Merge pull request #1842 from dotcloud/split_stdout_stderr

* Runtime: Split stdout stderr

api.go

@@ -21,10 +21,12 @@ import (
 	"strings"
 )
 
-const APIVERSION = 1.5
-const DEFAULTHTTPHOST = "127.0.0.1"
-const DEFAULTHTTPPORT = 4243
-const DEFAULTUNIXSOCKET = "/var/run/docker.sock"
+const (
+	APIVERSION        = 1.6
+	DEFAULTHTTPHOST   = "127.0.0.1"
+	DEFAULTHTTPPORT   = 4243
+	DEFAULTUNIXSOCKET = "/var/run/docker.sock"
+)
 
 type HttpApiFunc func(srv *Server, version float64, w http.ResponseWriter, r *http.Request, vars map[string]string) error
 
@@ -710,32 +712,43 @@ func postContainersAttach(srv *Server, version float64, w http.ResponseWriter, r
 	}
 	name := vars["name"]
 
-	if _, err := srv.ContainerInspect(name); err != nil {
+	c, err := srv.ContainerInspect(name)
+	if err != nil {
 		return err
 	}
 
-	in, out, err := hijackServer(w)
+	inStream, outStream, err := hijackServer(w)
 	if err != nil {
 		return err
 	}
 	defer func() {
-		if tcpc, ok := in.(*net.TCPConn); ok {
+		if tcpc, ok := inStream.(*net.TCPConn); ok {
 			tcpc.CloseWrite()
 		} else {
-			in.Close()
+			inStream.Close()
 		}
 	}()
 	defer func() {
-		if tcpc, ok := out.(*net.TCPConn); ok {
+		if tcpc, ok := outStream.(*net.TCPConn); ok {
 			tcpc.CloseWrite()
-		} else if closer, ok := out.(io.Closer); ok {
+		} else if closer, ok := outStream.(io.Closer); ok {
 			closer.Close()
 		}
 	}()
 
-	fmt.Fprintf(out, "HTTP/1.1 200 OK\r\nContent-Type: application/vnd.docker.raw-stream\r\n\r\n")
-	if err := srv.ContainerAttach(name, logs, stream, stdin, stdout, stderr, in, out); err != nil {
-		fmt.Fprintf(out, "Error: %s\n", err)
+	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 !c.Config.Tty && version >= 1.6 {
+		errStream = utils.NewStdWriter(outStream, utils.Stderr)
+		outStream = utils.NewStdWriter(outStream, utils.Stdout)
+	} else {
+		errStream = outStream
+	}
+
+	if err := srv.ContainerAttach(name, logs, stream, stdin, stdout, stderr, inStream, outStream, errStream); err != nil {
+		fmt.Fprintf(outStream, "Error: %s\n", err)
 	}
 	return nil
 }
@@ -778,7 +791,7 @@ func wsContainersAttach(srv *Server, version float64, w http.ResponseWriter, r *
 	h := websocket.Handler(func(ws *websocket.Conn) {
 		defer ws.Close()
 
-		if err := srv.ContainerAttach(name, logs, stream, stdin, stdout, stderr, ws, ws); err != nil {
+		if err := srv.ContainerAttach(name, logs, stream, stdin, stdout, stderr, ws, ws, ws); err != nil {
 			utils.Debugf("Error: %s", err)
 		}
 	})

api_test.go

@@ -566,7 +566,6 @@ func TestPostCommit(t *testing.T) {
 
 	srv := &Server{runtime: runtime}
 
-
 	// Create a container and remove a file
 	container, err := runtime.Create(
 		&Config{
@@ -952,7 +951,96 @@ func TestPostContainersAttach(t *testing.T) {
 	})
 
 	setTimeout(t, "read/write assertion timed out", 2*time.Second, func() {
-		if err := assertPipe("hello\n", "hello", stdout, stdinPipe, 15); err != nil {
+		if err := assertPipe("hello\n", string([]byte{1, 0, 0, 0, 0, 0, 0, 6})+"hello", stdout, stdinPipe, 15); err != nil {
+			t.Fatal(err)
+		}
+	})
+
+	// Close pipes (client disconnects)
+	if err := closeWrap(stdin, stdinPipe, stdout, stdoutPipe); err != nil {
+		t.Fatal(err)
+	}
+
+	// Wait for attach to finish, the client disconnected, therefore, Attach finished his job
+	setTimeout(t, "Waiting for CmdAttach timed out", 10*time.Second, func() {
+		<-c1
+	})
+
+	// We closed stdin, expect /bin/cat to still be running
+	// Wait a little bit to make sure container.monitor() did his thing
+	err = container.WaitTimeout(500 * time.Millisecond)
+	if err == nil || !container.State.Running {
+		t.Fatalf("/bin/cat is not running after closing stdin")
+	}
+
+	// Try to avoid the timeout in destroy. Best effort, don't check error
+	cStdin, _ := container.StdinPipe()
+	cStdin.Close()
+	container.Wait()
+}
+
+func TestPostContainersAttachStderr(t *testing.T) {
+	runtime := mkRuntime(t)
+	defer nuke(runtime)
+
+	srv := &Server{runtime: runtime}
+
+	container, err := runtime.Create(
+		&Config{
+			Image:     GetTestImage(runtime).ID,
+			Cmd:       []string{"/bin/sh", "-c", "/bin/cat >&2"},
+			OpenStdin: true,
+		},
+	)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer runtime.Destroy(container)
+
+	// Start the process
+	hostConfig := &HostConfig{}
+	if err := container.Start(hostConfig); err != nil {
+		t.Fatal(err)
+	}
+
+	stdin, stdinPipe := io.Pipe()
+	stdout, stdoutPipe := io.Pipe()
+
+	// Try to avoid the timeout in destroy. Best effort, don't check error
+	defer func() {
+		closeWrap(stdin, stdinPipe, stdout, stdoutPipe)
+		container.Kill()
+	}()
+
+	// Attach to it
+	c1 := make(chan struct{})
+	go func() {
+		defer close(c1)
+
+		r := &hijackTester{
+			ResponseRecorder: httptest.NewRecorder(),
+			in:               stdin,
+			out:              stdoutPipe,
+		}
+
+		req, err := http.NewRequest("POST", "/containers/"+container.ID+"/attach?stream=1&stdin=1&stdout=1&stderr=1", bytes.NewReader([]byte{}))
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		if err := postContainersAttach(srv, APIVERSION, r, req, map[string]string{"name": container.ID}); err != nil {
+			t.Fatal(err)
+		}
+	}()
+
+	// Acknowledge hijack
+	setTimeout(t, "hijack acknowledge timed out", 2*time.Second, func() {
+		stdout.Read([]byte{})
+		stdout.Read(make([]byte, 4096))
+	})
+
+	setTimeout(t, "read/write assertion timed out", 2*time.Second, func() {
+		if err := assertPipe("hello\n", string([]byte{2, 0, 0, 0, 0, 0, 0, 6})+"hello", stdout, stdinPipe, 15); err != nil {
 			t.Fatal(err)
 		}
 	})

commands.go

@@ -1230,7 +1230,7 @@ func (cli *DockerCli) CmdLogs(args ...string) error {
 		return nil
 	}
 
