Add ContainerCreateResponse type

This type is produced on the server side and is a type safe struct that
can be encoded to json.  It is consumed via the client.

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>

api/client/commands.go

@@ -2120,7 +2120,7 @@ func (cid *cidFile) Write(id string) error {
 	return nil
 }
 
-func (cli *DockerCli) createContainer(config *runconfig.Config, hostConfig *runconfig.HostConfig, cidfile, name string) (engine.Env, error) {
+func (cli *DockerCli) createContainer(config *runconfig.Config, hostConfig *runconfig.HostConfig, cidfile, name string) (*types.ContainerCreateResponse, error) {
 	containerValues := url.Values{}
 	if name != "" {
 		containerValues.Set("name", name)
@@ -2159,23 +2159,19 @@ func (cli *DockerCli) createContainer(config *runconfig.Config, hostConfig *runc
 		return nil, err
 	}
 
-	var result engine.Env
+	var response types.ContainerCreateResponse
-	if err := result.Decode(stream); err != nil {
+	if err := json.NewDecoder(stream).Decode(&response); err != nil {
 		return nil, err
 	}
-
+	for _, warning := range response.Warnings {
-	for _, warning := range result.GetList("Warnings") {
 		fmt.Fprintf(cli.err, "WARNING: %s\n", warning)
 	}
-
 	if containerIDFile != nil {
-		if err = containerIDFile.Write(result.Get("Id")); err != nil {
+		if err = containerIDFile.Write(response.ID); err != nil {
 			return nil, err
 		}
 	}
-
+	return &response, nil
-	return result, nil
-
 }
 
 func (cli *DockerCli) CmdCreate(args ...string) error {
@@ -2194,14 +2190,11 @@ func (cli *DockerCli) CmdCreate(args ...string) error {
 		cmd.Usage()
 		return nil
 	}
-
+	response, err := cli.createContainer(config, hostConfig, hostConfig.ContainerIDFile, *flName)
-	createResult, err := cli.createContainer(config, hostConfig, hostConfig.ContainerIDFile, *flName)
 	if err != nil {
 		return err
 	}
-
+	fmt.Fprintf(cli.out, "%s\n", response.ID)
-	fmt.Fprintf(cli.out, "%s\n", createResult.Get("Id"))
-
 	return nil
 }
 
@@ -2259,38 +2252,32 @@ func (cli *DockerCli) CmdRun(args ...string) error {
 		sigProxy = false
 	}
 
-	runResult, err := cli.createContainer(config, hostConfig, hostConfig.ContainerIDFile, *flName)
+	createResponse, err := cli.createContainer(config, hostConfig, hostConfig.ContainerIDFile, *flName)
 	if err != nil {
 		return err
 	}
-
 	if sigProxy {
-		sigc := cli.forwardAllSignals(runResult.Get("Id"))
+		sigc := cli.forwardAllSignals(createResponse.ID)
 		defer signal.StopCatch(sigc)
 	}
-
 	var (
 		waitDisplayId chan struct{}
 		errCh         chan error
 	)
-
 	if !config.AttachStdout && !config.AttachStderr {
 		// Make this asynchronous to allow the client to write to stdin before having to read the ID
 		waitDisplayId = make(chan struct{})
 		go func() {
 			defer close(waitDisplayId)
-			fmt.Fprintf(cli.out, "%s\n", runResult.Get("Id"))
+			fmt.Fprintf(cli.out, "%s\n", createResponse.ID)
 		}()
 	}
-
 	if *flAutoRemove && (hostConfig.RestartPolicy.Name == "always" || hostConfig.RestartPolicy.Name == "on-failure") {
 		return ErrConflictRestartPolicyAndAutoRemove
 	}
-
 	// We need to instantiate the chan because the select needs it. It can
 	// be closed but can't be uninitialized.
 	hijacked := make(chan io.Closer)
-
 	// Block the return until the chan gets closed
 	defer func() {
 		log.Debugf("End of CmdRun(), Waiting for hijack to finish.")
@@ -2298,7 +2285,6 @@ func (cli *DockerCli) CmdRun(args ...string) error {
 			log.Errorf("Hijack did not finish (chan still open)")
 		}
 	}()
-
 	if config.AttachStdin || config.AttachStdout || config.AttachStderr {
 		var (
 			out, stderr io.Writer
@@ -2306,7 +2292,6 @@ func (cli *DockerCli) CmdRun(args ...string) error {
 			v           = url.Values{}
 		)
 		v.Set("stream", "1")
-
 		if config.AttachStdin {
 			v.Set("stdin", "1")
 			in = cli.in
@@ -2323,14 +2308,12 @@ func (cli *DockerCli) CmdRun(args ...string) error {
 				stderr = cli.err
 			}
 		}
-
 		errCh = promise.Go(func() error {
-			return cli.hijack("POST", "/containers/"+runResult.Get("Id")+"/attach?"+v.Encode(), config.Tty, in, out, stderr, hijacked, nil)
+			return cli.hijack("POST", "/containers/"+createResponse.ID+"/attach?"+v.Encode(), config.Tty, in, out, stderr, hijacked, nil)
 		})
 	} else {
 		close(hijacked)
 	}
-
 	// Acknowledge the hijack before starting
 	select {
 	case closer := <-hijacked:
@@ -2347,12 +2330,12 @@ func (cli *DockerCli) CmdRun(args ...string) error {
 	}
 
