Refactor pkg/common, Fixes #11599

Signed-off-by: Antonio Murdaca <me@runcom.ninja>

api/client/commands.go

@@ -33,7 +33,6 @@ 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"
@@ -43,6 +42,7 @@ import (
 	"github.com/docker/docker/pkg/promise"
 	"github.com/docker/docker/pkg/resolvconf"
 	"github.com/docker/docker/pkg/signal"
+	"github.com/docker/docker/pkg/stringid"
 	"github.com/docker/docker/pkg/symlink"
 	"github.com/docker/docker/pkg/term"
 	"github.com/docker/docker/pkg/timeutils"
@@ -1165,7 +1165,7 @@ func (cli *DockerCli) CmdHistory(args ...string) error {
 			if *noTrunc {
 				fmt.Fprintf(w, "%s\t", outID)
 			} else {
-				fmt.Fprintf(w, "%s\t", common.TruncateID(outID))
+				fmt.Fprintf(w, "%s\t", stringid.TruncateID(outID))
 			}
 
 			fmt.Fprintf(w, "%s ago\t", units.HumanDuration(time.Now().UTC().Sub(time.Unix(out.GetInt64("Created"), 0))))
@@ -1180,7 +1180,7 @@ func (cli *DockerCli) CmdHistory(args ...string) error {
 			if *noTrunc {
 				fmt.Fprintln(w, outID)
 			} else {
-				fmt.Fprintln(w, common.TruncateID(outID))
+				fmt.Fprintln(w, stringid.TruncateID(outID))
 			}
 		}
 	}
@@ -1479,7 +1479,7 @@ func (cli *DockerCli) CmdImages(args ...string) error {
 			}
 
 			if matchName != "" {
-				if matchName == image.Get("Id") || matchName == common.TruncateID(image.Get("Id")) {
+				if matchName == image.Get("Id") || matchName == stringid.TruncateID(image.Get("Id")) {
 					startImage = image
 				}
 
@@ -1549,7 +1549,7 @@ func (cli *DockerCli) CmdImages(args ...string) error {
 		for _, out := range outs.Data {
 			outID := out.Get("Id")
 			if !*noTrunc {
-				outID = common.TruncateID(outID)
+				outID = stringid.TruncateID(outID)
 			}
 
 			repoTags := out.GetList("RepoTags")
@@ -1629,8 +1629,8 @@ func (cli *DockerCli) printVizNode(noTrunc bool, image *engine.Env, prefix strin
 		imageID = image.Get("Id")
 		parentID = image.Get("ParentId")
 	} else {
-		imageID = common.TruncateID(image.Get("Id"))
+		imageID = stringid.TruncateID(image.Get("Id"))
-		parentID = common.TruncateID(image.Get("ParentId"))
+		parentID = stringid.TruncateID(image.Get("ParentId"))
 	}
 	if parentID == "" {
 		fmt.Fprintf(cli.out, " base -> \"%s\" [style=invis]\n", imageID)
@@ -1649,7 +1649,7 @@ func (cli *DockerCli) printTreeNode(noTrunc bool, image *engine.Env, prefix stri
 	if noTrunc {
 		imageID = image.Get("Id")
 	} else {
-		imageID = common.TruncateID(image.Get("Id"))
+		imageID = stringid.TruncateID(image.Get("Id"))
 	}
 
 	fmt.Fprintf(cli.out, "%s%s Virtual Size: %s", prefix, imageID, units.HumanSize(float64(image.GetInt64("VirtualSize"))))
@@ -1757,7 +1757,7 @@ func (cli *DockerCli) CmdPs(args ...string) error {
 		outID := out.Get("Id")
 
 		if !*noTrunc {
-			outID = common.TruncateID(outID)
+			outID = stringid.TruncateID(outID)
 		}
 
 		if *quiet {

builder/evaluator.go

@@ -32,8 +32,8 @@ 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/stringid"
 	"github.com/docker/docker/pkg/symlink"
 	"github.com/docker/docker/pkg/tarsum"
 	"github.com/docker/docker/registry"
@@ -177,7 +177,7 @@ func (b *Builder) Run(context io.Reader) (string, error) {
 			}
 			return "", err
 		}
-		fmt.Fprintf(b.OutStream, " ---> %s\n", common.TruncateID(b.image))
+		fmt.Fprintf(b.OutStream, " ---> %s\n", stringid.TruncateID(b.image))
 		if b.Remove {
 			b.clearTmp()
 		}
@@ -187,7 +187,7 @@ 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", common.TruncateID(b.image))
+	fmt.Fprintf(b.OutStream, "Successfully built %s\n", stringid.TruncateID(b.image))
 	return b.image, nil
 }
 

builder/internals.go

@@ -25,10 +25,10 @@ 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/progressreader"
+	"github.com/docker/docker/pkg/stringid"
 	"github.com/docker/docker/pkg/symlink"
 	"github.com/docker/docker/pkg/system"
 	"github.com/docker/docker/pkg/tarsum"
@@ -557,7 +557,7 @@ func (b *Builder) create() (*daemon.Container, error) {
 	}
 
 	b.TmpContainers[c.ID] = struct{}{}
-	fmt.Fprintf(b.OutStream, " ---> Running in %s\n", common.TruncateID(c.ID))
+	fmt.Fprintf(b.OutStream, " ---> Running in %s\n", stringid.TruncateID(c.ID))
 
 	if len(config.Cmd) > 0 {
 		// override the entry point that may have been picked up from the base image
@@ -753,11 +753,11 @@ func (b *Builder) clearTmp() {
 		}
 