-	if err := cli.hijack("POST", "/containers/"+cmd.Arg(0)+"/attach?logs=1&stdout=1&stderr=1", false, nil, cli.out); err != nil {
+	if err := cli.hijack("POST", "/containers/"+cmd.Arg(0)+"/attach?logs=1&stdout=1&stderr=1", false, nil, cli.out, cli.err); err != nil {
 		return err
 	}
 	return nil
@@ -1273,7 +1273,7 @@ func (cli *DockerCli) CmdAttach(args ...string) error {
 	v.Set("stdout", "1")
 	v.Set("stderr", "1")
 
-	if err := cli.hijack("POST", "/containers/"+cmd.Arg(0)+"/attach?"+v.Encode(), container.Config.Tty, cli.in, cli.out); err != nil {
+	if err := cli.hijack("POST", "/containers/"+cmd.Arg(0)+"/attach?"+v.Encode(), container.Config.Tty, cli.in, cli.out, cli.err); err != nil {
 		return err
 	}
 	return nil
@@ -1537,7 +1537,7 @@ func (cli *DockerCli) CmdRun(args ...string) error {
 		v := url.Values{}
 		v.Set("logs", "1")
 		v.Set("stream", "1")
-		var out io.Writer
+		var out, stderr io.Writer
 
 		if config.AttachStdin {
 			v.Set("stdin", "1")
@@ -1548,7 +1548,11 @@ func (cli *DockerCli) CmdRun(args ...string) error {
 		}
 		if config.AttachStderr {
 			v.Set("stderr", "1")
-			out = cli.out
+			if config.Tty {
+				stderr = cli.out
+			} else {
+				stderr = cli.err
+			}
 		}
 
 		signals := make(chan os.Signal, 1)
@@ -1562,7 +1566,7 @@ func (cli *DockerCli) CmdRun(args ...string) error {
 			}
 		}()
 
-		if err := cli.hijack("POST", "/containers/"+runResult.ID+"/attach?"+v.Encode(), config.Tty, cli.in, out); err != nil {
+		if err := cli.hijack("POST", "/containers/"+runResult.ID+"/attach?"+v.Encode(), config.Tty, cli.in, out, stderr); err != nil {
 			utils.Debugf("Error hijack: %s", err)
 			return err
 		}
@@ -1729,7 +1733,7 @@ func (cli *DockerCli) stream(method, path string, in io.Reader, out io.Writer, h
 	return nil
 }
 
-func (cli *DockerCli) hijack(method, path string, setRawTerminal bool, in io.ReadCloser, out io.Writer) error {
+func (cli *DockerCli) hijack(method, path string, setRawTerminal bool, in io.ReadCloser, stdout, stderr io.Writer) error {
 
 	req, err := http.NewRequest(method, fmt.Sprintf("/v%g%s", APIVERSION, path), nil)
 	if err != nil {
@@ -1755,10 +1759,16 @@ func (cli *DockerCli) hijack(method, path string, setRawTerminal bool, in io.Rea
 	rwc, br := clientconn.Hijack()
 	defer rwc.Close()
 
-	var receiveStdout (chan error)
-	if out != nil {
-		receiveStdout = utils.Go(func() error {
-			_, err := io.Copy(out, br)
+	var receiveStdout chan error
+
+	if stdout != nil {
+		receiveStdout = utils.Go(func() (err error) {
+			// When TTY is ON, use regular copy
+			if setRawTerminal {
+				_, err = io.Copy(stdout, br)
+			} else {
+				_, err = utils.StdCopy(stdout, stderr, br)
+			}
 			utils.Debugf("[hijack] End of stdout")
 			return err
 		})
@@ -1790,7 +1800,7 @@ func (cli *DockerCli) hijack(method, path string, setRawTerminal bool, in io.Rea
 		return nil
 	})
 
-	if out != nil {
+	if stdout != nil {
 		if err := <-receiveStdout; err != nil {
 			utils.Debugf("Error receiveStdout: %s", err)
 			return err

docs/sources/api/docker_remote_api.rst

@@ -27,14 +27,29 @@ Docker Remote API
 2. Versions
 ===========
 
-The current version of the API is 1.5
+The current version of the API is 1.6
 
 Calling /images/<name>/insert is the same as calling
-/v1.5/images/<name>/insert 
+/v1.6/images/<name>/insert
 
 You can still call an old version of the api using
 /v1.0/images/<name>/insert
 
+:doc:`docker_remote_api_v1.6`
+*****************************
+
+What's new
+----------
+
+.. http:post:: /containers/(id)/attach
+
+   **New!** You can now split stderr from stdout. This is done by prefixing
+   a header to each transmition. See :http:post:`/containers/(id)/attach`.
+   The WebSocket attach is unchanged.
+   Note that attach calls on the previous API version didn't change. Stdout and
+   stderr are merged.
+
+
 :doc:`docker_remote_api_v1.5`
 *****************************
 