 	//start the container
-	if _, _, err = readBody(cli.call("POST", "/containers/"+runResult.Get("Id")+"/start", nil, false)); err != nil {
+	if _, _, err = readBody(cli.call("POST", "/containers/"+createResponse.ID+"/start", nil, false)); err != nil {
 		return err
 	}
 
 	if (config.AttachStdin || config.AttachStdout || config.AttachStderr) && config.Tty && cli.isTerminalOut {
-		if err := cli.monitorTtySize(runResult.Get("Id"), false); err != nil {
+		if err := cli.monitorTtySize(createResponse.ID, false); err != nil {
 			log.Errorf("Error monitoring TTY size: %s", err)
 		}
 	}
@@ -2377,26 +2360,26 @@ func (cli *DockerCli) CmdRun(args ...string) error {
 	if *flAutoRemove {
 		// Autoremove: wait for the container to finish, retrieve
 		// the exit code and remove the container
-		if _, _, err := readBody(cli.call("POST", "/containers/"+runResult.Get("Id")+"/wait", nil, false)); err != nil {
+		if _, _, err := readBody(cli.call("POST", "/containers/"+createResponse.ID+"/wait", nil, false)); err != nil {
 			return err
 		}
-		if _, status, err = getExitCode(cli, runResult.Get("Id")); err != nil {
+		if _, status, err = getExitCode(cli, createResponse.ID); err != nil {
 			return err
 		}
-		if _, _, err := readBody(cli.call("DELETE", "/containers/"+runResult.Get("Id")+"?v=1", nil, false)); err != nil {
+		if _, _, err := readBody(cli.call("DELETE", "/containers/"+createResponse.ID+"?v=1", nil, false)); err != nil {
 			return err
 		}
 	} else {
 		// No Autoremove: Simply retrieve the exit code
 		if !config.Tty {
 			// In non-TTY mode, we can't detach, so we must wait for container exit
-			if status, err = waitForExit(cli, runResult.Get("Id")); err != nil {
+			if status, err = waitForExit(cli, createResponse.ID); err != nil {
 				return err
 			}
 		} else {
 			// In TTY mode, there is a race: if the process dies too slowly, the state could
 			// be updated after the getExitCode call and result in the wrong exit code being reported
-			if _, status, err = getExitCode(cli, runResult.Get("Id")); err != nil {
+			if _, status, err = getExitCode(cli, createResponse.ID); err != nil {
 				return err
 			}
 		}

api/server/server.go

@@ -27,6 +27,7 @@ import (
 
 	log "github.com/Sirupsen/logrus"
 	"github.com/docker/docker/api"
+	"github.com/docker/docker/api/types"
 	"github.com/docker/docker/daemon/networkdriver/portallocator"
 	"github.com/docker/docker/engine"
 	"github.com/docker/docker/pkg/listenbuffer"
@@ -140,12 +141,22 @@ func httpError(w http.ResponseWriter, err error) {
 	}
 }
 