 		if err := b.Daemon.Rm(tmp); err != nil {
-			fmt.Fprintf(b.OutStream, "Error removing intermediate container %s: %v\n", common.TruncateID(c), err)
+			fmt.Fprintf(b.OutStream, "Error removing intermediate container %s: %v\n", stringid.TruncateID(c), err)
 			return
 		}
 		b.Daemon.DeleteVolumes(tmp.VolumePaths())
 		delete(b.TmpContainers, c)
-		fmt.Fprintf(b.OutStream, "Removing intermediate container %s\n", common.TruncateID(c))
+		fmt.Fprintf(b.OutStream, "Removing intermediate container %s\n", stringid.TruncateID(c))
 	}
 }

daemon/container.go

@@ -30,12 +30,12 @@ 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/directory"
 	"github.com/docker/docker/pkg/etchosts"
 	"github.com/docker/docker/pkg/ioutils"
 	"github.com/docker/docker/pkg/promise"
 	"github.com/docker/docker/pkg/resolvconf"
+	"github.com/docker/docker/pkg/stringid"
 	"github.com/docker/docker/pkg/symlink"
 	"github.com/docker/docker/pkg/ulimit"
 	"github.com/docker/docker/runconfig"
@@ -739,7 +739,7 @@ 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", common.TruncateID(container.ID))
+			log.Infof("Container %s failed to exit within 10 seconds of kill - trying direct SIGKILL", stringid.TruncateID(container.ID))
 			if err := syscall.Kill(pid, 9); err != nil {
 				if err != syscall.ESRCH {
 					return err

daemon/daemon.go

@@ -31,13 +31,13 @@ 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"
 	"github.com/docker/docker/pkg/parsers"
 	"github.com/docker/docker/pkg/parsers/kernel"
 	"github.com/docker/docker/pkg/resolvconf"
+	"github.com/docker/docker/pkg/stringid"
 	"github.com/docker/docker/pkg/sysinfo"
 	"github.com/docker/docker/pkg/truncindex"
 	"github.com/docker/docker/runconfig"
@@ -517,7 +517,7 @@ func (daemon *Daemon) mergeAndVerifyConfig(config *runconfig.Config, img *image.
 func (daemon *Daemon) generateIdAndName(name string) (string, string, error) {
 	var (
 		err error
-		id  = common.GenerateRandomID()
+		id  = stringid.GenerateRandomID()
 	)
 
 	if name == "" {
@@ -562,7 +562,7 @@ 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,
-				common.TruncateID(conflictingContainer.ID))
+				stringid.TruncateID(conflictingContainer.ID))
 		}
 	}
 	return name, nil
@@ -585,7 +585,7 @@ func (daemon *Daemon) generateNewName(id string) (string, error) {
 		return name, nil
 	}
 
-	name = "/" + common.TruncateID(id)
+	name = "/" + stringid.TruncateID(id)
 	if _, err := daemon.containerGraph.Set(name, id); err != nil {
 		return "", err
 	}

daemon/exec.go

@@ -12,9 +12,9 @@ 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/pkg/stringid"
 	"github.com/docker/docker/runconfig"
 )
 
@@ -141,7 +141,7 @@ func (d *Daemon) ContainerExecCreate(job *engine.Job) engine.Status {
 	}
 
 	execConfig := &execConfig{
-		ID:            common.GenerateRandomID(),
+		ID:            stringid.GenerateRandomID(),
 		OpenStdin:     config.AttachStdin,
 		OpenStdout:    config.AttachStdout,
 		OpenStderr:    config.AttachStderr,

daemon/graphdriver/aufs/aufs.go

@@ -34,9 +34,9 @@ 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"
 	"github.com/docker/docker/pkg/directory"
 	mountpk "github.com/docker/docker/pkg/mount"
+	"github.com/docker/docker/pkg/stringid"
 	"github.com/docker/libcontainer/label"
 )
 
@@ -405,7 +405,7 @@ func (a *Driver) Cleanup() error {
 
 	for _, id := range ids {
 		if err := a.unmount(id); err != nil {
-			log.Errorf("Unmounting %s: %s", common.TruncateID(id), err)
+			log.Errorf("Unmounting %s: %s", stringid.TruncateID(id), err)
 		}
 	}
 

daemon/image_delete.go

@@ -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/pkg/stringid"
 	"github.com/docker/docker/utils"
 )
 
@@ -148,11 +148,11 @@ 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", common.TruncateID(imgID), common.TruncateID(container.ID))
+						return fmt.Errorf("Conflict, cannot force delete %s because the running container %s is using it, stop it and retry", stringid.TruncateID(imgID), stringid.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))
+					return fmt.Errorf("Conflict, cannot delete %s because the running container %s is using it, stop it and use -f to force", stringid.TruncateID(imgID), stringid.TruncateID(container.ID))
 				} else if !force {
-					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 fmt.Errorf("Conflict, cannot delete %s because the container %s is using it, use -f to force", stringid.TruncateID(imgID), stringid.TruncateID(container.ID))
 				}
 			}
 			return nil

daemon/monitor.go

@@ -8,7 +8,7 @@ import (
 
 	log "github.com/Sirupsen/logrus"
 	"github.com/docker/docker/daemon/execdriver"
-	"github.com/docker/docker/pkg/common"
+	"github.com/docker/docker/pkg/stringid"
 	"github.com/docker/docker/runconfig"
 )
 
@@ -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",
-				common.TruncateID(m.container.ID), max)
+				stringid.TruncateID(m.container.ID), max)
 			return false
 		}
 

engine/engine.go

@@ -10,8 +10,8 @@ import (
 	"sync"
 	"time"
 
-	"github.com/docker/docker/pkg/common"
 	"github.com/docker/docker/pkg/ioutils"
+	"github.com/docker/docker/pkg/stringutils"
 )
 
 // Installer is a standard interface for objects which can "install" themselves
@@ -78,7 +78,7 @@ func (eng *Engine) RegisterCatchall(catchall Handler) {
 func New() *Engine {
 	eng := &Engine{
 		handlers: make(map[string]Handler),
-		id:       common.RandomString(),
+		id:       stringutils.GenerateRandomString(),
 		Stdout:   os.Stdout,
 		Stderr:   os.Stderr,
 		Stdin:    os.Stdin,

engine/env_test.go

@@ -3,24 +3,12 @@ package engine
 import (
 	"bytes"
 	"encoding/json"
-	"math/rand"
 	"testing"
 	"time"
+
+	"github.com/docker/docker/pkg/stringutils"
 )
 