docs/sources/api/docker_remote_api_v1.6.rst

@@ -0,0 +1,1218 @@
+:title: Remote API v1.6
+:description: API Documentation for Docker
+:keywords: API, Docker, rcli, REST, documentation
+
+:orphan:
+
+======================
+Docker Remote API v1.6
+======================
+
+.. contents:: Table of Contents
+
+1. Brief introduction
+=====================
+
+- The Remote API is replacing rcli
+- Default port in the docker daemon is 4243
+- The API tends to be REST, but for some complex commands, like attach or pull, the HTTP connection is hijacked to transport stdout stdin and stderr
+
+2. Endpoints
+============
+
+2.1 Containers
+--------------
+
+List containers
+***************
+
+.. http:get:: /containers/json
+
+	List containers
+
+	**Example request**:
+
+	.. sourcecode:: http
+
+	   GET /containers/json?all=1&before=8dfafdbc3a40&size=1 HTTP/1.1
+	   
+	**Example response**:
+
+	.. sourcecode:: http
+
+	   HTTP/1.1 200 OK
+	   Content-Type: application/json
+	   
+	   [
+		{
+			"Id": "8dfafdbc3a40",
+			"Image": "base:latest",
+			"Command": "echo 1",
+			"Created": 1367854155,
+			"Status": "Exit 0",
+			"Ports":[{"PrivatePort": 2222, "PublicPort": 3333, "Type": "tcp"}],
+			"SizeRw":12288,
+			"SizeRootFs":0
+		},
+		{
+			"Id": "9cd87474be90",
+			"Image": "base:latest",
+			"Command": "echo 222222",
+			"Created": 1367854155,
+			"Status": "Exit 0",
+			"Ports":[],
+			"SizeRw":12288,
+			"SizeRootFs":0
+		},
+		{
+			"Id": "3176a2479c92",
+			"Image": "base:latest",
+			"Command": "echo 3333333333333333",
+			"Created": 1367854154,
+			"Status": "Exit 0",
+			"Ports":[],
+			"SizeRw":12288,
+			"SizeRootFs":0
+		},
+		{
+			"Id": "4cb07b47f9fb",
+			"Image": "base:latest",
+			"Command": "echo 444444444444444444444444444444444",
+			"Created": 1367854152,
+			"Status": "Exit 0",
+			"Ports":[],
+			"SizeRw":12288,
+			"SizeRootFs":0
+		}
+	   ]
+ 
+	:query all: 1/True/true or 0/False/false, Show all containers. Only running containers are shown by default
+	:query limit: Show ``limit`` last created containers, include non-running ones.
+	:query since: Show only containers created since Id, include non-running ones.
+	:query before: Show only containers created before Id, include non-running ones.
+	:query size: 1/True/true or 0/False/false, Show the containers sizes
+	:statuscode 200: no error
+	:statuscode 400: bad parameter
+	:statuscode 500: server error
+
+
+Create a container
+******************
+
+.. http:post:: /containers/create
+
+	Create a container
+
+	**Example request**:
+
+	.. sourcecode:: http
+
+	   POST /containers/create HTTP/1.1
+	   Content-Type: application/json
+
+	   {
+		"Hostname":"",
+		"User":"",
+		"Memory":0,
+		"MemorySwap":0,
+		"AttachStdin":false,
+		"AttachStdout":true,
+		"AttachStderr":true,
+		"PortSpecs":null,
+		"Privileged": false,
+		"Tty":false,
+		"OpenStdin":false,
+		"StdinOnce":false,
+		"Env":null,
+		"Cmd":[
+			"date"
+		],
+		"Dns":null,
+		"Image":"base",
+		"Volumes":{},
+		"VolumesFrom":"",
+		"WorkingDir":""
+
+	   }
+	   
+	**Example response**:
+
+	.. sourcecode:: http
+
+	   HTTP/1.1 201 OK
+	   Content-Type: application/json
+
+	   {
+		"Id":"e90e34656806"
+		"Warnings":[]
+	   }
+	
+	:jsonparam config: the container's configuration
+	:statuscode 201: no error
+	:statuscode 404: no such container
+	:statuscode 406: impossible to attach (container not running)
+	:statuscode 500: server error
+
+
+Inspect a container
+*******************
+
+.. http:get:: /containers/(id)/json
+
+	Return low-level information on the container ``id``
+
+	**Example request**:
+
+	.. sourcecode:: http
+
+	   GET /containers/4fa6e0f0c678/json HTTP/1.1
+	   
+	**Example response**:
+
+	.. sourcecode:: http
+
+	   HTTP/1.1 200 OK
+	   Content-Type: application/json
+
+	   {
+			"Id": "4fa6e0f0c6786287e131c3852c58a2e01cc697a68231826813597e4994f1d6e2",
+			"Created": "2013-05-07T14:51:42.041847+02:00",
+			"Path": "date",
+			"Args": [],
+			"Config": {
+				"Hostname": "4fa6e0f0c678",
+				"User": "",
+				"Memory": 0,
+				"MemorySwap": 0,
+				"AttachStdin": false,
+				"AttachStdout": true,
+				"AttachStderr": true,
+				"PortSpecs": null,
+				"Tty": false,
+				"OpenStdin": false,
+				"StdinOnce": false,
+				"Env": null,
+				"Cmd": [
+					"date"
+				],
+				"Dns": null,
+				"Image": "base",
+				"Volumes": {},
+				"VolumesFrom": "",
+				"WorkingDir":""
+
+			},
+			"State": {
+				"Running": false,
+				"Pid": 0,
+				"ExitCode": 0,
+				"StartedAt": "2013-05-07T14:51:42.087658+02:01360",
+				"Ghost": false
+			},
+			"Image": "b750fe79269d2ec9a3c593ef05b4332b1d1a02a62b4accb2c21d589ff2f5f2dc",
+			"NetworkSettings": {
+				"IpAddress": "",
+				"IpPrefixLen": 0,
+				"Gateway": "",
+				"Bridge": "",
+				"PortMapping": null
+			},
+			"SysInitPath": "/home/kitty/go/src/github.com/dotcloud/docker/bin/docker",
+			"ResolvConfPath": "/etc/resolv.conf",
+			"Volumes": {}
+	   }
+
+	:statuscode 200: no error
+	:statuscode 404: no such container
+	:statuscode 500: server error
+
+
+List processes running inside a container
+*****************************************
+
+.. http:get:: /containers/(id)/top
+
+	List processes running inside the container ``id``
+
+	**Example request**:
+
+	.. sourcecode:: http
+
+	   GET /containers/4fa6e0f0c678/top HTTP/1.1
+
+	**Example response**:
+
+	.. sourcecode:: http
+
+	   HTTP/1.1 200 OK
+	   Content-Type: application/json
+
+	   {
+		"Titles":[
+			"USER",
+			"PID",
+			"%CPU",
+			"%MEM",
+			"VSZ",
+			"RSS",
+			"TTY",
+			"STAT",
+			"START",
+			"TIME",
+			"COMMAND"
+			],
+		"Processes":[
+			["root","20147","0.0","0.1","18060","1864","pts/4","S","10:06","0:00","bash"],
+			["root","20271","0.0","0.0","4312","352","pts/4","S+","10:07","0:00","sleep","10"]
+		]
+	   }
+
+	:query ps_args: ps arguments to use (eg. aux)
+	:statuscode 200: no error
+	:statuscode 404: no such container
+	:statuscode 500: server error
+
+
+Inspect changes on a container's filesystem
+*******************************************
+
+.. http:get:: /containers/(id)/changes
+
+	Inspect changes on container ``id`` 's filesystem
+
+	**Example request**:
+
+	.. sourcecode:: http
+
+	   GET /containers/4fa6e0f0c678/changes HTTP/1.1
+
+	   
+	**Example response**:
+
+	.. sourcecode:: http
+
+	   HTTP/1.1 200 OK
+	   Content-Type: application/json
+	   
+	   [
+		{
+			"Path":"/dev",
+			"Kind":0
+		},
+		{
+			"Path":"/dev/kmsg",
+			"Kind":1
+		},
+		{
+			"Path":"/test",
+			"Kind":1
+		}
+	   ]
+
+	:statuscode 200: no error
+	:statuscode 404: no such container
+	:statuscode 500: server error
+
+
+Export a container
+******************
