rkt: Implement ImageStats() for rkt.

pkg/kubelet/rkt/image.go

@@ -227,3 +227,17 @@ func (r *Runtime) writeDockerAuthConfig(image string, credsSlice []credentialpro
 	}
 	return nil
 }
+
+// ImageStats returns the image stat (total storage bytes).
+func (r *Runtime) ImageStats() (*kubecontainer.ImageStats, error) {
+	var imageStat kubecontainer.ImageStats
+	listResp, err := r.apisvc.ListImages(context.Background(), &rktapi.ListImagesRequest{})
+	if err != nil {
+		return nil, fmt.Errorf("couldn't list images: %v", err)
+	}
+
+	for _, image := range listResp.Images {
+		imageStat.TotalStorageBytes = imageStat.TotalStorageBytes + uint64(image.Size)
+	}
+	return &imageStat, nil
+}

pkg/kubelet/rkt/rkt.go

@@ -1771,8 +1771,3 @@ func (r *Runtime) GetPodStatus(uid types.UID, name, namespace string) (*kubecont
 
 	return podStatus, nil
 }
-
-// FIXME: I need to be implemented.
-func (r *Runtime) ImageStats() (*kubecontainer.ImageStats, error) {
-	return &kubecontainer.ImageStats{}, nil
-}

pkg/kubelet/rkt/rkt_test.go

@@ -1382,3 +1382,18 @@ func TestLifeCycleHooks(t *testing.T) {
 		runner.Reset()
 	}
 }
+
+func TestImageStats(t *testing.T) {
+	fr := newFakeRktInterface()
+	rkt := &Runtime{apisvc: fr}
+
+	fr.images = []*rktapi.Image{
+		{Size: 100},
+		{Size: 200},
+		{Size: 300},
+	}
+
+	result, err := rkt.ImageStats()
+	assert.NoError(t, err)
+	assert.Equal(t, result, &kubecontainer.ImageStats{TotalStorageBytes: 600})
+}