@@ -120,7 +120,7 @@ func (builder *Builder) clearTmp(containers, images map[string]struct{}) {

 	}

 }

-func (builder *Builder) Build(dockerfile io.Reader, stdout io.Writer) error {

+func (builder *Builder) Build(dockerfile io.Reader, stdout io.Writer) (*Image, error) {

 	var (

 		image, base   *Image

 		tmpContainers map[string]struct{} = make(map[string]struct{})

@@ -135,7 +135,7 @@ func (builder *Builder) Build(dockerfile io.Reader, stdout io.Writer) error {

 			if err == io.EOF {

 				break

 			}

-			return err

+			return nil, err

 		}

 		line = strings.TrimSpace(line)

 		// Skip comments and empty line

@@ -144,45 +144,45 @@ func (builder *Builder) Build(dockerfile io.Reader, stdout io.Writer) error {

 		}

 		tmp := strings.SplitN(line, "	", 2)

 		if len(tmp) != 2 {

-			return fmt.Errorf("Invalid Dockerfile format")

+			return nil, fmt.Errorf("Invalid Dockerfile format")

 		}

 		switch tmp[0] {

 		case "from":

 			fmt.Fprintf(stdout, "FROM %s\n", tmp[1])

 			image, err = builder.runtime.repositories.LookupImage(tmp[1])

 			if err != nil {

-				return err

+				return nil, err

 			}

 			break

 		case "run":

 			fmt.Fprintf(stdout, "RUN %s\n", tmp[1])

 			if image == nil {

-				return fmt.Errorf("Please provide a source image with `from` prior to run")

+				return nil, fmt.Errorf("Please provide a source image with `from` prior to run")

 			}

 			config, err := ParseRun([]string{image.Id, "/bin/sh", "-c", tmp[1]}, nil, builder.runtime.capabilities)

 			if err != nil {

-				return err

+				return nil, err

 			}

 			// Create the container and start it

 			c, err := builder.Create(config)

 			if err != nil {

-				return err

+				return nil, err

 			}

 			if err := c.Start(); err != nil {

-				return err

+				return nil, err

 			}

 			tmpContainers[c.Id] = struct{}{}

 			// Wait for it to finish

 			if result := c.Wait(); result != 0 {

-				return fmt.Errorf("!!! '%s' return non-zero exit code '%d'. Aborting.", tmp[1], result)

+				return nil, fmt.Errorf("!!! '%s' return non-zero exit code '%d'. Aborting.", tmp[1], result)

 			}

 			// Commit the container

 			base, err = builder.Commit(c, "", "", "", "")

 			if err != nil {

-				return err

+				return nil, err

 			}

 			tmpImages[base.Id] = struct{}{}

@@ -194,45 +194,45 @@ func (builder *Builder) Build(dockerfile io.Reader, stdout io.Writer) error {

 			break

 		case "copy":

 			if image == nil {

-				return fmt.Errorf("Please provide a source image with `from` prior to copy")

+				return nil, fmt.Errorf("Please provide a source image with `from` prior to copy")

 			}

 			tmp2 := strings.SplitN(tmp[1], " ", 2)

 			if len(tmp) != 2 {

-				return fmt.Errorf("Invalid COPY format")

+				return nil, fmt.Errorf("Invalid COPY format")

 			}

 			fmt.Fprintf(stdout, "COPY %s to %s in %s\n", tmp2[0], tmp2[1], base.ShortId())

 			file, err := Download(tmp2[0], stdout)

 			if err != nil {

-				return err

+				return nil, err

 			}

 			defer file.Body.Close()

 			config, err := ParseRun([]string{base.Id, "echo", "insert", tmp2[0], tmp2[1]}, nil, builder.runtime.capabilities)

 			if err != nil {

-				return err

+				return nil, err

 			}

 			c, err := builder.Create(config)

 			if err != nil {

-				return err

+				return nil, err

 			}

 			if err := c.Start(); err != nil {

-				return err

+				return nil, err

 			}

 			// Wait for echo to finish

 			if result := c.Wait(); result != 0 {

-				return fmt.Errorf("!!! '%s' return non-zero exit code '%d'. Aborting.", tmp[1], result)

+				return nil, fmt.Errorf("!!! '%s' return non-zero exit code '%d'. Aborting.", tmp[1], result)

 			}

 			if err := c.Inject(file.Body, tmp2[1]); err != nil {

-				return err

+				return nil, err

 			}

 			base, err = builder.Commit(c, "", "", "", "")

 			if err != nil {

-				return err

+				return nil, err

 			}

 			fmt.Fprintf(stdout, "===> %s\n", base.ShortId())

 			break

@@ -252,5 +252,5 @@ func (builder *Builder) Build(dockerfile io.Reader, stdout io.Writer) error {

 	} else {

 		fmt.Fprintf(stdout, "An error occured during the build\n")

 	}

-	return nil

+	return base, nil

 }

@@ -136,7 +136,12 @@ func (srv *Server) CmdBuild(stdin io.ReadCloser, stdout rcli.DockerConn, args ..

 	} else {

 		file = stdin

 	}

-	return NewBuilder(srv.runtime).Build(file, stdout)

+	img, err := NewBuilder(srv.runtime).Build(file, stdout)

+	if err != nil {

+		return err

+	}

+	fmt.Fprintf(stdout, "%s\n", img.ShortId())

+	return nil

 }

 // 'docker login': login / register a user to registry service.

@@ -154,6 +154,13 @@ func SelfPath() string {

 	return path

 }

+type nopWriter struct {

+}

+

+func (w *nopWriter) Write(buf []byte) (int, error) {

+	return len(buf), nil

+}

+

 type nopWriteCloser struct {

 	io.Writer

 }