@@ -33,6 +33,7 @@ import (

 	"github.com/docker/docker/nat"

 	"github.com/docker/docker/opts"

 	"github.com/docker/docker/pkg/archive"

+	"github.com/docker/docker/pkg/common"

 	"github.com/docker/docker/pkg/fileutils"

 	"github.com/docker/docker/pkg/homedir"

 	flag "github.com/docker/docker/pkg/mflag"

@@ -1075,7 +1076,7 @@ func (cli *DockerCli) CmdHistory(args ...string) error {

 			if *noTrunc {

 				fmt.Fprintf(w, "%s\t", outID)

 			} else {

-				fmt.Fprintf(w, "%s\t", utils.TruncateID(outID))

+				fmt.Fprintf(w, "%s\t", common.TruncateID(outID))

 			}

 			fmt.Fprintf(w, "%s ago\t", units.HumanDuration(time.Now().UTC().Sub(time.Unix(out.GetInt64("Created"), 0))))

@@ -1090,7 +1091,7 @@ func (cli *DockerCli) CmdHistory(args ...string) error {

 			if *noTrunc {

 				fmt.Fprintln(w, outID)

 			} else {

-				fmt.Fprintln(w, utils.TruncateID(outID))

+				fmt.Fprintln(w, common.TruncateID(outID))

 			}

 		}

 	}

@@ -1384,7 +1385,7 @@ func (cli *DockerCli) CmdImages(args ...string) error {

 			}

 			if matchName != "" {

-				if matchName == image.Get("Id") || matchName == utils.TruncateID(image.Get("Id")) {

+				if matchName == image.Get("Id") || matchName == common.TruncateID(image.Get("Id")) {

 					startImage = image

 				}

@@ -1453,7 +1454,7 @@ func (cli *DockerCli) CmdImages(args ...string) error {

 				repo, tag := parsers.ParseRepositoryTag(repotag)

 				outID := out.Get("Id")

 				if !*noTrunc {

-					outID = utils.TruncateID(outID)

+					outID = common.TruncateID(outID)

 				}

 				if !*quiet {

@@ -1508,8 +1509,8 @@ func (cli *DockerCli) printVizNode(noTrunc bool, image *engine.Env, prefix strin

 		imageID = image.Get("Id")

 		parentID = image.Get("ParentId")

 	} else {

-		imageID = utils.TruncateID(image.Get("Id"))

-		parentID = utils.TruncateID(image.Get("ParentId"))

+		imageID = common.TruncateID(image.Get("Id"))

+		parentID = common.TruncateID(image.Get("ParentId"))

 	}

 	if parentID == "" {

 		fmt.Fprintf(cli.out, " base -> \"%s\" [style=invis]\n", imageID)

@@ -1528,7 +1529,7 @@ func (cli *DockerCli) printTreeNode(noTrunc bool, image *engine.Env, prefix stri

 	if noTrunc {

 		imageID = image.Get("Id")

 	} else {

-		imageID = utils.TruncateID(image.Get("Id"))

+		imageID = common.TruncateID(image.Get("Id"))

 	}

 	fmt.Fprintf(cli.out, "%s%s Virtual Size: %s", prefix, imageID, units.HumanSize(float64(image.GetInt64("VirtualSize"))))

@@ -1636,7 +1637,7 @@ func (cli *DockerCli) CmdPs(args ...string) error {

 		outID := out.Get("Id")

 		if !*noTrunc {

-			outID = utils.TruncateID(outID)

+			outID = common.TruncateID(outID)

 		}

 		if *quiet {

@@ -32,6 +32,7 @@ import (

 	"github.com/docker/docker/builder/parser"

 	"github.com/docker/docker/daemon"

 	"github.com/docker/docker/engine"

+	"github.com/docker/docker/pkg/common"

 	"github.com/docker/docker/pkg/fileutils"

 	"github.com/docker/docker/pkg/symlink"

 	"github.com/docker/docker/pkg/tarsum"

@@ -155,7 +156,7 @@ func (b *Builder) Run(context io.Reader) (string, error) {

 			}

 			return "", err

 		}

-		fmt.Fprintf(b.OutStream, " ---> %s\n", utils.TruncateID(b.image))

+		fmt.Fprintf(b.OutStream, " ---> %s\n", common.TruncateID(b.image))

 		if b.Remove {

 			b.clearTmp()

 		}

@@ -165,7 +166,7 @@ func (b *Builder) Run(context io.Reader) (string, error) {

 		return "", fmt.Errorf("No image was generated. Is your Dockerfile empty?")

 	}

-	fmt.Fprintf(b.OutStream, "Successfully built %s\n", utils.TruncateID(b.image))

+	fmt.Fprintf(b.OutStream, "Successfully built %s\n", common.TruncateID(b.image))

 	return b.image, nil

 }

@@ -25,6 +25,7 @@ import (

 	imagepkg "github.com/docker/docker/image"

 	"github.com/docker/docker/pkg/archive"

 	"github.com/docker/docker/pkg/chrootarchive"

+	"github.com/docker/docker/pkg/common"

 	"github.com/docker/docker/pkg/ioutils"

 	"github.com/docker/docker/pkg/parsers"

 	"github.com/docker/docker/pkg/symlink"

@@ -531,7 +532,7 @@ func (b *Builder) create() (*daemon.Container, error) {

 	}

 	b.TmpContainers[c.ID] = struct{}{}

-	fmt.Fprintf(b.OutStream, " ---> Running in %s\n", utils.TruncateID(c.ID))

+	fmt.Fprintf(b.OutStream, " ---> Running in %s\n", common.TruncateID(c.ID))

 	if len(config.Cmd) > 0 {

 		// override the entry point that may have been picked up from the base image

@@ -713,11 +714,11 @@ func (b *Builder) clearTmp() {

 		}

 		if err := b.Daemon.Rm(tmp); err != nil {

-			fmt.Fprintf(b.OutStream, "Error removing intermediate container %s: %s\n", utils.TruncateID(c), err.Error())

