Pushing an Image causes the docker client to give an error message instead of

writing out streamed status.

This is caused by a Buffering message that is not in the correct json format:

[...]
{"status"
:"Pushing 6bba11a28f1ca247de9a47071355ce5923a45b8fea3182389f992f4
24b93edae"}Buffering to disk 244/? (n/a)..
{"status":"Pushing",[...]

The "Buffering to disk" message is originated in
srv.runtime.graph.TempLayerArchive

I am now using the StreamFormatter provided by the context from which the
method is called.

graph.go

@@ -162,7 +162,7 @@ func (graph *Graph) Register(layerData Archive, store bool, img *Image) error {
 //   The archive is stored on disk and will be automatically deleted as soon as has been read.
 //   If output is not nil, a human-readable progress bar will be written to it.
 //   FIXME: does this belong in Graph? How about MktempFile, let the caller use it for archives?
-func (graph *Graph) TempLayerArchive(id string, compression Compression, output io.Writer) (*TempArchive, error) {
+func (graph *Graph) TempLayerArchive(id string, compression Compression,  sf *utils.StreamFormatter, output io.Writer) (*TempArchive, error) {
 	image, err := graph.Get(id)
 	if err != nil {
 		return nil, err
@@ -175,7 +175,6 @@ func (graph *Graph) TempLayerArchive(id string, compression Compression, output
 	if err != nil {
 		return nil, err
 	}
-	sf := utils.NewStreamFormatter(false)
 	return NewTempArchive(utils.ProgressReader(ioutil.NopCloser(archive), 0, output, sf.FormatProgress("Buffering to disk", "%v/%v (%v)"), sf), tmp.Root)
 }
 

server.go

@@ -684,7 +684,7 @@ func (srv *Server) pushImage(r *registry.Registry, out io.Writer, remote, imgID,
 	if err != nil {
 		if os.IsNotExist(err) {
 			// If the archive does not exist, create one from the layer
-			layerData, err = srv.runtime.graph.TempLayerArchive(imgID, Xz, out)
+			layerData, err = srv.runtime.graph.TempLayerArchive(imgID, Xz, sf, out)
 			if err != nil {
 				return fmt.Errorf("Failed to generate layer archive: %s", err)
 			}