+
+.. http:get:: /containers/(id)/export
+
+	Export the contents of container ``id``
+
+	**Example request**:
+
+	.. sourcecode:: http
+
+	   GET /containers/4fa6e0f0c678/export HTTP/1.1
+
+	   
+	**Example response**:
+
+	.. sourcecode:: http
+
+	   HTTP/1.1 200 OK
+	   Content-Type: application/octet-stream
+	   
+	   {{ STREAM }}
+
+	:statuscode 200: no error
+	:statuscode 404: no such container
+	:statuscode 500: server error
+
+
+Start a container
+*****************
+
+.. http:post:: /containers/(id)/start
+
+        Start the container ``id``
+
+        **Example request**:
+
+        .. sourcecode:: http
+
+           POST /containers/(id)/start HTTP/1.1
+           Content-Type: application/json
+
+           {
+                "Binds":["/tmp:/tmp"],
+                "LxcConf":{"lxc.utsname":"docker"}
+           }
+
+        **Example response**:
+
+        .. sourcecode:: http
+
+           HTTP/1.1 204 No Content
+           Content-Type: text/plain
+
+        :jsonparam hostConfig: the container's host configuration (optional)
+        :statuscode 204: no error
+        :statuscode 404: no such container
+        :statuscode 500: server error
+
+
+Stop a container
+****************
+
+.. http:post:: /containers/(id)/stop
+
+	Stop the container ``id``
+
+	**Example request**:
+
+	.. sourcecode:: http
+
+	   POST /containers/e90e34656806/stop?t=5 HTTP/1.1
+	   
+	**Example response**:
+
+	.. sourcecode:: http
+
+	   HTTP/1.1 204 OK
+	   	
+	:query t: number of seconds to wait before killing the container
+	:statuscode 204: no error
+	:statuscode 404: no such container
+	:statuscode 500: server error
+
+
+Restart a container
+*******************
+
+.. http:post:: /containers/(id)/restart
+
+	Restart the container ``id``
+
+	**Example request**:
+
+	.. sourcecode:: http
+
+	   POST /containers/e90e34656806/restart?t=5 HTTP/1.1
+	   
+	**Example response**:
+
+	.. sourcecode:: http
+
+	   HTTP/1.1 204 OK
+	   	
+	:query t: number of seconds to wait before killing the container
+	:statuscode 204: no error
+	:statuscode 404: no such container
+	:statuscode 500: server error
+
+
+Kill a container
+****************
+
+.. http:post:: /containers/(id)/kill
+
+	Kill the container ``id``
+
+	**Example request**:
+
+	.. sourcecode:: http
+
+	   POST /containers/e90e34656806/kill HTTP/1.1
+	   
+	**Example response**:
+
+	.. sourcecode:: http
+
+	   HTTP/1.1 204 OK
+	   	
+	:statuscode 204: no error
+	:statuscode 404: no such container
+	:statuscode 500: server error
+
+
+Attach to a container
+*********************
+
+.. http:post:: /containers/(id)/attach
+
+	Attach to the container ``id``
+
+	**Example request**:
+
+	.. sourcecode:: http
+
+	   POST /containers/16253994b7c4/attach?logs=1&stream=0&stdout=1 HTTP/1.1
+	   
+	**Example response**:
+
+	.. sourcecode:: http
+
+	   HTTP/1.1 200 OK
+	   Content-Type: application/vnd.docker.raw-stream
+
+	   {{ STREAM }}
+	   	
+	:query logs: 1/True/true or 0/False/false, return logs. Default false
+	:query stream: 1/True/true or 0/False/false, return stream. Default false
+	:query stdin: 1/True/true or 0/False/false, if stream=true, attach to stdin. Default false
+	:query stdout: 1/True/true or 0/False/false, if logs=true, return stdout log, if stream=true, attach to stdout. Default false
+	:query stderr: 1/True/true or 0/False/false, if logs=true, return stderr log, if stream=true, attach to stderr. Default false
+	:statuscode 200: no error
+	:statuscode 400: bad parameter
+	:statuscode 404: no such container
+	:statuscode 500: server error
+
+	**Stream details**:
+
+	When using the TTY setting is enabled in
+	:http:post:`/containers/create`, the stream is the raw data
+	from the process PTY and client's stdin.  When the TTY is
+	disabled, then the stream is multiplexed to separate stdout
+	and stderr.
+
+	The format is a **Header** and a **Payload** (frame).
+
+	**HEADER**
+
+	The header will contain the information on which stream write
+	the stream (stdout or stderr). It also contain the size of
+	the associated frame encoded on the last 4 bytes (uint32).
+
+	It is encoded on the first 8 bytes like this::
+
+	    header := [8]byte{STREAM_TYPE, 0, 0, 0, SIZE1, SIZE2, SIZE3, SIZE4}
+
+	``STREAM_TYPE`` can be:
+
+	- 0: stdin (will be writen on stdout)
+	- 1: stdout
+	- 2: stderr
+
+	``SIZE1, SIZE2, SIZE3, SIZE4`` are the 4 bytes of the uint32 size encoded as big endian.
+
+	**PAYLOAD**
+
+	The payload is the raw stream.
+
+	**IMPLEMENTATION**
+
+	The simplest way to implement the Attach protocol is the following:
+
+	1) Read 8 bytes
+	2) chose stdout or stderr depending on the first byte
+	3) Extract the frame size from the last 4 byets
+	4) Read the extracted size and output it on the correct output
+	5) Goto 1)
+
+
+
+Wait a container
+****************
+
+.. http:post:: /containers/(id)/wait
+
+	Block until container ``id`` stops, then returns the exit code
+
+	**Example request**:
+
+	.. sourcecode:: http
+
+	   POST /containers/16253994b7c4/wait HTTP/1.1
+	   
+	**Example response**:
+
+	.. sourcecode:: http
+
+	   HTTP/1.1 200 OK
+	   Content-Type: application/json
+
+	   {"StatusCode":0}
+	   	
+	:statuscode 200: no error
+	:statuscode 404: no such container
+	:statuscode 500: server error
+
+
+Remove a container
+*******************
+
+.. http:delete:: /containers/(id)
+
+	Remove the container ``id`` from the filesystem
+
+	**Example request**:
+
+        .. sourcecode:: http
+
+           DELETE /containers/16253994b7c4?v=1 HTTP/1.1
+
+        **Example response**:
+
+        .. sourcecode:: http
+
+	   HTTP/1.1 204 OK
+
+	:query v: 1/True/true or 0/False/false, Remove the volumes associated to the container. Default false
+        :statuscode 204: no error
+	:statuscode 400: bad parameter
+        :statuscode 404: no such container
+        :statuscode 500: server error
+
+
+Copy files or folders from a container
+**************************************
+
+.. http:post:: /containers/(id)/copy
+
+	Copy files or folders of container ``id``
+
+	**Example request**:
+
+	.. sourcecode:: http
+
+	   POST /containers/4fa6e0f0c678/copy HTTP/1.1
+	   Content-Type: application/json
+
+	   {
+		"Resource":"test.txt"
+	   }
+
+	**Example response**:
+
+	.. sourcecode:: http
+
+	   HTTP/1.1 200 OK
+	   Content-Type: application/octet-stream
+	   
+	   {{ STREAM }}
+
+	:statuscode 200: no error
+	:statuscode 404: no such container
+	:statuscode 500: server error
+
+
+2.2 Images
+----------
+
+List Images
+***********
+
+.. http:get:: /images/(format)
+
+	List images ``format`` could be json or viz (json default)
+
+	**Example request**:
+
+	.. sourcecode:: http