-const chars = "abcdefghijklmnopqrstuvwxyz" +
-	"ABCDEFGHIJKLMNOPQRSTUVWXYZ" +
-	"~!@#$%^&*()-_+={}[]\\|<,>.?/\"';:` "
-
-// RandomString returns random string of specified length
-func RandomString(length int) string {
-	res := make([]byte, length)
-	for i := 0; i < length; i++ {
-		res[i] = chars[rand.Intn(len(chars))]
-	}
-	return string(res)
-}
-
 func TestEnvLenZero(t *testing.T) {
 	env := &Env{}
 	if env.Len() != 0 {
@@ -197,7 +185,7 @@ func TestMultiMap(t *testing.T) {
 func testMap(l int) [][2]string {
 	res := make([][2]string, l)
 	for i := 0; i < l; i++ {
-		t := [2]string{RandomString(5), RandomString(20)}
+		t := [2]string{stringutils.GenerateRandomAsciiString(5), stringutils.GenerateRandomAsciiString(20)}
 		res[i] = t
 	}
 	return res

graph/graph.go

@@ -17,8 +17,8 @@ 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/progressreader"
+	"github.com/docker/docker/pkg/stringid"
 	"github.com/docker/docker/pkg/truncindex"
 	"github.com/docker/docker/runconfig"
 	"github.com/docker/docker/utils"
@@ -118,7 +118,7 @@ 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:            common.GenerateRandomID(),
+		ID:            stringid.GenerateRandomID(),
 		Comment:       comment,
 		Created:       time.Now().UTC(),
 		DockerVersion: dockerversion.VERSION,
@@ -217,7 +217,7 @@ func (graph *Graph) TempLayerArchive(id string, sf *utils.StreamFormatter, outpu
 		Formatter: sf,
 		Size:      0,
 		NewLines:  false,
-		ID:        common.TruncateID(id),
+		ID:        stringid.TruncateID(id),
 		Action:    "Buffering to disk",
 	})
 	defer progressReader.Close()
@@ -226,7 +226,7 @@ func (graph *Graph) TempLayerArchive(id string, sf *utils.StreamFormatter, outpu
 
 // 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", common.GenerateRandomID())
+	dir := path.Join(graph.Root, "_tmp", stringid.GenerateRandomID())
 	if err := os.MkdirAll(dir, 0700); err != nil {
 		return "", err
 	}

graph/pull.go

@@ -14,8 +14,8 @@ import (
 	"github.com/docker/distribution/digest"
 	"github.com/docker/docker/engine"
 	"github.com/docker/docker/image"
-	"github.com/docker/docker/pkg/common"
 	"github.com/docker/docker/pkg/progressreader"
+	"github.com/docker/docker/pkg/stringid"
 	"github.com/docker/docker/registry"
 	"github.com/docker/docker/utils"
 )
@@ -172,9 +172,9 @@ 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(common.TruncateID(img.ID), "Layer already being pulled by another client. Waiting.", nil))
+					out.Write(sf.FormatProgress(stringid.TruncateID(img.ID), "Layer already being pulled by another client. Waiting.", nil))
 					<-c
-					out.Write(sf.FormatProgress(common.TruncateID(img.ID), "Download complete", nil))
+					out.Write(sf.FormatProgress(stringid.TruncateID(img.ID), "Download complete", nil))
 				} else {
 					log.Debugf("Image (id: %s) pull is already running, skipping: %v", img.ID, err)
 				}
@@ -185,12 +185,12 @@ func (s *TagStore) pullRepository(r *registry.Session, out io.Writer, repoInfo *
 			}
 			defer s.poolRemove("pull", "img:"+img.ID)
 
-			out.Write(sf.FormatProgress(common.TruncateID(img.ID), fmt.Sprintf("Pulling image (%s) from %s", img.Tag, repoInfo.CanonicalName), nil))
+			out.Write(sf.FormatProgress(stringid.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(common.TruncateID(img.ID), fmt.Sprintf("Pulling image (%s) from %s, mirror: %s", img.Tag, repoInfo.CanonicalName, ep), nil))
+				out.Write(sf.FormatProgress(stringid.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)
@@ -202,12 +202,12 @@ func (s *TagStore) pullRepository(r *registry.Session, out io.Writer, repoInfo *
 			}
 			if !success {
 				for _, ep := range repoData.Endpoints {
-					out.Write(sf.FormatProgress(common.TruncateID(img.ID), fmt.Sprintf("Pulling image (%s) from %s, endpoint: %s", img.Tag, repoInfo.CanonicalName, ep), nil))
+					out.Write(sf.FormatProgress(stringid.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(common.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(stringid.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
@@ -217,13 +217,13 @@ 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(common.TruncateID(img.ID), err.Error(), nil))
+				out.Write(sf.FormatProgress(stringid.TruncateID(img.ID), err.Error(), nil))
 				if parallel {
 					errors <- err
 					return
 				}
 			}
-			out.Write(sf.FormatProgress(common.TruncateID(img.ID), "Download complete", nil))
+			out.Write(sf.FormatProgress(stringid.TruncateID(img.ID), "Download complete", nil))
 
 			if parallel {
 				errors <- nil
@@ -270,7 +270,7 @@ func (s *TagStore) pullImage(r *registry.Session, out io.Writer, imgID, endpoint
 	if err != nil {
 		return false, err
 	}
-	out.Write(sf.FormatProgress(common.TruncateID(imgID), "Pulling dependent layers", nil))
+	out.Write(sf.FormatProgress(stringid.TruncateID(imgID), "Pulling dependent layers", nil))
 	// FIXME: Try to stream the images?
 	// FIXME: Launch the getRemoteImage() in goroutines
 