+			fmt.Fprintf(b.OutStream, "Error removing intermediate container %s: %s\n", common.TruncateID(c), err.Error())

 			return

 		}

 		b.Daemon.DeleteVolumes(tmp.VolumePaths())

 		delete(b.TmpContainers, c)

-		fmt.Fprintf(b.OutStream, "Removing intermediate container %s\n", utils.TruncateID(c))

+		fmt.Fprintf(b.OutStream, "Removing intermediate container %s\n", common.TruncateID(c))

 	}

 }

@@ -25,6 +25,7 @@ import (

 	"github.com/docker/docker/nat"

 	"github.com/docker/docker/pkg/archive"

 	"github.com/docker/docker/pkg/broadcastwriter"

+	"github.com/docker/docker/pkg/common"

 	"github.com/docker/docker/pkg/ioutils"

 	"github.com/docker/docker/pkg/networkfs/etchosts"

 	"github.com/docker/docker/pkg/networkfs/resolvconf"

@@ -704,7 +705,7 @@ func (container *Container) Kill() error {

 	if _, err := container.WaitStop(10 * time.Second); err != nil {

 		// Ensure that we don't kill ourselves

 		if pid := container.GetPid(); pid != 0 {

-			log.Infof("Container %s failed to exit within 10 seconds of kill - trying direct SIGKILL", utils.TruncateID(container.ID))

+			log.Infof("Container %s failed to exit within 10 seconds of kill - trying direct SIGKILL", common.TruncateID(container.ID))

 			if err := syscall.Kill(pid, 9); err != nil {

 				if err != syscall.ESRCH {

 					return err

@@ -31,6 +31,7 @@ import (

 	"github.com/docker/docker/image"

 	"github.com/docker/docker/pkg/archive"

 	"github.com/docker/docker/pkg/broadcastwriter"

+	"github.com/docker/docker/pkg/common"

 	"github.com/docker/docker/pkg/graphdb"

 	"github.com/docker/docker/pkg/ioutils"

 	"github.com/docker/docker/pkg/namesgenerator"

@@ -511,7 +512,7 @@ func (daemon *Daemon) mergeAndVerifyConfig(config *runconfig.Config, img *image.

 func (daemon *Daemon) generateIdAndName(name string) (string, string, error) {

 	var (

 		err error

-		id  = utils.GenerateRandomID()

+		id  = common.GenerateRandomID()

 	)

 	if name == "" {

@@ -556,7 +557,7 @@ func (daemon *Daemon) reserveName(id, name string) (string, error) {

 			nameAsKnownByUser := strings.TrimPrefix(name, "/")

 			return "", fmt.Errorf(

 				"Conflict. The name %q is already in use by container %s. You have to delete (or rename) that container to be able to reuse that name.", nameAsKnownByUser,

-				utils.TruncateID(conflictingContainer.ID))

+				common.TruncateID(conflictingContainer.ID))

 		}

 	}

 	return name, nil

@@ -579,7 +580,7 @@ func (daemon *Daemon) generateNewName(id string) (string, error) {

 		return name, nil

 	}

-	name = "/" + utils.TruncateID(id)

+	name = "/" + common.TruncateID(id)

 	if _, err := daemon.containerGraph.Set(name, id); err != nil {

 		return "", err

 	}

@@ -12,10 +12,10 @@ import (

 	"github.com/docker/docker/daemon/execdriver/lxc"

 	"github.com/docker/docker/engine"

 	"github.com/docker/docker/pkg/broadcastwriter"

+	"github.com/docker/docker/pkg/common"

 	"github.com/docker/docker/pkg/ioutils"

 	"github.com/docker/docker/pkg/promise"

 	"github.com/docker/docker/runconfig"

-	"github.com/docker/docker/utils"

 )

 type execConfig struct {

@@ -141,7 +141,7 @@ func (d *Daemon) ContainerExecCreate(job *engine.Job) engine.Status {

 	}

 	execConfig := &execConfig{

-		ID:            utils.GenerateRandomID(),

+		ID:            common.GenerateRandomID(),

 		OpenStdin:     config.AttachStdin,

 		OpenStdout:    config.AttachStdout,

 		OpenStderr:    config.AttachStderr,

@@ -34,6 +34,7 @@ import (

 	"github.com/docker/docker/daemon/graphdriver"

 	"github.com/docker/docker/pkg/archive"

 	"github.com/docker/docker/pkg/chrootarchive"

+	"github.com/docker/docker/pkg/common"

 	mountpk "github.com/docker/docker/pkg/mount"

 	"github.com/docker/docker/utils"

 	"github.com/docker/libcontainer/label"

@@ -404,7 +405,7 @@ func (a *Driver) Cleanup() error {

 	for _, id := range ids {

 		if err := a.unmount(id); err != nil {

-			log.Errorf("Unmounting %s: %s", utils.TruncateID(id), err)

+			log.Errorf("Unmounting %s: %s", common.TruncateID(id), err)

 		}

 	}

@@ -7,8 +7,8 @@ import (

 	"github.com/docker/docker/engine"

 	"github.com/docker/docker/graph"

 	"github.com/docker/docker/image"

+	"github.com/docker/docker/pkg/common"

 	"github.com/docker/docker/pkg/parsers"

-	"github.com/docker/docker/utils"

 )

 func (daemon *Daemon) ImageDelete(job *engine.Job) engine.Status {

@@ -143,11 +143,11 @@ func (daemon *Daemon) canDeleteImage(imgID string, force bool) error {

 			if imgID == p.ID {

 				if container.IsRunning() {

 					if force {

-						return fmt.Errorf("Conflict, cannot force delete %s because the running container %s is using it, stop it and retry", utils.TruncateID(imgID), utils.TruncateID(container.ID))

+						return fmt.Errorf("Conflict, cannot force delete %s because the running container %s is using it, stop it and retry", common.TruncateID(imgID), common.TruncateID(container.ID))

 					}

-					return fmt.Errorf("Conflict, cannot delete %s because the running container %s is using it, stop it and use -f to force", utils.TruncateID(imgID), utils.TruncateID(container.ID))