+
+	   GET /images/json?all=0 HTTP/1.1
+
+	**Example response**:
+
+	.. sourcecode:: http
+
+	   HTTP/1.1 200 OK
+	   Content-Type: application/json
+	   
+	   [
+		{
+			"Repository":"base",
+			"Tag":"ubuntu-12.10",
+			"Id":"b750fe79269d",
+			"Created":1364102658,
+			"Size":24653,
+			"VirtualSize":180116135
+		},
+		{
+			"Repository":"base",
+			"Tag":"ubuntu-quantal",
+			"Id":"b750fe79269d",
+			"Created":1364102658,
+			"Size":24653,
+			"VirtualSize":180116135
+		}
+	   ]
+
+
+	**Example request**:
+
+	.. sourcecode:: http
+
+	   GET /images/viz HTTP/1.1
+
+	**Example response**:
+
+	.. sourcecode:: http
+
+	   HTTP/1.1 200 OK
+	   Content-Type: text/plain
+
+	   digraph docker {
+	   "d82cbacda43a" -> "074be284591f"
+	   "1496068ca813" -> "08306dc45919"
+	   "08306dc45919" -> "0e7893146ac2"
+	   "b750fe79269d" -> "1496068ca813"
+	   base -> "27cf78414709" [style=invis]
+	   "f71189fff3de" -> "9a33b36209ed"
+	   "27cf78414709" -> "b750fe79269d"
+	   "0e7893146ac2" -> "d6434d954665"
+	   "d6434d954665" -> "d82cbacda43a"
+	   base -> "e9aa60c60128" [style=invis]
+	   "074be284591f" -> "f71189fff3de"
+	   "b750fe79269d" [label="b750fe79269d\nbase",shape=box,fillcolor="paleturquoise",style="filled,rounded"];
+	   "e9aa60c60128" [label="e9aa60c60128\nbase2",shape=box,fillcolor="paleturquoise",style="filled,rounded"];
+	   "9a33b36209ed" [label="9a33b36209ed\ntest",shape=box,fillcolor="paleturquoise",style="filled,rounded"];
+	   base [style=invisible]
+	   }
+ 
+	:query all: 1/True/true or 0/False/false, Show all containers. Only running containers are shown by default
+	:statuscode 200: no error
+	:statuscode 400: bad parameter
+	:statuscode 500: server error
+
+
+Create an image
+***************
+
+.. http:post:: /images/create
+
+	Create an image, either by pull it from the registry or by importing it
+
+	**Example request**:
+
+        .. sourcecode:: http
+
+           POST /images/create?fromImage=base HTTP/1.1
+
+        **Example response**:
+
+        .. sourcecode:: http
+
+           HTTP/1.1 200 OK
+	   Content-Type: application/json
+
+	   {"status":"Pulling..."}
+	   {"status":"Pulling", "progress":"1/? (n/a)"}
+	   {"error":"Invalid..."}
+	   ...
+
+	When using this endpoint to pull an image from the registry,
+	the ``X-Registry-Auth`` header can be used to include a
+	base64-encoded AuthConfig object.
+
+        :query fromImage: name of the image to pull
+	:query fromSrc: source to import, - means stdin
+        :query repo: repository
+	:query tag: tag
+	:query registry: the registry to pull from
+        :statuscode 200: no error
+        :statuscode 500: server error
+
+
+Insert a file in an image
+*************************
+
+.. http:post:: /images/(name)/insert
+
+	Insert a file from ``url`` in the image ``name`` at ``path``
+
+	**Example request**:
+
+        .. sourcecode:: http
+
+           POST /images/test/insert?path=/usr&url=myurl HTTP/1.1
+
+	**Example response**:
+
+        .. sourcecode:: http
+
+           HTTP/1.1 200 OK
+	   Content-Type: application/json
+
+	   {"status":"Inserting..."}
+	   {"status":"Inserting", "progress":"1/? (n/a)"}
+	   {"error":"Invalid..."}
+	   ...
+
+	:statuscode 200: no error
+        :statuscode 500: server error
+
+
+Inspect an image
+****************
+
+.. http:get:: /images/(name)/json
+
+	Return low-level information on the image ``name``
+
+	**Example request**:
+
+	.. sourcecode:: http
+
+	   GET /images/base/json HTTP/1.1
+
+	**Example response**:
+
+        .. sourcecode:: http
+
+           HTTP/1.1 200 OK
+	   Content-Type: application/json
+
+	   {
+		"id":"b750fe79269d2ec9a3c593ef05b4332b1d1a02a62b4accb2c21d589ff2f5f2dc",
+		"parent":"27cf784147099545",
+		"created":"2013-03-23T22:24:18.818426-07:00",
+		"container":"3d67245a8d72ecf13f33dffac9f79dcdf70f75acb84d308770391510e0c23ad0",
+		"container_config":
+			{
+				"Hostname":"",
+				"User":"",
+				"Memory":0,
+				"MemorySwap":0,
+				"AttachStdin":false,
+				"AttachStdout":false,
+				"AttachStderr":false,
+				"PortSpecs":null,
+				"Tty":true,
+				"OpenStdin":true,
+				"StdinOnce":false,
+				"Env":null,
+				"Cmd": ["/bin/bash"]
+				,"Dns":null,
+				"Image":"base",
+				"Volumes":null,
+				"VolumesFrom":"",
+				"WorkingDir":""
+			},
+		"Size": 6824592
+	   }
+
+	:statuscode 200: no error
+	:statuscode 404: no such image
+        :statuscode 500: server error
+
+
+Get the history of an image
+***************************
+
+.. http:get:: /images/(name)/history
+
+        Return the history of the image ``name``
+
+        **Example request**:
+
+        .. sourcecode:: http
+
+           GET /images/base/history HTTP/1.1
+
+        **Example response**:
+
+        .. sourcecode:: http
+
+           HTTP/1.1 200 OK
+	   Content-Type: application/json
+
+	   [
+		{
+			"Id":"b750fe79269d",
+			"Created":1364102658,
+			"CreatedBy":"/bin/bash"
+		},
+		{
+			"Id":"27cf78414709",
+			"Created":1364068391,
+			"CreatedBy":""
+		}
+	   ]
+
+        :statuscode 200: no error
+        :statuscode 404: no such image
+        :statuscode 500: server error
+
+
+Push an image on the registry
+*****************************
+
+.. http:post:: /images/(name)/push
+
+   Push the image ``name`` on the registry
+
+   **Example request**:
+
+   .. sourcecode:: http
+
+      POST /images/test/push HTTP/1.1
+
+   **Example response**:
+
+   .. sourcecode:: http
+
+    HTTP/1.1 200 OK
+    Content-Type: application/json
+
+   {"status":"Pushing..."}
+   {"status":"Pushing", "progress":"1/? (n/a)"}
+   {"error":"Invalid..."}
+   ...
+
+	The ``X-Registry-Auth`` header can be used to include a
+	base64-encoded AuthConfig object.
+
+   :query registry: the registry you wan to push, optional
+   :statuscode 200: no error
+        :statuscode 404: no such image
+        :statuscode 500: server error
+
+
+Tag an image into a repository
+******************************
+
+.. http:post:: /images/(name)/tag
+
+	Tag the image ``name`` into a repository
+
+        **Example request**:
+
+        .. sourcecode:: http
+			
+	   POST /images/test/tag?repo=myrepo&force=0 HTTP/1.1
+
+	**Example response**:
+
+        .. sourcecode:: http
+
+           HTTP/1.1 200 OK
+
+	:query repo: The repository to tag in
+	:query force: 1/True/true or 0/False/false, default false
+	:statuscode 200: no error
+	:statuscode 400: bad parameter
+	:statuscode 404: no such image
+	:statuscode 409: conflict
+        :statuscode 500: server error
+
+
+Remove an image
+***************
+
+.. http:delete:: /images/(name)
+
+	Remove the image ``name`` from the filesystem 
+	
+	**Example request**:
+