@@ -286,7 +286,7 @@ 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(common.TruncateID(id), "Pulling metadata", nil))
+			out.Write(sf.FormatProgress(stringid.TruncateID(id), "Pulling metadata", nil))
 			var (
 				imgJSON []byte
 				imgSize int
@@ -297,7 +297,7 @@ 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(common.TruncateID(id), "Error pulling dependent layers", nil))
+					out.Write(sf.FormatProgress(stringid.TruncateID(id), "Error pulling dependent layers", nil))
 					return layers_downloaded, err
 				} else if err != nil {
 					time.Sleep(time.Duration(j) * 500 * time.Millisecond)
@@ -306,7 +306,7 @@ 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(common.TruncateID(id), "Error pulling dependent layers", nil))
+					out.Write(sf.FormatProgress(stringid.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)
@@ -322,7 +322,7 @@ 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(common.TruncateID(id), status, nil))
+				out.Write(sf.FormatProgress(stringid.TruncateID(id), status, nil))
 				layer, err := r.GetRemoteImageLayer(img.ID, endpoint, token, int64(imgSize))
 				if uerr, ok := err.(*url.Error); ok {
 					err = uerr.Err
@@ -331,7 +331,7 @@ 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(common.TruncateID(id), "Error pulling dependent layers", nil))
+					out.Write(sf.FormatProgress(stringid.TruncateID(id), "Error pulling dependent layers", nil))
 					return layers_downloaded, err
 				}
 				layers_downloaded = true
@@ -344,21 +344,21 @@ func (s *TagStore) pullImage(r *registry.Session, out io.Writer, imgID, endpoint
 						Formatter: sf,
 						Size:      imgSize,
 						NewLines:  false,
-						ID:        common.TruncateID(id),
+						ID:        stringid.TruncateID(id),
 						Action:    "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(common.TruncateID(id), "Error downloading dependent layers", nil))
+					out.Write(sf.FormatProgress(stringid.TruncateID(id), "Error downloading dependent layers", nil))
 					return layers_downloaded, err
 				} else {
 					break
 				}
 			}
 		}
-		out.Write(sf.FormatProgress(common.TruncateID(id), "Download complete", nil))
+		out.Write(sf.FormatProgress(stringid.TruncateID(id), "Download complete", nil))
 	}
 	return layers_downloaded, nil
 }
@@ -478,16 +478,16 @@ func (s *TagStore) pullV2Tag(eng *engine.Engine, r *registry.Session, out io.Wri
 		}
 		downloads[i].digest = dgst
 
-		out.Write(sf.FormatProgress(common.TruncateID(img.ID), "Pulling fs layer", nil))
+		out.Write(sf.FormatProgress(stringid.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(common.TruncateID(img.ID), "Layer already being pulled by another client. Waiting.", nil))
+					out.Write(sf.FormatProgress(stringid.TruncateID(img.ID), "Layer already being pulled by another client. Waiting.", nil))
 					<-c
-					out.Write(sf.FormatProgress(common.TruncateID(img.ID), "Download complete", nil))
+					out.Write(sf.FormatProgress(stringid.TruncateID(img.ID), "Download complete", nil))
 				} else {
 					log.Debugf("Image (id: %s) pull is already running, skipping: %v", img.ID, err)
 				}
@@ -515,20 +515,20 @@ func (s *TagStore) pullV2Tag(eng *engine.Engine, r *registry.Session, out io.Wri
 					Formatter: sf,
 					Size:      int(l),
 					NewLines:  false,
-					ID:        common.TruncateID(img.ID),
+					ID:        stringid.TruncateID(img.ID),
 					Action:    "Downloading",
 				})); err != nil {
 					return fmt.Errorf("unable to copy v2 image blob data: %s", err)
 				}
 
-				out.Write(sf.FormatProgress(common.TruncateID(img.ID), "Verifying Checksum", nil))
+				out.Write(sf.FormatProgress(stringid.TruncateID(img.ID), "Verifying Checksum", nil))
 
 				if !verifier.Verified() {
 					log.Infof("Image verification failed: checksum mismatch for %q", di.digest.String())
 					verified = false
 				}
 
-				out.Write(sf.FormatProgress(common.TruncateID(img.ID), "Download complete", nil))
+				out.Write(sf.FormatProgress(stringid.TruncateID(img.ID), "Download complete", nil))
 
 				log.Debugf("Downloaded %s to tempfile %s", img.ID, tmpFile.Name())
 				di.tmpFile = tmpFile
@@ -574,7 +574,7 @@ func (s *TagStore) pullV2Tag(eng *engine.Engine, r *registry.Session, out io.Wri
 						Out:       out,
 						Formatter: sf,
 						Size:      int(d.length),
-						ID:        common.TruncateID(d.img.ID),
+						ID:        stringid.TruncateID(d.img.ID),
 						Action:    "Extracting",
 					}))
 				if err != nil {
@@ -583,10 +583,10 @@ func (s *TagStore) pullV2Tag(eng *engine.Engine, r *registry.Session, out io.Wri
 
 				// FIXME: Pool release here for parallel tag pull (ensures any downloads block until fully extracted)
 			}
-			out.Write(sf.FormatProgress(common.TruncateID(d.img.ID), "Pull complete", nil))
+			out.Write(sf.FormatProgress(stringid.TruncateID(d.img.ID), "Pull complete", nil))
 			tagUpdated = true
 		} else {
-			out.Write(sf.FormatProgress(common.TruncateID(d.img.ID), "Already exists", nil))
+			out.Write(sf.FormatProgress(stringid.TruncateID(d.img.ID), "Already exists", nil))
 		}
 