+					return fmt.Errorf("Conflict, cannot delete %s because the running container %s is using it, stop it and use -f to force", common.TruncateID(imgID), common.TruncateID(container.ID))

 				} else if !force {

-					return fmt.Errorf("Conflict, cannot delete %s because the container %s is using it, use -f to force", utils.TruncateID(imgID), utils.TruncateID(container.ID))

+					return fmt.Errorf("Conflict, cannot delete %s because the container %s is using it, use -f to force", common.TruncateID(imgID), common.TruncateID(container.ID))

 				}

 			}

 			return nil

@@ -8,8 +8,8 @@ import (

 	log "github.com/Sirupsen/logrus"

 	"github.com/docker/docker/daemon/execdriver"

+	"github.com/docker/docker/pkg/common"

 	"github.com/docker/docker/runconfig"

-	"github.com/docker/docker/utils"

 )

 const defaultTimeIncrement = 100

@@ -230,7 +230,7 @@ func (m *containerMonitor) shouldRestart(exitCode int) bool {

 		// the default value of 0 for MaximumRetryCount means that we will not enforce a maximum count

 		if max := m.restartPolicy.MaximumRetryCount; max != 0 && m.failureCount > max {

 			log.Debugf("stopping restart of container %s because maximum failure could of %d has been reached",

-				utils.TruncateID(m.container.ID), max)

+				common.TruncateID(m.container.ID), max)

 			return false

 		}

@@ -17,6 +17,7 @@ import (

 	"github.com/docker/docker/daemon/graphdriver"

 	"github.com/docker/docker/image"

 	"github.com/docker/docker/pkg/archive"

+	"github.com/docker/docker/pkg/common"

 	"github.com/docker/docker/pkg/truncindex"

 	"github.com/docker/docker/runconfig"

 	"github.com/docker/docker/utils"

@@ -116,7 +117,7 @@ func (graph *Graph) Get(name string) (*image.Image, error) {

 // Create creates a new image and registers it in the graph.

 func (graph *Graph) Create(layerData archive.ArchiveReader, containerID, containerImage, comment, author string, containerConfig, config *runconfig.Config) (*image.Image, error) {

 	img := &image.Image{

-		ID:            utils.GenerateRandomID(),

+		ID:            common.GenerateRandomID(),

 		Comment:       comment,

 		Created:       time.Now().UTC(),

 		DockerVersion: dockerversion.VERSION,

@@ -209,14 +210,14 @@ func (graph *Graph) TempLayerArchive(id string, sf *utils.StreamFormatter, outpu

 	if err != nil {

 		return nil, err

 	}

-	progress := utils.ProgressReader(a, 0, output, sf, false, utils.TruncateID(id), "Buffering to disk")

+	progress := utils.ProgressReader(a, 0, output, sf, false, common.TruncateID(id), "Buffering to disk")

 	defer progress.Close()

 	return archive.NewTempArchive(progress, tmp)

 }

 // Mktemp creates a temporary sub-directory inside the graph's filesystem.

 func (graph *Graph) Mktemp(id string) (string, error) {

-	dir := path.Join(graph.Root, "_tmp", utils.GenerateRandomID())

+	dir := path.Join(graph.Root, "_tmp", common.GenerateRandomID())

 	if err := os.MkdirAll(dir, 0700); err != nil {

 		return "", err

 	}

@@ -13,6 +13,7 @@ import (

 	log "github.com/Sirupsen/logrus"

 	"github.com/docker/docker/engine"

 	"github.com/docker/docker/image"

+	"github.com/docker/docker/pkg/common"

 	"github.com/docker/docker/pkg/tarsum"

 	"github.com/docker/docker/registry"

 	"github.com/docker/docker/utils"

@@ -170,9 +171,9 @@ func (s *TagStore) pullRepository(r *registry.Session, out io.Writer, repoInfo *

 			// ensure no two downloads of the same image happen at the same time

 			if c, err := s.poolAdd("pull", "img:"+img.ID); err != nil {

 				if c != nil {

-					out.Write(sf.FormatProgress(utils.TruncateID(img.ID), "Layer already being pulled by another client. Waiting.", nil))

+					out.Write(sf.FormatProgress(common.TruncateID(img.ID), "Layer already being pulled by another client. Waiting.", nil))

 					<-c

-					out.Write(sf.FormatProgress(utils.TruncateID(img.ID), "Download complete", nil))

+					out.Write(sf.FormatProgress(common.TruncateID(img.ID), "Download complete", nil))

 				} else {

 					log.Debugf("Image (id: %s) pull is already running, skipping: %v", img.ID, err)

 				}

@@ -183,12 +184,12 @@ func (s *TagStore) pullRepository(r *registry.Session, out io.Writer, repoInfo *

 			}

 			defer s.poolRemove("pull", "img:"+img.ID)

-			out.Write(sf.FormatProgress(utils.TruncateID(img.ID), fmt.Sprintf("Pulling image (%s) from %s", img.Tag, repoInfo.CanonicalName), nil))

+			out.Write(sf.FormatProgress(common.TruncateID(img.ID), fmt.Sprintf("Pulling image (%s) from %s", img.Tag, repoInfo.CanonicalName), nil))

 			success := false

 			var lastErr, err error

 			var is_downloaded bool

 			for _, ep := range repoInfo.Index.Mirrors {

-				out.Write(sf.FormatProgress(utils.TruncateID(img.ID), fmt.Sprintf("Pulling image (%s) from %s, mirror: %s", img.Tag, repoInfo.CanonicalName, ep), nil))

+				out.Write(sf.FormatProgress(common.TruncateID(img.ID), fmt.Sprintf("Pulling image (%s) from %s, mirror: %s", img.Tag, repoInfo.CanonicalName, ep), nil))

 				if is_downloaded, err = s.pullImage(r, out, img.ID, ep, repoData.Tokens, sf); err != nil {

 					// Don't report errors when pulling from mirrors.

