daemon *Daemon) Install(eng *engine.Engine) error {
	// FIXME: rename "delete" to "rm" for consistency with the CLI command
	// FIXME: rename ContainerDestroy to ContainerRm for consistency with the CLI command
	// FIXME: remove ImageDelete's dependency on Daemon, then move to graph/
	for name, method := range map[string]engine.Handler{
		"attach":            daemon.ContainerAttach,
		"commit":            daemon.ContainerCommit,
		"container_changes": daemon.ContainerChanges,
		"container_copy":    daemon.ContainerCopy,
		"container_inspect": daemon.ContainerInspect,
		"containers":        daemon.Containers,
		"create":            daemon.ContainerCreate,
		"delete":            daemon.ContainerDestroy,
		"export":            daemon.ContainerExport,
		"kill":              daemon.ContainerKill,
		"logs":              daemon.ContainerLogs,
		"pause":             daemon.ContainerPause,
		"resize":            daemon.ContainerResize,
		"restart":           daemon.ContainerRestart,
		"start":             daemon.ContainerStart,
		"stop":              daemon.ContainerStop,
		"top":               daemon.ContainerTop,
		"unpause":           daemon.ContainerUnpause,
		"wait":              daemon.ContainerWait,
		"image_delete":      daemon.ImageDelete, // FIXME: see above
	} {
		if err := eng.Register(name, method); err != nil {
			return err
		}
	}
	return nil
}

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 := config.Decode(r.Body); err != nil {
		utils.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 (s *TagStore) Install(eng *engine.Engine) error {
	for name, handler := range map[string]engine.Handler{
		"image_set":      s.CmdSet,
		"image_tag":      s.CmdTag,
		"tag":            s.CmdTagLegacy, // FIXME merge with "image_tag"
		"image_get":      s.CmdGet,
		"image_inspect":  s.CmdLookup,
		"image_tarlayer": s.CmdTarLayer,
		"image_export":   s.CmdImageExport,
		"apply_pull":     s.CmdPullAndApply,
		"apply_diff":     s.CmdDiffAndApply,
		"history":        s.CmdHistory,
		"images":         s.CmdImages,
		"viz":            s.CmdViz,
		"load":           s.CmdLoad,
		"import":         s.CmdImport,
		"pull":           s.CmdPull,
		"push":           s.CmdPush,
	} {
		if err := eng.Register(name, handler); err != nil {
			return fmt.Errorf("Could not register %q: %v", name, err)
		}
	}
	return nil
}

// TODO(vishh): Refactor the code to avoid having to specify stream config as part of both create and start.
func postContainerExecStart(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 (
		name             = vars["name"]
		job              = eng.Job("execStart", name)
		errOut io.Writer = os.Stderr
	)

	if err := job.DecodeEnv(r.Body); err != nil {
		return err
	}
	if !job.GetenvBool("Detach") {
		// Setting up the streaming http interface.
		inStream, outStream, err := hijackServer(w)
		if err != nil {
			return err
		}

		defer func() {
			if tcpc, ok := inStream.(*net.TCPConn); ok {
				tcpc.CloseWrite()
			} else {
				inStream.Close()
			}
		}()
		defer func() {
			if tcpc, ok := outStream.(*net.TCPConn); ok {
				tcpc.CloseWrite()
			} else if closer, ok := outStream.(io.Closer); ok {
				closer.Close()
			}
		}()

		var errStream io.Writer

		fmt.Fprintf(outStream, "HTTP/1.1 200 OK\r\nContent-Type: application/vnd.docker.raw-stream\r\n\r\n")
		if !job.GetenvBool("Tty") && version.GreaterThanOrEqualTo("1.6") {
			errStream = stdcopy.NewStdWriter(outStream, stdcopy.Stderr)
			outStream = stdcopy.NewStdWriter(outStream, stdcopy.Stdout)
		} else {
			errStream = outStream
		}
		job.Stdin.Add(inStream)
		job.Stdout.Add(outStream)
		job.Stderr.Set(errStream)
		errOut = outStream
	}
	// Now run the user process in container.
	job.SetCloseIO(false)
	if err := job.Run(); err != nil {
		fmt.Fprintf(errOut, "Error starting exec command in container %s: %s\n", name, err)
		return err
	}
	w.WriteHeader(http.StatusNoContent)

	return nil
}

func getImagesViz(eng *engine.Engine, version version.Version, w http.ResponseWriter, r *http.Request, vars map[string]string) error {
	if version.GreaterThan("1.6") {
		w.WriteHeader(http.StatusNotFound)
		return fmt.Errorf("This is now implemented in the client.")
	}
	eng.ServeHTTP(w, r)
	return nil
}