 	}

graph/push.go

@@ -16,8 +16,8 @@ import (
 	"github.com/docker/distribution/digest"
 	"github.com/docker/docker/engine"
 	"github.com/docker/docker/image"
-	"github.com/docker/docker/pkg/common"
 	"github.com/docker/docker/pkg/progressreader"
+	"github.com/docker/docker/pkg/stringid"
 	"github.com/docker/docker/registry"
 	"github.com/docker/docker/runconfig"
 	"github.com/docker/docker/utils"
@@ -139,7 +139,7 @@ func lookupImageOnEndpoint(wg *sync.WaitGroup, r *registry.Session, out io.Write
 			imagesToPush <- image.id
 			continue
 		}
-		out.Write(sf.FormatStatus("", "Image %s already pushed, skipping", common.TruncateID(image.id)))
+		out.Write(sf.FormatStatus("", "Image %s already pushed, skipping", stringid.TruncateID(image.id)))
 	}
 }
 
@@ -191,7 +191,7 @@ 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}", common.TruncateID(id), endpoint+"repositories/"+remoteName+"/tags/"+tag))
+			out.Write(sf.FormatStatus("", "Pushing tag for rev [%s] on {%s}", stringid.TruncateID(id), endpoint+"repositories/"+remoteName+"/tags/"+tag))
 			if err := r.PushRegistryTag(remoteName, id, tag, endpoint, repo.Tokens); err != nil {
 				return err
 			}
@@ -244,7 +244,7 @@ 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(common.TruncateID(imgID), "Pushing", nil))
+	out.Write(sf.FormatProgress(stringid.TruncateID(imgID), "Pushing", nil))
 
 	imgData := &registry.ImgData{
 		ID: imgID,
@@ -253,7 +253,7 @@ 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(common.TruncateID(imgData.ID), "Image already pushed, skipping", nil))
+			out.Write(sf.FormatProgress(stringid.TruncateID(imgData.ID), "Image already pushed, skipping", nil))
 			return "", nil
 		}
 		return "", err
@@ -275,7 +275,7 @@ func (s *TagStore) pushImage(r *registry.Session, out io.Writer, imgID, ep strin
 			Formatter: sf,
 			Size:      int(layerData.Size),
 			NewLines:  false,
-			ID:        common.TruncateID(imgData.ID),
+			ID:        stringid.TruncateID(imgData.ID),
 			Action:    "Pushing",
 		}), ep, token, jsonRaw)
 	if err != nil {
@@ -288,7 +288,7 @@ func (s *TagStore) pushImage(r *registry.Session, out io.Writer, imgID, ep strin
 		return "", err
 	}
 
-	out.Write(sf.FormatProgress(common.TruncateID(imgData.ID), "Image successfully pushed", nil))
+	out.Write(sf.FormatProgress(stringid.TruncateID(imgData.ID), "Image successfully pushed", nil))
 	return imgData.Checksum, nil
 }
 
@@ -385,7 +385,7 @@ func (s *TagStore) pushV2Repository(r *registry.Session, localRepo Repository, o
 				// Call mount blob
 				exists, err = r.HeadV2ImageBlob(endpoint, repoInfo.RemoteName, sumParts[0], sumParts[1], auth)
 				if err != nil {
-					out.Write(sf.FormatProgress(common.TruncateID(layer.ID), "Image push failed", nil))
+					out.Write(sf.FormatProgress(stringid.TruncateID(layer.ID), "Image push failed", nil))
 					return err
 				}
 			}
@@ -400,7 +400,7 @@ func (s *TagStore) pushV2Repository(r *registry.Session, localRepo Repository, o
 					checksum = cs
 				}
 			} else {
-				out.Write(sf.FormatProgress(common.TruncateID(layer.ID), "Image already exists", nil))
+				out.Write(sf.FormatProgress(stringid.TruncateID(layer.ID), "Image already exists", nil))
 			}
 			m.FSLayers[i] = &registry.FSLayer{BlobSum: checksum}
 			m.History[i] = &registry.ManifestHistory{V1Compatibility: string(jsonData)}
@@ -443,7 +443,7 @@ func (s *TagStore) pushV2Repository(r *registry.Session, localRepo Repository, o
 
 // 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 string, sf *utils.StreamFormatter, out io.Writer, auth *registry.RequestAuthorization) (string, error) {
-	out.Write(sf.FormatProgress(common.TruncateID(img.ID), "Buffering to Disk", nil))
+	out.Write(sf.FormatProgress(stringid.TruncateID(img.ID), "Buffering to Disk", nil))
 
 	image, err := s.graph.Get(img.ID)
 	if err != nil {
@@ -481,13 +481,13 @@ func (s *TagStore) pushV2Image(r *registry.Session, img *image.Image, endpoint *
 			Formatter: sf,
 			Size:      int(size),
 			NewLines:  false,
-			ID:        common.TruncateID(img.ID),
+			ID:        stringid.TruncateID(img.ID),
 			Action:    "Pushing",
 		}), auth); err != nil {
-		out.Write(sf.FormatProgress(common.TruncateID(img.ID), "Image push failed", nil))
+		out.Write(sf.FormatProgress(stringid.TruncateID(img.ID), "Image push failed", nil))
 		return "", err
 	}
-	out.Write(sf.FormatProgress(common.TruncateID(img.ID), "Image successfully pushed", nil))
+	out.Write(sf.FormatProgress(stringid.TruncateID(img.ID), "Image successfully pushed", nil))
 	return dgst.String(), nil
 }
 

graph/tags.go

@@ -13,8 +13,8 @@ import (
 	"sync"
 