 					log.Debugf("Error pulling image (%s) from %s, mirror: %s, %s", img.Tag, repoInfo.CanonicalName, ep, err)

@@ -200,12 +201,12 @@ func (s *TagStore) pullRepository(r *registry.Session, out io.Writer, repoInfo *

 			}

 			if !success {

 				for _, ep := range repoData.Endpoints {

-					out.Write(sf.FormatProgress(utils.TruncateID(img.ID), fmt.Sprintf("Pulling image (%s) from %s, endpoint: %s", img.Tag, repoInfo.CanonicalName, ep), nil))

+					out.Write(sf.FormatProgress(common.TruncateID(img.ID), fmt.Sprintf("Pulling image (%s) from %s, endpoint: %s", img.Tag, repoInfo.CanonicalName, ep), nil))

 					if is_downloaded, err = s.pullImage(r, out, img.ID, ep, repoData.Tokens, sf); err != nil {

 						// It's not ideal that only the last error is returned, it would be better to concatenate the errors.

 						// As the error is also given to the output stream the user will see the error.

 						lastErr = err

-						out.Write(sf.FormatProgress(utils.TruncateID(img.ID), fmt.Sprintf("Error pulling image (%s) from %s, endpoint: %s, %s", img.Tag, repoInfo.CanonicalName, ep, err), nil))

+						out.Write(sf.FormatProgress(common.TruncateID(img.ID), fmt.Sprintf("Error pulling image (%s) from %s, endpoint: %s, %s", img.Tag, repoInfo.CanonicalName, ep, err), nil))

 						continue

 					}

 					layers_downloaded = layers_downloaded || is_downloaded

@@ -215,13 +216,13 @@ func (s *TagStore) pullRepository(r *registry.Session, out io.Writer, repoInfo *

 			}

 			if !success {

 				err := fmt.Errorf("Error pulling image (%s) from %s, %v", img.Tag, repoInfo.CanonicalName, lastErr)

-				out.Write(sf.FormatProgress(utils.TruncateID(img.ID), err.Error(), nil))

+				out.Write(sf.FormatProgress(common.TruncateID(img.ID), err.Error(), nil))

 				if parallel {

 					errors <- err

 					return

 				}

 			}

-			out.Write(sf.FormatProgress(utils.TruncateID(img.ID), "Download complete", nil))

+			out.Write(sf.FormatProgress(common.TruncateID(img.ID), "Download complete", nil))

 			if parallel {

 				errors <- nil

@@ -268,7 +269,7 @@ func (s *TagStore) pullImage(r *registry.Session, out io.Writer, imgID, endpoint

 	if err != nil {

 		return false, err

 	}

-	out.Write(sf.FormatProgress(utils.TruncateID(imgID), "Pulling dependent layers", nil))

+	out.Write(sf.FormatProgress(common.TruncateID(imgID), "Pulling dependent layers", nil))

 	// FIXME: Try to stream the images?

 	// FIXME: Launch the getRemoteImage() in goroutines

@@ -284,7 +285,7 @@ func (s *TagStore) pullImage(r *registry.Session, out io.Writer, imgID, endpoint

 		defer s.poolRemove("pull", "layer:"+id)

 		if !s.graph.Exists(id) {

-			out.Write(sf.FormatProgress(utils.TruncateID(id), "Pulling metadata", nil))

+			out.Write(sf.FormatProgress(common.TruncateID(id), "Pulling metadata", nil))

 			var (

 				imgJSON []byte

 				imgSize int

@@ -295,7 +296,7 @@ func (s *TagStore) pullImage(r *registry.Session, out io.Writer, imgID, endpoint

 			for j := 1; j <= retries; j++ {

 				imgJSON, imgSize, err = r.GetRemoteImageJSON(id, endpoint, token)

 				if err != nil && j == retries {

-					out.Write(sf.FormatProgress(utils.TruncateID(id), "Error pulling dependent layers", nil))

+					out.Write(sf.FormatProgress(common.TruncateID(id), "Error pulling dependent layers", nil))

 					return layers_downloaded, err

 				} else if err != nil {

 					time.Sleep(time.Duration(j) * 500 * time.Millisecond)

@@ -304,7 +305,7 @@ func (s *TagStore) pullImage(r *registry.Session, out io.Writer, imgID, endpoint

 				img, err = image.NewImgJSON(imgJSON)

 				layers_downloaded = true

 				if err != nil && j == retries {

-					out.Write(sf.FormatProgress(utils.TruncateID(id), "Error pulling dependent layers", nil))

+					out.Write(sf.FormatProgress(common.TruncateID(id), "Error pulling dependent layers", nil))

 					return layers_downloaded, fmt.Errorf("Failed to parse json: %s", err)

 				} else if err != nil {

 					time.Sleep(time.Duration(j) * 500 * time.Millisecond)

@@ -320,7 +321,7 @@ func (s *TagStore) pullImage(r *registry.Session, out io.Writer, imgID, endpoint

 				if j > 1 {

 					status = fmt.Sprintf("Pulling fs layer [retries: %d]", j)

 				}

-				out.Write(sf.FormatProgress(utils.TruncateID(id), status, nil))

+				out.Write(sf.FormatProgress(common.TruncateID(id), status, nil))

 				layer, err := r.GetRemoteImageLayer(img.ID, endpoint, token, int64(imgSize))

 				if uerr, ok := err.(*url.Error); ok {

 					err = uerr.Err

@@ -329,26 +330,26 @@ func (s *TagStore) pullImage(r *registry.Session, out io.Writer, imgID, endpoint

 					time.Sleep(time.Duration(j) * 500 * time.Millisecond)

 					continue

 				} else if err != nil {

-					out.Write(sf.FormatProgress(utils.TruncateID(id), "Error pulling dependent layers", nil))

+					out.Write(sf.FormatProgress(common.TruncateID(id), "Error pulling dependent layers", nil))

 					return layers_downloaded, err

 				}

 				layers_downloaded = true

 				defer layer.Close()

 				err = s.graph.Register(img,

-					utils.ProgressReader(layer, imgSize, out, sf, false, utils.TruncateID(id), "Downloading"))

