'docker commit' can optionally tag the new image into a repository

commands.go

@@ -531,33 +531,22 @@ func (srv *Server) CmdPs(stdin io.ReadCloser, stdout io.Writer, args ...string)
 
 func (srv *Server) CmdCommit(stdin io.ReadCloser, stdout io.Writer, args ...string) error {
 	cmd := rcli.Subcmd(stdout,
-		"commit", "[OPTIONS] CONTAINER [DEST]",
+		"commit", "[OPTIONS] CONTAINER [REPOSITORY [TAG]]",
 		"Create a new image from a container's changes")
 	if err := cmd.Parse(args); err != nil {
 		return nil
 	}
-	containerName, imgName := cmd.Arg(0), cmd.Arg(1)
+	containerName, repository, tag := cmd.Arg(0), cmd.Arg(1), cmd.Arg(2)
-	if containerName == "" || imgName == "" {
+	if containerName == "" {
 		cmd.Usage()
 		return nil
 	}
-	if container := srv.runtime.Get(containerName); container != nil {
+	img, err := srv.runtime.Commit(containerName, repository, tag)
-		// FIXME: freeze the container before copying it to avoid data corruption?
+	if err != nil {
-		// FIXME: this shouldn't be in commands.
+		return err
-		rwTar, err := container.ExportRw()
-		if err != nil {
-			return err
-		}
-		// Create a new image from the container's base layers + a new layer from container changes
-		img, err := srv.runtime.graph.Create(rwTar, container.Image, "")
-		if err != nil {
-			return err
-		}
-
-		fmt.Fprintln(stdout, img.Id)
-		return nil
 	}
-	return errors.New("No such container: " + containerName)
+	fmt.Fprintln(stdout, img.Id)
+	return nil
 }
 
 func (srv *Server) CmdExport(stdin io.ReadCloser, stdout io.Writer, args ...string) error {

runtime.go

@@ -200,6 +200,33 @@ func (runtime *Runtime) Destroy(container *Container) error {
 	return nil
 }
 
+// Commit creates a new filesystem image from the current state of a container.
+// The image can optionally be tagged into a repository
+func (runtime *Runtime) Commit(id, repository, tag string) (*Image, error) {
+	container := runtime.Get(id)
+	if container == nil {
+		return nil, fmt.Errorf("No such container: %s", id)
+	}
+	// FIXME: freeze the container before copying it to avoid data corruption?
+	// FIXME: this shouldn't be in commands.
+	rwTar, err := container.ExportRw()
+	if err != nil {
+		return nil, err
+	}
+	// Create a new image from the container's base layers + a new layer from container changes
+	img, err := runtime.graph.Create(rwTar, container.Image, "")
+	if err != nil {
+		return nil, err
+	}
+	// Register the image if needed
+	if repository != "" {
+		if err := runtime.repositories.Set(repository, tag, img.Id); err != nil {
+			return img, err
+		}
+	}
+	return img, nil
+}
+
 func (runtime *Runtime) restore() error {
 	dir, err := ioutil.ReadDir(runtime.repository)
 	if err != nil {