 	"github.com/docker/docker/image"
-	"github.com/docker/docker/pkg/common"
 	"github.com/docker/docker/pkg/parsers"
+	"github.com/docker/docker/pkg/stringid"
 	"github.com/docker/docker/registry"
 	"github.com/docker/docker/utils"
 	"github.com/docker/libtrust"
@@ -163,7 +163,7 @@ func (store *TagStore) ImageName(id string) string {
 	if names, exists := store.ByID()[id]; exists && len(names) > 0 {
 		return names[0]
 	}
-	return common.TruncateID(id)
+	return stringid.TruncateID(id)
 }
 
 func (store *TagStore) DeleteAll(id string) error {
@@ -331,7 +331,7 @@ func (store *TagStore) GetRepoRefs() map[string][]string {
 
 	for name, repository := range store.Repositories {
 		for tag, id := range repository {
-			shortID := common.TruncateID(id)
+			shortID := stringid.TruncateID(id)
 			reporefs[shortID] = append(reporefs[shortID], utils.ImageReference(name, tag))
 		}
 	}

integration-cli/docker_cli_build_test.go

@@ -22,6 +22,7 @@ import (
 
 	"github.com/docker/docker/builder/command"
 	"github.com/docker/docker/pkg/archive"
+	"github.com/docker/docker/pkg/stringutils"
 )
 
 func TestBuildJSONEmptyRun(t *testing.T) {
@@ -4420,7 +4421,7 @@ func TestBuildOnBuildOutput(t *testing.T) {
 }
 
 func TestBuildInvalidTag(t *testing.T) {
-	name := "abcd:" + makeRandomString(200)
+	name := "abcd:" + stringutils.GenerateRandomAlphaOnlyString(200)
 	defer deleteImages(name)
 	_, out, err := buildImageWithOut(name, "FROM scratch\nMAINTAINER quux\n", true)
 	// if the error doesnt check for illegal tag name, or the image is built

integration-cli/docker_cli_images_test.go

@@ -9,7 +9,7 @@ import (
 	"testing"
 	"time"
 
-	"github.com/docker/docker/pkg/common"
+	"github.com/docker/docker/pkg/stringid"
 )
 
 func TestImagesEnsureImageIsListed(t *testing.T) {
@@ -196,7 +196,7 @@ func TestImagesEnsureDanglingImageOnlyListedOnce(t *testing.T) {
 	if err != nil {
 		t.Fatalf("error tagging foobox: %s", err)
 	}
-	imageId := common.TruncateID(strings.TrimSpace(out))
+	imageId := stringid.TruncateID(strings.TrimSpace(out))
 	defer deleteImages(imageId)
 
 	// overwrite the tag, making the previous image dangling

integration-cli/docker_cli_tag_test.go

@@ -5,6 +5,8 @@ import (
 	"os/exec"
 	"strings"
 	"testing"
+
+	"github.com/docker/docker/pkg/stringutils"
 )
 
 // tagging a named image in a new unprefixed repo should work
@@ -59,7 +61,7 @@ func TestTagInvalidUnprefixedRepo(t *testing.T) {
 
 // ensure we don't allow the use of invalid tags; these tag operations should fail
 func TestTagInvalidPrefixedRepo(t *testing.T) {
-	long_tag := makeRandomString(121)
+	long_tag := stringutils.GenerateRandomAlphaOnlyString(121)
 
 	invalidTags := []string{"repo:fo$z$", "repo:Foo@3cc", "repo:Foo$3", "repo:Foo*3", "repo:Fo^3", "repo:Foo!3", "repo:%goodbye", "repo:#hashtagit", "repo:F)xcz(", "repo:-foo", "repo:..", long_tag}
 

integration-cli/docker_utils.go

@@ -22,6 +22,7 @@ import (
 	"time"
 
 	"github.com/docker/docker/api"
+	"github.com/docker/docker/pkg/stringutils"
 )
 
 // Daemon represents a Docker daemon for the testing framework.
@@ -695,8 +696,8 @@ func (f *remoteFileServer) Close() error {
 
 func newRemoteFileServer(ctx *FakeContext) (*remoteFileServer, error) {
 	var (
-		image     = fmt.Sprintf("fileserver-img-%s", strings.ToLower(makeRandomString(10)))
+		image     = fmt.Sprintf("fileserver-img-%s", strings.ToLower(stringutils.GenerateRandomAlphaOnlyString(10)))
-		container = fmt.Sprintf("fileserver-cnt-%s", strings.ToLower(makeRandomString(10)))
+		container = fmt.Sprintf("fileserver-cnt-%s", strings.ToLower(stringutils.GenerateRandomAlphaOnlyString(10)))
 	)
 
 	// Build the image

integration-cli/utils.go

@@ -6,7 +6,6 @@ import (
 	"errors"
 	"fmt"
 	"io"
-	"math/rand"
 	"net/http"
 	"net/http/httptest"
 	"os"
@@ -17,6 +16,7 @@ import (
 	"syscall"
 	"time"
 
+	"github.com/docker/docker/pkg/stringutils"
 	"github.com/docker/docker/vendor/src/code.google.com/p/go/src/pkg/archive/tar"
 )
 
@@ -301,21 +301,10 @@ func copyWithCP(source, target string) error {
 	return nil
 }
 
-func makeRandomString(n int) string {
-	// make a really long string
-	letters := []byte("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ")
-	b := make([]byte, n)
-	r := rand.New(rand.NewSource(time.Now().UTC().UnixNano()))
-	for i := range b {
-		b[i] = letters[r.Intn(len(letters))]
-	}
-	return string(b)
-}
-
 // randomUnixTmpDirPath provides a temporary unix path with rand string appended.
 // does not create or checks if it exists.
 func randomUnixTmpDirPath(s string) string {
-	return path.Join("/tmp", fmt.Sprintf("%s.%s", s, makeRandomString(10)))
+	return path.Join("/tmp", fmt.Sprintf("%s.%s", s, stringutils.GenerateRandomAlphaOnlyString(10)))
 }
 
 // Reads chunkSize bytes from reader after every interval.