+					utils.ProgressReader(layer, imgSize, out, sf, false, common.TruncateID(id), "Downloading"))

 				if terr, ok := err.(net.Error); ok && terr.Timeout() && j < retries {

 					time.Sleep(time.Duration(j) * 500 * time.Millisecond)

 					continue

 				} else if err != nil {

-					out.Write(sf.FormatProgress(utils.TruncateID(id), "Error downloading dependent layers", nil))

+					out.Write(sf.FormatProgress(common.TruncateID(id), "Error downloading dependent layers", nil))

 					return layers_downloaded, err

 				} else {

 					break

 				}

 			}

 		}

-		out.Write(sf.FormatProgress(utils.TruncateID(id), "Download complete", nil))

+		out.Write(sf.FormatProgress(common.TruncateID(id), "Download complete", nil))

 	}

 	return layers_downloaded, nil

 }

@@ -463,16 +464,16 @@ func (s *TagStore) pullV2Tag(eng *engine.Engine, r *registry.Session, out io.Wri

 			return false, fmt.Errorf("expected 2 parts in the sumStr, got %#v", chunks)

 		}

 		sumType, checksum := chunks[0], chunks[1]

-		out.Write(sf.FormatProgress(utils.TruncateID(img.ID), "Pulling fs layer", nil))

+		out.Write(sf.FormatProgress(common.TruncateID(img.ID), "Pulling fs layer", nil))

 		downloadFunc := func(di *downloadInfo) error {

 			log.Debugf("pulling blob %q to V1 img %s", sumStr, img.ID)

 			if c, err := s.poolAdd("pull", "img:"+img.ID); err != nil {

 				if c != nil {

-					out.Write(sf.FormatProgress(utils.TruncateID(img.ID), "Layer already being pulled by another client. Waiting.", nil))

+					out.Write(sf.FormatProgress(common.TruncateID(img.ID), "Layer already being pulled by another client. Waiting.", nil))

 					<-c

-					out.Write(sf.FormatProgress(utils.TruncateID(img.ID), "Download complete", nil))

+					out.Write(sf.FormatProgress(common.TruncateID(img.ID), "Download complete", nil))

 				} else {

 					log.Debugf("Image (id: %s) pull is already running, skipping: %v", img.ID, err)

 				}

@@ -495,16 +496,16 @@ func (s *TagStore) pullV2Tag(eng *engine.Engine, r *registry.Session, out io.Wri

 					return fmt.Errorf("unable to wrap image blob reader with TarSum: %s", err)

 				}

-				io.Copy(tmpFile, utils.ProgressReader(ioutil.NopCloser(tarSumReader), int(l), out, sf, false, utils.TruncateID(img.ID), "Downloading"))

+				io.Copy(tmpFile, utils.ProgressReader(ioutil.NopCloser(tarSumReader), int(l), out, sf, false, common.TruncateID(img.ID), "Downloading"))

-				out.Write(sf.FormatProgress(utils.TruncateID(img.ID), "Verifying Checksum", nil))

+				out.Write(sf.FormatProgress(common.TruncateID(img.ID), "Verifying Checksum", nil))

 				if finalChecksum := tarSumReader.Sum(nil); !strings.EqualFold(finalChecksum, sumStr) {

 					log.Infof("Image verification failed: checksum mismatch - expected %q but got %q", sumStr, finalChecksum)

 					verified = false

 				}

-				out.Write(sf.FormatProgress(utils.TruncateID(img.ID), "Download complete", nil))

+				out.Write(sf.FormatProgress(common.TruncateID(img.ID), "Download complete", nil))

 				log.Debugf("Downloaded %s to tempfile %s", img.ID, tmpFile.Name())

 				di.tmpFile = tmpFile

@@ -545,17 +546,17 @@ func (s *TagStore) pullV2Tag(eng *engine.Engine, r *registry.Session, out io.Wri

 			d.tmpFile.Seek(0, 0)

 			if d.tmpFile != nil {

 				err = s.graph.Register(d.img,

-					utils.ProgressReader(d.tmpFile, int(d.length), out, sf, false, utils.TruncateID(d.img.ID), "Extracting"))

+					utils.ProgressReader(d.tmpFile, int(d.length), out, sf, false, common.TruncateID(d.img.ID), "Extracting"))

 				if err != nil {

 					return false, err

 				}

 				// FIXME: Pool release here for parallel tag pull (ensures any downloads block until fully extracted)

 			}

-			out.Write(sf.FormatProgress(utils.TruncateID(d.img.ID), "Pull complete", nil))

+			out.Write(sf.FormatProgress(common.TruncateID(d.img.ID), "Pull complete", nil))

 			layersDownloaded = true

 		} else {

-			out.Write(sf.FormatProgress(utils.TruncateID(d.img.ID), "Already exists", nil))

+			out.Write(sf.FormatProgress(common.TruncateID(d.img.ID), "Already exists", nil))

 		}

 	}

@@ -14,6 +14,7 @@ import (

 	log "github.com/Sirupsen/logrus"

 	"github.com/docker/docker/engine"

 	"github.com/docker/docker/image"

+	"github.com/docker/docker/pkg/common"

 	"github.com/docker/docker/registry"

 	"github.com/docker/docker/utils"

 	"github.com/docker/libtrust"

@@ -129,7 +130,7 @@ func lookupImageOnEndpoint(wg *sync.WaitGroup, r *registry.Session, out io.Write

 			imagesToPush <- image.id

 			continue

 		}

-		out.Write(sf.FormatStatus("", "Image %s already pushed, skipping", utils.TruncateID(image.id)))

+		out.Write(sf.FormatStatus("", "Image %s already pushed, skipping", common.TruncateID(image.id)))

 	}

 }

@@ -181,7 +182,7 @@ func (s *TagStore) pushImageToEndpoint(endpoint string, out io.Writer, remoteNam