+	.. sourcecode:: http
+
+	   DELETE /images/test HTTP/1.1
+
+	**Example response**:
+
+        .. sourcecode:: http
+
+	   HTTP/1.1 200 OK
+	   Content-type: application/json
+
+	   [
+	    {"Untagged":"3e2f21a89f"},
+	    {"Deleted":"3e2f21a89f"},
+	    {"Deleted":"53b4f83ac9"}
+	   ]
+
+	:statuscode 200: no error
+        :statuscode 404: no such image
+	:statuscode 409: conflict
+        :statuscode 500: server error
+
+
+Search images
+*************
+
+.. http:get:: /images/search
+
+	Search for an image in the docker index
+	
+	**Example request**:
+
+        .. sourcecode:: http
+
+           GET /images/search?term=sshd HTTP/1.1
+
+	**Example response**:
+
+	.. sourcecode:: http
+
+	   HTTP/1.1 200 OK
+	   Content-Type: application/json
+	   
+	   [
+		{
+			"Name":"cespare/sshd",
+			"Description":""
+		},
+		{
+			"Name":"johnfuller/sshd",
+			"Description":""
+		},
+		{
+			"Name":"dhrp/mongodb-sshd",
+			"Description":""
+		}
+	   ]
+
+	   :query term: term to search
+	   :statuscode 200: no error
+	   :statuscode 500: server error
+
+
+2.3 Misc
+--------
+
+Build an image from Dockerfile via stdin
+****************************************
+
+.. http:post:: /build
+
+   Build an image from Dockerfile via stdin
+
+   **Example request**:
+
+   .. sourcecode:: http
+
+      POST /build HTTP/1.1
+
+      {{ STREAM }}
+
+   **Example response**:
+
+   .. sourcecode:: http
+
+      HTTP/1.1 200 OK
+
+      {{ STREAM }}
+
+
+       The stream must be a tar archive compressed with one of the following algorithms:
+       identity (no compression), gzip, bzip2, xz. The archive must include a file called
+       `Dockerfile` at its root. It may include any number of other files, which will be
+       accessible in the build context (See the ADD build command).
+
+       The Content-type header should be set to "application/tar".
+
+	:query t: repository name (and optionally a tag) to be applied to the resulting image in case of success
+	:query q: suppress verbose build output
+    :query nocache: do not use the cache when building the image
+	:statuscode 200: no error
+    :statuscode 500: server error
+
+
+Check auth configuration
+************************
+
+.. http:post:: /auth
+
+        Get the default username and email
+
+        **Example request**:
+
+        .. sourcecode:: http
+
+           POST /auth HTTP/1.1
+	   Content-Type: application/json
+
+	   {
+		"username":"hannibal",
+		"password:"xxxx",
+		"email":"hannibal@a-team.com",
+		"serveraddress":"https://index.docker.io/v1/"
+	   }
+
+        **Example response**:
+
+        .. sourcecode:: http
+
+           HTTP/1.1 200 OK
+
+        :statuscode 200: no error
+        :statuscode 204: no error
+        :statuscode 500: server error
+
+
+Display system-wide information
+*******************************
+
+.. http:get:: /info
+
+	Display system-wide information
+	
+	**Example request**:
+
+        .. sourcecode:: http
+
+           GET /info HTTP/1.1
+
+        **Example response**:
+
+        .. sourcecode:: http
+
+           HTTP/1.1 200 OK
+	   Content-Type: application/json
+
+	   {
+		"Containers":11,
+		"Images":16,
+		"Debug":false,
+		"NFd": 11,
+		"NGoroutines":21,
+		"MemoryLimit":true,
+		"SwapLimit":false,
+		"IPv4Forwarding":true
+	   }
+
+        :statuscode 200: no error
+        :statuscode 500: server error
+
+
+Show the docker version information
+***********************************
+
+.. http:get:: /version
+
+	Show the docker version information
+
+	**Example request**:
+
+        .. sourcecode:: http
+
+           GET /version HTTP/1.1
+
+        **Example response**:
+
+        .. sourcecode:: http
+
+           HTTP/1.1 200 OK
+	   Content-Type: application/json
+
+	   {
+		"Version":"0.2.2",
+		"GitCommit":"5a2a5cc+CHANGES",
+		"GoVersion":"go1.0.3"
+	   }
+
+        :statuscode 200: no error
+	:statuscode 500: server error
+
+
+Create a new image from a container's changes
+*********************************************
+
+.. http:post:: /commit
+
+    Create a new image from a container's changes
+
+    **Example request**:
+
+    .. sourcecode:: http
+
+        POST /commit?container=44c004db4b17&m=message&repo=myrepo HTTP/1.1
+
+    **Example response**:
+
+    .. sourcecode:: http
+
+        HTTP/1.1 201 OK
+	    Content-Type: application/vnd.docker.raw-stream
+
+        {"Id":"596069db4bf5"}
+
+    :query container: source container
+    :query repo: repository
+    :query tag: tag
+    :query m: commit message
+    :query author: author (eg. "John Hannibal Smith <hannibal@a-team.com>")
+    :query run: config automatically applied when the image is run. (ex: {"Cmd": ["cat", "/world"], "PortSpecs":["22"]})
+    :statuscode 201: no error
+    :statuscode 404: no such container
+    :statuscode 500: server error
+
+
+Monitor Docker's events
+***********************
+
+.. http:get:: /events
+
+	Get events from docker, either in real time via streaming, or via polling (using `since`)
+
+	**Example request**:
+
+	.. sourcecode:: http
+
+           POST /events?since=1374067924
+
+        **Example response**:
+
+        .. sourcecode:: http
+
+           HTTP/1.1 200 OK
+	   Content-Type: application/json
+
+	   {"status":"create","id":"dfdf82bd3881","from":"base:latest","time":1374067924}
+	   {"status":"start","id":"dfdf82bd3881","from":"base:latest","time":1374067924}
+	   {"status":"stop","id":"dfdf82bd3881","from":"base:latest","time":1374067966}
+	   {"status":"destroy","id":"dfdf82bd3881","from":"base:latest","time":1374067970}
+
+	:query since: timestamp used for polling
+        :statuscode 200: no error
+        :statuscode 500: server error
+
+
+3. Going further
+================
+
+3.1 Inside 'docker run'
+-----------------------
+
+Here are the steps of 'docker run' :
+
+* Create the container
+* If the status code is 404, it means the image doesn't exists:
+        * Try to pull it
+        * Then retry to create the container
+* Start the container
+* If you are not in detached mode:
+        * Attach to the container, using logs=1 (to have stdout and stderr from the container's start) and stream=1
+* If in detached mode or only stdin is attached:
+	* Display the container's id
+
+
+3.2 Hijacking
+-------------
+
+In this version of the API, /attach, uses hijacking to transport stdin, stdout and stderr on the same socket. This might change in the future.
+
+3.3 CORS Requests
+-----------------
+
+To enable cross origin requests to the remote api add the flag "-api-enable-cors" when running docker in daemon mode.
+
+.. code-block:: bash
+
+   docker -d -H="192.168.1.9:4243" -api-enable-cors
+