integration/commands_test.go

@@ -12,7 +12,7 @@ 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/stringid"
 	"github.com/docker/docker/pkg/term"
 	"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(common.TruncateID(container.ID)); err != nil {
+		if err := cli.CmdAttach(stringid.TruncateID(container.ID)); err != nil {
 			if err != io.ErrClosedPipe {
 				t.Fatal(err)
 			}

integration/graph_test.go

@@ -2,19 +2,20 @@ package docker
 
 import (
 	"errors"
-	"github.com/docker/docker/autogen/dockerversion"
-	"github.com/docker/docker/daemon/graphdriver"
-	"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"
 	"os"
 	"path"
 	"testing"
 	"time"
+
+	"github.com/docker/docker/autogen/dockerversion"
+	"github.com/docker/docker/daemon/graphdriver"
+	"github.com/docker/docker/graph"
+	"github.com/docker/docker/image"
+	"github.com/docker/docker/pkg/archive"
+	"github.com/docker/docker/pkg/stringid"
+	"github.com/docker/docker/utils"
 )
 
 func TestMount(t *testing.T) {
@@ -70,7 +71,7 @@ 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:      common.GenerateRandomID(),
+		ID:      stringid.GenerateRandomID(),
 		Comment: "testing",
 		Created: time.Now(),
 	}
@@ -130,7 +131,7 @@ func TestRegister(t *testing.T) {
 		t.Fatal(err)
 	}
 	image := &image.Image{
-		ID:      common.GenerateRandomID(),
+		ID:      stringid.GenerateRandomID(),
 		Comment: "testing",
 		Created: time.Now(),
 	}
@@ -160,7 +161,7 @@ func TestDeletePrefix(t *testing.T) {
 	graph, _ := tempGraph(t)
 	defer nukeGraph(graph)
 	img := createTestImage(graph, t)
-	if err := graph.Delete(common.TruncateID(img.ID)); err != nil {
+	if err := graph.Delete(stringid.TruncateID(img.ID)); err != nil {
 		t.Fatal(err)
 	}
 	assertNImages(graph, t, 0)
@@ -246,19 +247,19 @@ func TestByParent(t *testing.T) {
 	graph, _ := tempGraph(t)
 	defer nukeGraph(graph)
 	parentImage := &image.Image{
-		ID:      common.GenerateRandomID(),
+		ID:      stringid.GenerateRandomID(),
 		Comment: "parent",
 		Created: time.Now(),
 		Parent:  "",
 	}
 	childImage1 := &image.Image{
-		ID:      common.GenerateRandomID(),
+		ID:      stringid.GenerateRandomID(),
 		Comment: "child1",
 		Created: time.Now(),
 		Parent:  parentImage.ID,
 	}
 	childImage2 := &image.Image{
-		ID:      common.GenerateRandomID(),
+		ID:      stringid.GenerateRandomID(),
 		Comment: "child2",
 		Created: time.Now(),
 		Parent:  parentImage.ID,

integration/runtime_test.go

@@ -22,9 +22,9 @@ 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/pkg/stringid"
 	"github.com/docker/docker/runconfig"
 	"github.com/docker/docker/utils"
 )
@@ -306,7 +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(), common.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(), stringid.TruncateID(testContainer.ID)) {
 		t.Fatalf("Name conflict error doesn't include the correct short id. Message was: %v", err)
 	}
 

pkg/stringid/README.md

@@ -0,0 +1 @@
+This package provides helper functions for dealing with string identifiers

pkg/stringid/stringid.go

@@ -1,4 +1,4 @@
-package common
+package stringid
 
 import (
 	"crypto/rand"
@@ -36,12 +36,3 @@ func GenerateRandomID() string {
 		return value
 	}
 }
-
-func RandomString() string {
-	id := make([]byte, 32)
-
-	if _, err := io.ReadFull(rand.Reader, id); err != nil {
-		panic(err) // This shouldn't happen
-	}
-	return hex.EncodeToString(id)
-}

pkg/stringid/stringid_test.go

@@ -1,8 +1,14 @@
-package common
+package stringid
 
-import (
+import "testing"
-	"testing"
+
-)
+func TestGenerateRandomID(t *testing.T) {
+	id := GenerateRandomID()
+
+	if len(id) != 64 {
+		t.Fatalf("Id returned is incorrect: %s", id)
+	}
+}
 
 func TestShortenId(t *testing.T) {
 	id := GenerateRandomID()
@@ -27,33 +33,3 @@ func TestShortenIdInvalid(t *testing.T) {
 		t.Fatalf("Id returned is incorrect: truncate on %s returned %s", id, truncID)
 	}
 }
-
-func TestGenerateRandomID(t *testing.T) {
-	id := GenerateRandomID()
-
-	if len(id) != 64 {
-		t.Fatalf("Id returned is incorrect: %s", id)
-	}
-}
-
-func TestRandomString(t *testing.T) {
-	id := RandomString()
-	if len(id) != 64 {
-		t.Fatalf("Id returned is incorrect: %s", id)
-	}
-}
-
-func TestRandomStringUniqueness(t *testing.T) {
-	repeats := 25
-	set := make(map[string]struct{}, repeats)
-	for i := 0; i < repeats; i = i + 1 {
-		id := RandomString()
-		if len(id) != 64 {
-			t.Fatalf("Id returned is incorrect: %s", id)
-		}
-		if _, ok := set[id]; ok {
-			t.Fatalf("Random number is repeated")
-		}
-		set[id] = struct{}{}
-	}
-}