 			}

 		}

 		for _, tag := range tags[id] {

-			out.Write(sf.FormatStatus("", "Pushing tag for rev [%s] on {%s}", utils.TruncateID(id), endpoint+"repositories/"+remoteName+"/tags/"+tag))

+			out.Write(sf.FormatStatus("", "Pushing tag for rev [%s] on {%s}", common.TruncateID(id), endpoint+"repositories/"+remoteName+"/tags/"+tag))

 			if err := r.PushRegistryTag(remoteName, id, tag, endpoint, repo.Tokens); err != nil {

 				return err

 			}

@@ -234,7 +235,7 @@ func (s *TagStore) pushImage(r *registry.Session, out io.Writer, imgID, ep strin

 	if err != nil {

 		return "", fmt.Errorf("Cannot retrieve the path for {%s}: %s", imgID, err)

 	}

-	out.Write(sf.FormatProgress(utils.TruncateID(imgID), "Pushing", nil))

+	out.Write(sf.FormatProgress(common.TruncateID(imgID), "Pushing", nil))

 	imgData := &registry.ImgData{

 		ID: imgID,

@@ -243,7 +244,7 @@ func (s *TagStore) pushImage(r *registry.Session, out io.Writer, imgID, ep strin

 	// Send the json

 	if err := r.PushImageJSONRegistry(imgData, jsonRaw, ep, token); err != nil {

 		if err == registry.ErrAlreadyExists {

-			out.Write(sf.FormatProgress(utils.TruncateID(imgData.ID), "Image already pushed, skipping", nil))

+			out.Write(sf.FormatProgress(common.TruncateID(imgData.ID), "Image already pushed, skipping", nil))

 			return "", nil

 		}

 		return "", err

@@ -258,7 +259,7 @@ func (s *TagStore) pushImage(r *registry.Session, out io.Writer, imgID, ep strin

 	// Send the layer

 	log.Debugf("rendered layer for %s of [%d] size", imgData.ID, layerData.Size)

-	checksum, checksumPayload, err := r.PushImageLayerRegistry(imgData.ID, utils.ProgressReader(layerData, int(layerData.Size), out, sf, false, utils.TruncateID(imgData.ID), "Pushing"), ep, token, jsonRaw)

+	checksum, checksumPayload, err := r.PushImageLayerRegistry(imgData.ID, utils.ProgressReader(layerData, int(layerData.Size), out, sf, false, common.TruncateID(imgData.ID), "Pushing"), ep, token, jsonRaw)

 	if err != nil {

 		return "", err

 	}

@@ -269,7 +270,7 @@ func (s *TagStore) pushImage(r *registry.Session, out io.Writer, imgID, ep strin

 		return "", err

 	}

-	out.Write(sf.FormatProgress(utils.TruncateID(imgData.ID), "Image successfully pushed", nil))

+	out.Write(sf.FormatProgress(common.TruncateID(imgData.ID), "Image successfully pushed", nil))

 	return imgData.Checksum, nil

 }

@@ -359,7 +360,7 @@ func (s *TagStore) pushV2Repository(r *registry.Session, eng *engine.Engine, out

 			// Call mount blob

 			exists, err := r.HeadV2ImageBlob(endpoint, repoInfo.RemoteName, sumParts[0], manifestSum, auth)

 			if err != nil {

-				out.Write(sf.FormatProgress(utils.TruncateID(img.ID), "Image push failed", nil))

+				out.Write(sf.FormatProgress(common.TruncateID(img.ID), "Image push failed", nil))

 				return err

 			}

@@ -368,7 +369,7 @@ func (s *TagStore) pushV2Repository(r *registry.Session, eng *engine.Engine, out

 					return err

 				}

 			} else {

-				out.Write(sf.FormatProgress(utils.TruncateID(img.ID), "Image already exists", nil))

+				out.Write(sf.FormatProgress(common.TruncateID(img.ID), "Image already exists", nil))

 			}

 		}

@@ -382,7 +383,7 @@ func (s *TagStore) pushV2Repository(r *registry.Session, eng *engine.Engine, out

 // PushV2Image pushes the image content to the v2 registry, first buffering the contents to disk

 func (s *TagStore) pushV2Image(r *registry.Session, img *image.Image, endpoint *registry.Endpoint, imageName, sumType, sumStr string, sf *utils.StreamFormatter, out io.Writer, auth *registry.RequestAuthorization) error {

-	out.Write(sf.FormatProgress(utils.TruncateID(img.ID), "Buffering to Disk", nil))

+	out.Write(sf.FormatProgress(common.TruncateID(img.ID), "Buffering to Disk", nil))

 	image, err := s.graph.Get(img.ID)

 	if err != nil {

@@ -411,11 +412,11 @@ func (s *TagStore) pushV2Image(r *registry.Session, img *image.Image, endpoint *

 	// Send the layer

 	log.Debugf("rendered layer for %s of [%d] size", img.ID, size)

-	if err := r.PutV2ImageBlob(endpoint, imageName, sumType, sumStr, utils.ProgressReader(tf, int(size), out, sf, false, utils.TruncateID(img.ID), "Pushing"), auth); err != nil {

-		out.Write(sf.FormatProgress(utils.TruncateID(img.ID), "Image push failed", nil))

+	if err := r.PutV2ImageBlob(endpoint, imageName, sumType, sumStr, utils.ProgressReader(tf, int(size), out, sf, false, common.TruncateID(img.ID), "Pushing"), auth); err != nil {

+		out.Write(sf.FormatProgress(common.TruncateID(img.ID), "Image push failed", nil))

 		return err

 	}

-	out.Write(sf.FormatProgress(utils.TruncateID(img.ID), "Image successfully pushed", nil))

+	out.Write(sf.FormatProgress(common.TruncateID(img.ID), "Image successfully pushed", nil))

 	return nil

 }

@@ -12,9 +12,9 @@ import (

 	"sync"

 	"github.com/docker/docker/image"

+	"github.com/docker/docker/pkg/common"

 	"github.com/docker/docker/pkg/parsers"

 	"github.com/docker/docker/registry"