server.go

@@ -1177,11 +1177,12 @@ func (srv *Server) ContainerResize(name string, h, w int) error {
 	return fmt.Errorf("No such container: %s", name)
 }
 
-func (srv *Server) ContainerAttach(name string, logs, stream, stdin, stdout, stderr bool, in io.ReadCloser, out io.Writer) error {
+func (srv *Server) ContainerAttach(name string, logs, stream, stdin, stdout, stderr bool, inStream io.ReadCloser, outStream, errStream io.Writer) error {
 	container := srv.runtime.Get(name)
 	if container == nil {
 		return fmt.Errorf("No such container: %s", name)
 	}
+
 	//logs
 	if logs {
 		cLog, err := container.ReadLog("json")
@@ -1192,7 +1193,7 @@ func (srv *Server) ContainerAttach(name string, logs, stream, stdin, stdout, std
 				cLog, err := container.ReadLog("stdout")
 				if err != nil {
 					utils.Debugf("Error reading logs (stdout): %s", err)
-				} else if _, err := io.Copy(out, cLog); err != nil {
+				} else if _, err := io.Copy(outStream, cLog); err != nil {
 					utils.Debugf("Error streaming logs (stdout): %s", err)
 				}
 			}
@@ -1200,7 +1201,7 @@ func (srv *Server) ContainerAttach(name string, logs, stream, stdin, stdout, std
 				cLog, err := container.ReadLog("stderr")
 				if err != nil {
 					utils.Debugf("Error reading logs (stderr): %s", err)
-				} else if _, err := io.Copy(out, cLog); err != nil {
+				} else if _, err := io.Copy(errStream, cLog); err != nil {
 					utils.Debugf("Error streaming logs (stderr): %s", err)
 				}
 			}
@@ -1209,15 +1210,19 @@ func (srv *Server) ContainerAttach(name string, logs, stream, stdin, stdout, std
 		} else {
 			dec := json.NewDecoder(cLog)
 			for {
-				var l utils.JSONLog
-				if err := dec.Decode(&l); err == io.EOF {
+				l := &utils.JSONLog{}
+
+				if err := dec.Decode(l); err == io.EOF {
 					break
 				} else if err != nil {
 					utils.Debugf("Error streaming logs: %s", err)
 					break
 				}
-				if (l.Stream == "stdout" && stdout) || (l.Stream == "stderr" && stderr) {
-					fmt.Fprintf(out, "%s", l.Log)
+				if l.Stream == "stdout" && stdout {
+					fmt.Fprintf(outStream, "%s", l.Log)
+				}
+				if l.Stream == "stderr" && stderr {
+					fmt.Fprintf(errStream, "%s", l.Log)
 				}
 			}
 		}
@@ -1240,16 +1245,16 @@ func (srv *Server) ContainerAttach(name string, logs, stream, stdin, stdout, std
 			go func() {
 				defer w.Close()
 				defer utils.Debugf("Closing buffered stdin pipe")
-				io.Copy(w, in)
+				io.Copy(w, inStream)
 			}()
 			cStdin = r
-			cStdinCloser = in
+			cStdinCloser = inStream
 		}
 		if stdout {
-			cStdout = out
+			cStdout = outStream
 		}
 		if stderr {
-			cStderr = out
+			cStderr = errStream
 		}
 
