container: fix Logs behavior

Docker sends the output in the following format:

	<header identifying the stream and with the size fo the frame>
	<frame>

It allows us to multiplex the content between the output and error
streams.

I wondering whether I should rewrite the StdCopy function, it's a little
messy.

Related to #114.

client.go

@@ -280,11 +280,10 @@ func (c *Client) do(method, path string, data interface{}) ([]byte, int, error)
 	return body, resp.StatusCode, nil
 }
 
-func (c *Client) stream(method, path string, headers map[string]string, in io.Reader, out io.Writer) error {
+func (c *Client) stream(method, path string, setRawTerminal bool, headers map[string]string, in io.Reader, stdout, stderr io.Writer) error {
 	if (method == "POST" || method == "PUT") && in == nil {
 		in = bytes.NewReader(nil)
 	}
-
 	if path != "/version" && !c.SkipServerVersionCheck && c.expectedApiVersion == nil {
 		err := c.checkApiVersion()
 		if err != nil {
@@ -305,8 +304,11 @@ func (c *Client) stream(method, path string, headers map[string]string, in io.Re
 	var resp *http.Response
 	protocol := c.endpointURL.Scheme
 	address := c.endpointURL.Path
-	if out == nil {
-		out = ioutil.Discard
+	if stdout == nil {
+		stdout = ioutil.Discard
+	}
+	if stderr == nil {
+		stderr = ioutil.Discard
 	}
 	if protocol == "unix" {
 		dial, err := net.Dial(protocol, address)
@@ -343,20 +345,23 @@ func (c *Client) stream(method, path string, headers map[string]string, in io.Re
 				return err
 			}
 			if m.Stream != "" {
-				fmt.Fprint(out, m.Stream)
+				fmt.Fprint(stdout, m.Stream)
 			} else if m.Progress != "" {
-				fmt.Fprintf(out, "%s %s\r", m.Status, m.Progress)
+				fmt.Fprintf(stdout, "%s %s\r", m.Status, m.Progress)
 			} else if m.Error != "" {
 				return errors.New(m.Error)
 			}
 			if m.Status != "" {
-				fmt.Fprintln(out, m.Status)
+				fmt.Fprintln(stdout, m.Status)
 			}
 		}
 	} else {
-		if _, err := io.Copy(out, resp.Body); err != nil {
-			return err
+		if setRawTerminal {
+			_, err = io.Copy(stdout, resp.Body)
+		} else {
+			_, err = utils.StdCopy(stdout, stderr, resp.Body)
 		}
+		return err
 	}
 	return nil
 }

container.go

@@ -568,11 +568,15 @@ func (c *Client) AttachToContainer(opts AttachToContainerOptions) error {
 type LogsOptions struct {
 	Container    string    `qs:"-"`
 	OutputStream io.Writer `qs:"-"`
+	ErrorStream  io.Writer `qs:"-"`
 	Follow       bool
 	Stdout       bool
 	Stderr       bool
 	Timestamps   bool
 	Tail         string
+
+	// Use raw terminal? Usually true when the container contains a TTY.
+	RawTerminal bool `qs:"-"`
 }
 
 // Logs gets stdout and stderr logs from the specified container.
@@ -586,7 +590,7 @@ func (c *Client) Logs(opts LogsOptions) error {
 		opts.Tail = "all"
 	}
 	path := "/containers/" + opts.Container + "/logs?" + queryString(opts)
-	return c.stream("GET", path, nil, nil, opts.OutputStream)
+	return c.stream("GET", path, opts.RawTerminal, nil, nil, opts.OutputStream, opts.ErrorStream)
 }
 
 // ResizeContainerTTY resizes the terminal to the given height and width.
@@ -616,7 +620,7 @@ func (c *Client) ExportContainer(opts ExportContainerOptions) error {
 		return NoSuchContainer{ID: opts.ID}
 	}
 	url := fmt.Sprintf("/containers/%s/export", opts.ID)
-	return c.stream("GET", url, nil, nil, opts.OutputStream)
+	return c.stream("GET", url, true, nil, nil, opts.OutputStream, nil)
 }
 
 // NoSuchContainer is the error returned when a given container does not exist.

container_test.go

@@ -912,6 +912,8 @@ func TestAttachToContainerWithoutContainer(t *testing.T) {
 func TestLogs(t *testing.T) {
 	var req http.Request
 	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		prefix := []byte{1, 0, 0, 0, 0, 0, 0, 19}
+		w.Write(prefix)
 		w.Write([]byte("something happened!"))
 		req = *r
 	}))
@@ -958,6 +960,8 @@ func TestLogs(t *testing.T) {
 func TestLogsSpecifyingTail(t *testing.T) {
 	var req http.Request
 	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		prefix := []byte{1, 0, 0, 0, 0, 0, 0, 19}
+		w.Write(prefix)
 		w.Write([]byte("something happened!"))
 		req = *r
 	}))
@@ -1002,6 +1006,36 @@ func TestLogsSpecifyingTail(t *testing.T) {
 	}
 }
 
+func TestLogsRawTerminal(t *testing.T) {
+	var req http.Request
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Write([]byte("something happened!"))
+		req = *r
+	}))
+	defer server.Close()
+	client, _ := NewClient(server.URL)
+	client.SkipServerVersionCheck = true
+	var buf bytes.Buffer
+	opts := LogsOptions{
+		Container:    "a123456",
+		OutputStream: &buf,
+		Follow:       true,
+		RawTerminal:  true,
+		Stdout:       true,
+		Stderr:       true,
+		Timestamps:   true,
+		Tail:         "100",
+	}
+	err := client.Logs(opts)
+	if err != nil {
+		t.Fatal(err)
+	}
+	expected := "something happened!"
+	if buf.String() != expected {
+		t.Errorf("Logs: wrong output. Want %q. Got %q.", expected, buf.String())
+	}
+}
+
 func TestLogsNoContainer(t *testing.T) {
 	var client Client
 	err := client.Logs(LogsOptions{})

image.go

@@ -187,7 +187,7 @@ func (c *Client) PushImage(opts PushImageOptions, auth AuthConfiguration) error
 
 	headers["X-Registry-Auth"] = base64.URLEncoding.EncodeToString(buf.Bytes())
 
-	return c.stream("POST", path, headers, nil, opts.OutputStream)
+	return c.stream("POST", path, true, headers, nil, opts.OutputStream, nil)
 }
 
 // PullImageOptions present the set of options available for pulling an image
@@ -219,7 +219,7 @@ func (c *Client) PullImage(opts PullImageOptions, auth AuthConfiguration) error
 
 func (c *Client) createImage(qs string, headers map[string]string, in io.Reader, w io.Writer) error {
 	path := "/images/create?" + qs
-	return c.stream("POST", path, headers, in, w)
+	return c.stream("POST", path, true, headers, in, w, nil)
 }
 
 // ImportImageOptions present the set of informations available for importing
@@ -286,7 +286,7 @@ func (c *Client) BuildImage(opts BuildImageOptions) error {
 		return ErrMissingRepo
 	}
 	return c.stream("POST", fmt.Sprintf("/build?%s",
-		queryString(&opts)), headers, opts.InputStream, opts.OutputStream)
+		queryString(&opts)), true, headers, opts.InputStream, opts.OutputStream, nil)
 }
 
 // TagImageOptions present the set of options to tag an image