pkg/stringutils/README.md

@@ -0,0 +1 @@
+This package provides helper functions for dealing with strings

pkg/stringutils/stringutils.go

@@ -0,0 +1,43 @@
+package stringutils
+
+import (
+	"crypto/rand"
+	"encoding/hex"
+	"io"
+	mathrand "math/rand"
+	"time"
+)
+
+// Generate 32 chars random string
+func GenerateRandomString() string {
+	id := make([]byte, 32)
+
+	if _, err := io.ReadFull(rand.Reader, id); err != nil {
+		panic(err) // This shouldn't happen
+	}
+	return hex.EncodeToString(id)
+}
+
+// Generate alpha only random stirng with length n
+func GenerateRandomAlphaOnlyString(n int) string {
+	// make a really long string
+	letters := []byte("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ")
+	b := make([]byte, n)
+	r := mathrand.New(mathrand.NewSource(time.Now().UTC().UnixNano()))
+	for i := range b {
+		b[i] = letters[r.Intn(len(letters))]
+	}
+	return string(b)
+}
+
+// Generate Ascii random stirng with length n
+func GenerateRandomAsciiString(n int) string {
+	chars := "abcdefghijklmnopqrstuvwxyz" +
+		"ABCDEFGHIJKLMNOPQRSTUVWXYZ" +
+		"~!@#$%^&*()-_+={}[]\\|<,>.?/\"';:` "
+	res := make([]byte, n)
+	for i := 0; i < n; i++ {
+		res[i] = chars[mathrand.Intn(len(chars))]
+	}
+	return string(res)
+}

pkg/stringutils/stringutils_test.go

@@ -0,0 +1,25 @@
+package stringutils
+
+import "testing"
+
+func TestRandomString(t *testing.T) {
+	str := GenerateRandomString()
+	if len(str) != 64 {
+		t.Fatalf("Id returned is incorrect: %s", str)
+	}
+}
+
+func TestRandomStringUniqueness(t *testing.T) {
+	repeats := 25
+	set := make(map[string]struct{}, repeats)
+	for i := 0; i < repeats; i = i + 1 {
+		str := GenerateRandomString()
+		if len(str) != 64 {
+			t.Fatalf("Id returned is incorrect: %s", str)
+		}
+		if _, ok := set[str]; ok {
+			t.Fatalf("Random number is repeated")
+		}
+		set[str] = struct{}{}
+	}
+}

pkg/truncindex/truncindex_test.go

@@ -4,7 +4,7 @@ import (
 	"math/rand"
 	"testing"
 
-	"github.com/docker/docker/pkg/common"
+	"github.com/docker/docker/pkg/stringid"
 )
 
 // 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, common.GenerateRandomID())
+		testSet = append(testSet, stringid.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, common.GenerateRandomID())
+		testSet = append(testSet, stringid.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, common.GenerateRandomID())
+		testSet = append(testSet, stringid.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, common.GenerateRandomID())
+		testSet = append(testSet, stringid.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, common.GenerateRandomID())
+		testSet = append(testSet, stringid.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, common.GenerateRandomID())
+		testSet = append(testSet, stringid.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, common.GenerateRandomID())
+		testSet = append(testSet, stringid.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, common.GenerateRandomID())
+		testSet = append(testSet, stringid.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, common.GenerateRandomID())
+		testSet = append(testSet, stringid.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, common.GenerateRandomID())
+		testSet = append(testSet, stringid.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, common.GenerateRandomID())
+		testSet = append(testSet, stringid.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, common.GenerateRandomID())
+		testSet = append(testSet, stringid.GenerateRandomID())
 	}
 	b.ResetTimer()
 	for i := 0; i < b.N; i++ {
@@ -334,7 +334,7 @@ func BenchmarkTruncIndexAddGet100(b *testing.B) {
 	var testSet []string
 	var testKeys []string
 	for i := 0; i < 500; i++ {
-		id := common.GenerateRandomID()
+		id := stringid.GenerateRandomID()
 		testSet = append(testSet, id)
 		l := rand.Intn(12) + 12
 		testKeys = append(testKeys, id[:l])
@@ -359,7 +359,7 @@ func BenchmarkTruncIndexAddGet250(b *testing.B) {
 	var testSet []string
 	var testKeys []string
 	for i := 0; i < 500; i++ {
-		id := common.GenerateRandomID()
+		id := stringid.GenerateRandomID()
 		testSet = append(testSet, id)
 		l := rand.Intn(12) + 12
 		testKeys = append(testKeys, id[:l])
@@ -384,7 +384,7 @@ func BenchmarkTruncIndexAddGet500(b *testing.B) {
 	var testSet []string
 	var testKeys []string
 	for i := 0; i < 500; i++ {
-		id := common.GenerateRandomID()
+		id := stringid.GenerateRandomID()
 		testSet = append(testSet, id)
 		l := rand.Intn(12) + 12
 		testKeys = append(testKeys, id[:l])

utils/utils.go

@@ -21,9 +21,9 @@ import (
 	log "github.com/Sirupsen/logrus"
 	"github.com/docker/docker/autogen/dockerversion"
 	"github.com/docker/docker/pkg/archive"
-	"github.com/docker/docker/pkg/common"
 	"github.com/docker/docker/pkg/fileutils"
 	"github.com/docker/docker/pkg/ioutils"
+	"github.com/docker/docker/pkg/stringutils"
 )
 
 type KeyValuePair struct {
@@ -312,7 +312,7 @@ var globalTestID string
 // new directory.
 func TestDirectory(templateDir string) (dir string, err error) {
 	if globalTestID == "" {
-		globalTestID = common.RandomString()[:4]
+		globalTestID = stringutils.GenerateRandomString()[:4]
 	}
 	prefix := fmt.Sprintf("docker-test%s-%s-", globalTestID, GetCallerName(2))
 	if prefix == "" {

volumes/repository.go

@@ -9,7 +9,7 @@ import (
 
 	log "github.com/Sirupsen/logrus"
 	"github.com/docker/docker/daemon/graphdriver"
-	"github.com/docker/docker/pkg/common"
+	"github.com/docker/docker/pkg/stringid"
 )
 
 type Repository struct {
@@ -43,7 +43,7 @@ func (r *Repository) newVolume(path string, writable bool) (*Volume, error) {
 	var (
 		isBindMount bool
 		err         error
-		id          = common.GenerateRandomID()
+		id          = stringid.GenerateRandomID()
 	)
 	if path != "" {
 		isBindMount = true