-	"github.com/docker/docker/utils"

 	"github.com/docker/libtrust"

 )

@@ -148,7 +148,7 @@ func (store *TagStore) ImageName(id string) string {

 	if names, exists := store.ByID()[id]; exists && len(names) > 0 {

 		return names[0]

 	}

-	return utils.TruncateID(id)

+	return common.TruncateID(id)

 }

 func (store *TagStore) DeleteAll(id string) error {

@@ -274,7 +274,7 @@ func (store *TagStore) GetRepoRefs() map[string][]string {

 	for name, repository := range store.Repositories {

 		for tag, id := range repository {

-			shortID := utils.TruncateID(id)

+			shortID := common.TruncateID(id)

 			reporefs[shortID] = append(reporefs[shortID], fmt.Sprintf("%s:%s", name, tag))

 		}

 	}

@@ -12,8 +12,8 @@ import (

 	log "github.com/Sirupsen/logrus"

 	"github.com/docker/docker/api/client"

 	"github.com/docker/docker/daemon"

+	"github.com/docker/docker/pkg/common"

 	"github.com/docker/docker/pkg/term"

-	"github.com/docker/docker/utils"

 	"github.com/kr/pty"

 )

@@ -286,7 +286,7 @@ func TestAttachDetachTruncatedID(t *testing.T) {

 	ch := make(chan struct{})

 	go func() {

 		defer close(ch)

-		if err := cli.CmdAttach(utils.TruncateID(container.ID)); err != nil {

+		if err := cli.CmdAttach(common.TruncateID(container.ID)); err != nil {

 			if err != io.ErrClosedPipe {

 				t.Fatal(err)

 			}

@@ -7,6 +7,7 @@ import (

 	"github.com/docker/docker/graph"

 	"github.com/docker/docker/image"

 	"github.com/docker/docker/pkg/archive"

+	"github.com/docker/docker/pkg/common"

 	"github.com/docker/docker/utils"

 	"io"

 	"io/ioutil"

@@ -69,7 +70,7 @@ func TestInterruptedRegister(t *testing.T) {

 	defer nukeGraph(graph)

 	badArchive, w := io.Pipe() // Use a pipe reader as a fake archive which never yields data

 	image := &image.Image{

-		ID:      utils.GenerateRandomID(),

+		ID:      common.GenerateRandomID(),

 		Comment: "testing",

 		Created: time.Now(),

 	}

@@ -129,7 +130,7 @@ func TestRegister(t *testing.T) {

 		t.Fatal(err)

 	}

 	image := &image.Image{

-		ID:      utils.GenerateRandomID(),

+		ID:      common.GenerateRandomID(),

 		Comment: "testing",

 		Created: time.Now(),

 	}

@@ -159,7 +160,7 @@ func TestDeletePrefix(t *testing.T) {

 	graph, _ := tempGraph(t)

 	defer nukeGraph(graph)

 	img := createTestImage(graph, t)

-	if err := graph.Delete(utils.TruncateID(img.ID)); err != nil {

+	if err := graph.Delete(common.TruncateID(img.ID)); err != nil {

 		t.Fatal(err)

 	}

 	assertNImages(graph, t, 0)

@@ -245,19 +246,19 @@ func TestByParent(t *testing.T) {

 	graph, _ := tempGraph(t)

 	defer nukeGraph(graph)

 	parentImage := &image.Image{

-		ID:      utils.GenerateRandomID(),

+		ID:      common.GenerateRandomID(),

 		Comment: "parent",

 		Created: time.Now(),

 		Parent:  "",

 	}

 	childImage1 := &image.Image{

-		ID:      utils.GenerateRandomID(),

+		ID:      common.GenerateRandomID(),

 		Comment: "child1",

 		Created: time.Now(),

 		Parent:  parentImage.ID,

 	}

 	childImage2 := &image.Image{

-		ID:      utils.GenerateRandomID(),

+		ID:      common.GenerateRandomID(),

 		Comment: "child2",

 		Created: time.Now(),

 		Parent:  parentImage.ID,

@@ -22,6 +22,7 @@ import (

 	"github.com/docker/docker/engine"

 	"github.com/docker/docker/image"

 	"github.com/docker/docker/nat"

+	"github.com/docker/docker/pkg/common"

 	"github.com/docker/docker/pkg/ioutils"

 	"github.com/docker/docker/pkg/reexec"

 	"github.com/docker/docker/runconfig"

@@ -305,7 +306,7 @@ func TestDaemonCreate(t *testing.T) {

 		&runconfig.HostConfig{},

 		"conflictname",

 	)

-	if _, _, err := daemon.Create(&runconfig.Config{Image: GetTestImage(daemon).ID, Cmd: []string{"ls", "-al"}}, &runconfig.HostConfig{}, testContainer.Name); err == nil || !strings.Contains(err.Error(), utils.TruncateID(testContainer.ID)) {

+	if _, _, err := daemon.Create(&runconfig.Config{Image: GetTestImage(daemon).ID, Cmd: []string{"ls", "-al"}}, &runconfig.HostConfig{}, testContainer.Name); err == nil || !strings.Contains(err.Error(), common.TruncateID(testContainer.ID)) {

 		t.Fatalf("Name conflict error doesn't include the correct short id. Message was: %s", err.Error())

 	}

new file mode 100644

@@ -0,0 +1,38 @@

+package common

+

+import (

+	"crypto/rand"

+	"encoding/hex"

+	"io"

+	"strconv"

+)

+

+// TruncateID returns a shorthand version of a string identifier for convenience.

+// A collision with other shorthands is very unlikely, but possible.

+// In case of a collision a lookup with TruncIndex.Get() will fail, and the caller

+// will need to use a langer prefix, or the full-length Id.