-func writeJSON(w http.ResponseWriter, code int, v engine.Env) error {
+// writeJSONEnv writes the engine.Env values to the http response stream as a
+// json encoded body.
+func writeJSONEnv(w http.ResponseWriter, code int, v engine.Env) error {
 	w.Header().Set("Content-Type", "application/json")
 	w.WriteHeader(code)
 	return v.Encode(w)
 }
 
+// writeJSON writes the value v to the http response stream as json with standard
+// json encoding.
+func writeJSON(w http.ResponseWriter, code int, v interface{}) error {
+	w.Header().Set("Content-Type", "application/json")
+	w.WriteHeader(code)
+	return json.NewEncoder(w).Encode(v)
+}
+
 func streamJSON(job *engine.Job, w http.ResponseWriter, flush bool) {
 	w.Header().Set("Content-Type", "application/json")
 	if flush {
@@ -183,7 +194,7 @@ func postAuth(eng *engine.Engine, version version.Version, w http.ResponseWriter
 	if status := engine.Tail(stdoutBuffer, 1); status != "" {
 		var env engine.Env
 		env.Set("Status", status)
-		return writeJSON(w, http.StatusOK, env)
+		return writeJSONEnv(w, http.StatusOK, env)
 	}
 	w.WriteHeader(http.StatusNoContent)
 	return nil
@@ -525,7 +536,7 @@ func postCommit(eng *engine.Engine, version version.Version, w http.ResponseWrit
 		return err
 	}
 	env.Set("Id", engine.Tail(stdoutBuffer, 1))
-	return writeJSON(w, http.StatusCreated, env)
+	return writeJSONEnv(w, http.StatusCreated, env)
 }
 
 // Creates an image from Pull or from Import
@@ -703,18 +714,16 @@ func postContainersCreate(eng *engine.Engine, version version.Version, w http.Re
 	if err := parseForm(r); err != nil {
 		return nil
 	}
+	if err := checkForJson(r); err != nil {
+		return err
+	}
 	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
 	}
@@ -730,10 +739,10 @@ func postContainersCreate(eng *engine.Engine, version version.Version, w http.Re
 	for scanner.Scan() {
 		outWarnings = append(outWarnings, scanner.Text())
 	}
-	out.Set("Id", engine.Tail(stdoutBuffer, 1))
+	return writeJSON(w, http.StatusCreated, &types.ContainerCreateResponse{
-	out.SetList("Warnings", outWarnings)
+		ID:       engine.Tail(stdoutBuffer, 1),
-
+		Warnings: outWarnings,
-	return writeJSON(w, http.StatusCreated, out)
+	})
 }
 
 func postContainersRestart(eng *engine.Engine, version version.Version, w http.ResponseWriter, r *http.Request, vars map[string]string) error {
@@ -876,7 +885,7 @@ func postContainersWait(eng *engine.Engine, version version.Version, w http.Resp
 	}
 
 	env.Set("StatusCode", engine.Tail(stdoutBuffer, 1))
-	return writeJSON(w, http.StatusOK, env)
+	return writeJSONEnv(w, http.StatusOK, env)
 }
 
 func postContainersResize(eng *engine.Engine, version version.Version, w http.ResponseWriter, r *http.Request, vars map[string]string) error {
@@ -1147,7 +1156,7 @@ func postContainerExecCreate(eng *engine.Engine, version version.Version, w http
 	// Return the ID
 	out.Set("Id", engine.Tail(stdoutBuffer, 1))
 
-	return writeJSON(w, http.StatusCreated, out)
+	return writeJSONEnv(w, http.StatusCreated, out)
 }
 
 // TODO(vishh): Refactor the code to avoid having to specify stream config as part of both create and start.

api/types/types.go

@@ -0,0 +1,11 @@
+package types
+
+// ContainerCreateResponse contains the information returned to a client on the
+// creation of a new container.
+type ContainerCreateResponse struct {
+	// ID is the ID of the created container.
+	ID string `json:"Id"`
+
+	// Warnings are any warnings encountered during the creation of the container.
+	Warnings []string `json:"Warnings"`
+}