 		<-container.Attach(cStdin, cStdinCloser, cStdout, cStderr)

utils/stdcopy.go

@@ -0,0 +1,152 @@
+package utils
+
+import (
+	"encoding/binary"
+	"errors"
+	"io"
+)
+
+const (
+	StdWriterPrefixLen = 8
+	StdWriterFdIndex   = 0
+	StdWriterSizeIndex = 4
+)
+
+type StdType [StdWriterPrefixLen]byte
+
+var (
+	Stdin  StdType = StdType{0: 0}
+	Stdout StdType = StdType{0: 1}
+	Stderr StdType = StdType{0: 2}
+)
+
+type StdWriter struct {
+	io.Writer
+	prefix  StdType
+	sizeBuf []byte
+}
+
+func (w *StdWriter) Write(buf []byte) (n int, err error) {
+	if w == nil || w.Writer == nil {
+		return 0, errors.New("Writer not instanciated")
+	}
+	binary.BigEndian.PutUint32(w.prefix[4:], uint32(len(buf)))
+	buf = append(w.prefix[:], buf...)
+
+	n, err = w.Writer.Write(buf)
+	return n - StdWriterPrefixLen, err
+}
+
+// NewStdWriter instanciate a new Writer based on the given type `t`.
+// the utils package contains the valid parametres for `t`:
+func NewStdWriter(w io.Writer, t StdType) *StdWriter {
+	if len(t) != StdWriterPrefixLen {
+		return nil
+	}
+
+	return &StdWriter{
+		Writer:  w,
+		prefix:  t,
+		sizeBuf: make([]byte, 4),
+	}
+}
+
+var ErrInvalidStdHeader = errors.New("Unrecognized input header")
+
+// StdCopy is a modified version of io.Copy.
+//
+// StdCopy copies from src to dstout or dsterr until either EOF is reached
+// on src or an error occurs.  It returns the number of bytes
+// copied and the first error encountered while copying, if any.
+//
+// A successful Copy returns err == nil, not err == EOF.
+// Because Copy is defined to read from src until EOF, it does
+// not treat an EOF from Read as an error to be reported.
+//
+// The source needs to be writter via StdWriter, dstout or dsterr is selected
+// based on the prefix added by StdWriter
+func StdCopy(dstout, dsterr io.Writer, src io.Reader) (written int64, err error) {
+	var (
+		buf       = make([]byte, 32*1024+StdWriterPrefixLen+1)
+		bufLen    = len(buf)
+		nr, nw    int
+		er, ew    error
+		out       io.Writer
+		frameSize int
+	)
+
+	for {
+		// Make sure we have at least a full header
+		for nr < StdWriterPrefixLen {
+			var nr2 int
+			nr2, er = src.Read(buf[nr:])
+			if er == io.EOF {
+				return written, nil
+			}
+			if er != nil {
+				return 0, er
+			}
+			nr += nr2
+		}
+
+		// Check the first byte to know where to write
+		switch buf[StdWriterFdIndex] {
+		case 0:
+			fallthrough
+		case 1:
+			// Write on stdout
+			out = dstout
+		case 2:
+			// Write on stderr
+			out = dsterr
+		default:
+			Debugf("Error selecting output fd: (%d)", buf[StdWriterFdIndex])
+			return 0, ErrInvalidStdHeader
+		}
+
+		// Retrieve the size of the frame
+		frameSize = int(binary.BigEndian.Uint32(buf[StdWriterSizeIndex : StdWriterSizeIndex+4]))
+
+		// Check if the buffer is big enough to read the frame.
+		// Extend it if necessary.
+		if frameSize+StdWriterPrefixLen > bufLen {
+			Debugf("Extending buffer cap.")
+			buf = append(buf, make([]byte, frameSize-len(buf)+1)...)
+			bufLen = len(buf)
+		}
+
+		// While the amount of bytes read is less than the size of the frame + header, we keep reading
+		for nr < frameSize+StdWriterPrefixLen {
+			var nr2 int
+			nr2, er = src.Read(buf[nr:])
+			if er == io.EOF {
+				return written, nil
+			}
+			if er != nil {
+				Debugf("Error reading frame: %s", er)
+				return 0, er
+			}
+			nr += nr2
+		}
+
+		// Write the retrieved frame (without header)
+		nw, ew = out.Write(buf[StdWriterPrefixLen : frameSize+StdWriterPrefixLen])
+		if nw > 0 {
+			written += int64(nw)
+		}
+		if ew != nil {
+			Debugf("Error writing frame: %s", ew)
+			return 0, ew
+		}
+		// If the frame has not been fully written: error
+		if nw != frameSize {
+			Debugf("Error Short Write: (%d on %d)", nw, frameSize)
+			return 0, io.ErrShortWrite
+		}
+
+		// Move the rest of the buffer to the beginning
+		copy(buf, buf[frameSize+StdWriterPrefixLen:])
+		// Move the index
+		nr -= frameSize + StdWriterPrefixLen
+	}
+}