@@ -65,7 +65,11 @@ func init() {

 	// Create the "Server"

 	srv := &Server{

-		runtime: runtime,

+		runtime:     runtime,

+		enableCors:  false,

+		lock:        &sync.Mutex{},

+		pullingPool: make(map[string]struct{}),

+		pushingPool: make(map[string]struct{}),

 	}

 	// Retrieve the Image

 	if err := srv.ImagePull(unitTestImageName, "", "", os.Stdout, utils.NewStreamFormatter(false), nil); err != nil {

@@ -15,6 +15,7 @@ import (

 	"path"

 	"runtime"

 	"strings"

+	"sync"

 )

 func (srv *Server) DockerVersion() APIVersion {

@@ -401,7 +402,47 @@ func (srv *Server) pullRepository(r *registry.Registry, out io.Writer, local, re

 	return nil

 }

+func (srv *Server) poolAdd(kind, key string) error {

+	srv.lock.Lock()

+	defer srv.lock.Unlock()

+

+	if _, exists := srv.pullingPool[key]; exists {

+		return fmt.Errorf("%s %s is already in progress", key, kind)

+	}

+

+	switch kind {

+	case "pull":

+		srv.pullingPool[key] = struct{}{}

+		break

+	case "push":

+		srv.pushingPool[key] = struct{}{}

+		break

+	default:

+		return fmt.Errorf("Unkown pool type")

+	}

+	return nil

+}

+

+func (srv *Server) poolRemove(kind, key string) error {

+	switch kind {

+	case "pull":

+		delete(srv.pullingPool, key)

+		break

+	case "push":

+		delete(srv.pushingPool, key)

+		break

+	default:

+		return fmt.Errorf("Unkown pool type")

+	}

+	return nil

+}

+

 func (srv *Server) ImagePull(name, tag, endpoint string, out io.Writer, sf *utils.StreamFormatter, authConfig *auth.AuthConfig) error {

+	if err := srv.poolAdd("pull", name+":"+tag); err != nil {

+		return err

+	}

+	defer srv.poolRemove("pull", name+":"+tag)

+

 	r := registry.NewRegistry(srv.runtime.root, authConfig)

 	out = utils.NewWriteFlusher(out)

 	if endpoint != "" {

@@ -418,7 +459,6 @@ func (srv *Server) ImagePull(name, tag, endpoint string, out io.Writer, sf *util

 	if err := srv.pullRepository(r, out, name, remote, tag, sf); err != nil {

 		return err

 	}

-

 	return nil

 }

@@ -593,7 +633,13 @@ func (srv *Server) pushImage(r *registry.Registry, out io.Writer, remote, imgId,

 	return nil

 }

+// FIXME: Allow to interupt current push when new push of same image is done.

 func (srv *Server) ImagePush(name, endpoint string, out io.Writer, sf *utils.StreamFormatter, authConfig *auth.AuthConfig) error {

+	if err := srv.poolAdd("push", name); err != nil {

+		return err

+	}

+	defer srv.poolRemove("push", name)

+

 	out = utils.NewWriteFlusher(out)

 	img, err := srv.runtime.graph.Get(name)

 	r := registry.NewRegistry(srv.runtime.root, authConfig)

@@ -991,14 +1037,20 @@ func NewServer(autoRestart, enableCors bool, dns ListOpts) (*Server, error) {

 		return nil, err

 	}

 	srv := &Server{

-		runtime:    runtime,

-		enableCors: enableCors,

+		runtime:     runtime,

+		enableCors:  enableCors,

+		lock:        &sync.Mutex{},

+		pullingPool: make(map[string]struct{}),

+		pushingPool: make(map[string]struct{}),

 	}

 	runtime.srv = srv

 	return srv, nil

 }

 type Server struct {

-	runtime    *Runtime

-	enableCors bool

+	runtime     *Runtime

+	enableCors  bool

+	lock        *sync.Mutex

+	pullingPool map[string]struct{}

+	pushingPool map[string]struct{}

 }