Add status tracker for Docker remote push

Update push client to use status tracker

Signed-off-by: Derek McGowan <derek@mcgstyle.net>

remotes/docker/resolver.go

@@ -38,6 +38,7 @@ type dockerResolver struct {
 	credentials func(string) (string, string, error)
 	plainHTTP   bool
 	client      *http.Client
+	tracker     StatusTracker
 }
 
 // ResolverOptions are used to configured a new Docker register resolver
@@ -53,15 +54,23 @@ type ResolverOptions struct {
 	// Client is the http client to used when making registry requests
 	Client *http.Client
 
-	// TODO: Add upload status tracker
+	// Tracker is used to track uploads to the registry. This is used
+	// since the registry does not have upload tracking and the existing
+	// mechanism for getting blob upload status is expensive.
+	Tracker StatusTracker
 }
 
 // NewResolver returns a new resolver to a Docker registry
 func NewResolver(options ResolverOptions) remotes.Resolver {
+	tracker := options.Tracker
+	if tracker == nil {
+		tracker = NewInMemoryTracker()
+	}
 	return &dockerResolver{
 		credentials: options.Credentials,
 		plainHTTP:   options.PlainHTTP,
 		client:      options.Client,
+		tracker:     tracker,
 	}
 }
 
@@ -214,13 +223,13 @@ func (r *dockerResolver) Pusher(ctx context.Context, ref string) (remotes.Pusher
 	return dockerPusher{
 		dockerBase: base,
 		tag:        refspec.Object,
+		tracker:    r.tracker,
 	}, nil
 }
 
 type dockerBase struct {
-	base    url.URL
-	locator string
-	token   string
+	base  url.URL
+	token string
 
 	client   *http.Client
 	useBasic bool
@@ -260,7 +269,6 @@ func (r *dockerResolver) base(refspec reference.Spec) (*dockerBase, error) {
 
 	return &dockerBase{
 		base:     base,
-		locator:  refspec.Locator,
 		client:   r.client,
 		username: username,
 		secret:   secret,