+func TruncateID(id string) string {

+	shortLen := 12

+	if len(id) < shortLen {

+		shortLen = len(id)

+	}

+	return id[:shortLen]

+}

+

+// GenerateRandomID returns an unique id

+func GenerateRandomID() string {

+	for {

+		id := make([]byte, 32)

+		if _, err := io.ReadFull(rand.Reader, id); err != nil {

+			panic(err) // This shouldn't happen

+		}

+		value := hex.EncodeToString(id)

+		// if we try to parse the truncated for as an int and we don't have

+		// an error then the value is all numberic and causes issues when

+		// used as a hostname. ref #3869

+		if _, err := strconv.ParseInt(TruncateID(value), 10, 64); err == nil {

+			continue

+		}

+		return value

+	}

+}

@@ -4,7 +4,7 @@ import (

 	"math/rand"

 	"testing"

-	"github.com/docker/docker/utils"

+	"github.com/docker/docker/pkg/common"

 )

 // Test the behavior of TruncIndex, an index for querying IDs from a non-conflicting prefix.

@@ -111,7 +111,7 @@ func assertIndexGet(t *testing.T, index *TruncIndex, input, expectedResult strin

 func BenchmarkTruncIndexAdd100(b *testing.B) {

 	var testSet []string

 	for i := 0; i < 100; i++ {

-		testSet = append(testSet, utils.GenerateRandomID())

+		testSet = append(testSet, common.GenerateRandomID())

 	}

 	b.ResetTimer()

 	for i := 0; i < b.N; i++ {

@@ -127,7 +127,7 @@ func BenchmarkTruncIndexAdd100(b *testing.B) {

 func BenchmarkTruncIndexAdd250(b *testing.B) {

 	var testSet []string

 	for i := 0; i < 250; i++ {

-		testSet = append(testSet, utils.GenerateRandomID())

+		testSet = append(testSet, common.GenerateRandomID())

 	}

 	b.ResetTimer()

 	for i := 0; i < b.N; i++ {

@@ -143,7 +143,7 @@ func BenchmarkTruncIndexAdd250(b *testing.B) {

 func BenchmarkTruncIndexAdd500(b *testing.B) {

 	var testSet []string

 	for i := 0; i < 500; i++ {

-		testSet = append(testSet, utils.GenerateRandomID())

+		testSet = append(testSet, common.GenerateRandomID())

 	}

 	b.ResetTimer()

 	for i := 0; i < b.N; i++ {

@@ -160,7 +160,7 @@ func BenchmarkTruncIndexGet100(b *testing.B) {

 	var testSet []string

 	var testKeys []string

 	for i := 0; i < 100; i++ {

-		testSet = append(testSet, utils.GenerateRandomID())

+		testSet = append(testSet, common.GenerateRandomID())

 	}

 	index := NewTruncIndex([]string{})

 	for _, id := range testSet {

@@ -184,7 +184,7 @@ func BenchmarkTruncIndexGet250(b *testing.B) {

 	var testSet []string

 	var testKeys []string

 	for i := 0; i < 250; i++ {

-		testSet = append(testSet, utils.GenerateRandomID())

+		testSet = append(testSet, common.GenerateRandomID())

 	}

 	index := NewTruncIndex([]string{})

 	for _, id := range testSet {

@@ -208,7 +208,7 @@ func BenchmarkTruncIndexGet500(b *testing.B) {

 	var testSet []string

 	var testKeys []string

 	for i := 0; i < 500; i++ {

-		testSet = append(testSet, utils.GenerateRandomID())

+		testSet = append(testSet, common.GenerateRandomID())

 	}

 	index := NewTruncIndex([]string{})

 	for _, id := range testSet {

@@ -231,7 +231,7 @@ func BenchmarkTruncIndexGet500(b *testing.B) {

 func BenchmarkTruncIndexDelete100(b *testing.B) {

 	var testSet []string

 	for i := 0; i < 100; i++ {

-		testSet = append(testSet, utils.GenerateRandomID())

+		testSet = append(testSet, common.GenerateRandomID())

 	}

 	b.ResetTimer()

 	for i := 0; i < b.N; i++ {

@@ -254,7 +254,7 @@ func BenchmarkTruncIndexDelete100(b *testing.B) {

 func BenchmarkTruncIndexDelete250(b *testing.B) {

 	var testSet []string

 	for i := 0; i < 250; i++ {

-		testSet = append(testSet, utils.GenerateRandomID())

+		testSet = append(testSet, common.GenerateRandomID())

 	}

 	b.ResetTimer()

 	for i := 0; i < b.N; i++ {

@@ -277,7 +277,7 @@ func BenchmarkTruncIndexDelete250(b *testing.B) {

 func BenchmarkTruncIndexDelete500(b *testing.B) {

 	var testSet []string

 	for i := 0; i < 500; i++ {

-		testSet = append(testSet, utils.GenerateRandomID())

+		testSet = append(testSet, common.GenerateRandomID())

 	}

 	b.ResetTimer()

 	for i := 0; i < b.N; i++ {

@@ -300,7 +300,7 @@ func BenchmarkTruncIndexDelete500(b *testing.B) {

 func BenchmarkTruncIndexNew100(b *testing.B) {

 	var testSet []string

 	for i := 0; i < 100; i++ {

-		testSet = append(testSet, utils.GenerateRandomID())

+		testSet = append(testSet, common.GenerateRandomID())

 	}

 	b.ResetTimer()

 	for i := 0; i < b.N; i++ {

@@ -311,7 +311,7 @@ func BenchmarkTruncIndexNew100(b *testing.B) {

 func BenchmarkTruncIndexNew250(b *testing.B) {

 	var testSet []string

 	for i := 0; i < 250; i++ {

-		testSet = append(testSet, utils.GenerateRandomID())

+		testSet = append(testSet, common.GenerateRandomID())

 	}

 	b.ResetTimer()

 	for i := 0; i < b.N; i++ {

@@ -322,7 +322,7 @@ func BenchmarkTruncIndexNew250(b *testing.B) {

 func BenchmarkTruncIndexNew500(b *testing.B) {

 	var testSet []string

 	for i := 0; i < 500; i++ {

-		testSet = append(testSet, utils.GenerateRandomID())

+		testSet = append(testSet, common.GenerateRandomID())

 	}

 	b.ResetTimer()