Add GetIntreeNameFromCSIName and SupersedesInTreePlugin APIs and unit tests

Signed-off-by: Deep Debroy <ddebroy@docker.com>

pkg/controller/volume/persistentvolume/pv_controller.go

@@ -1355,7 +1355,7 @@ func (ctrl *PersistentVolumeController) getCSINameFromIntreeName(pluginName stri
 	if ctrl.csiNameFromIntreeNameHook != nil {
 		return ctrl.csiNameFromIntreeNameHook(pluginName)
 	}
-	return csitranslation.GetCSINameFromIntreeName(pluginName)
+	return csitranslation.GetCSINameFromInTreeName(pluginName)
 }
 
 // provisionClaimOperation provisions a volume. This method is running in

staging/src/k8s.io/csi-translation-lib/plugins/aws_ebs.go

@@ -108,3 +108,8 @@ func (t *awsElasticBlockStoreCSITranslator) CanSupport(pv *v1.PersistentVolume)
 func (t *awsElasticBlockStoreCSITranslator) GetInTreePluginName() string {
 	return AWSEBSInTreePluginName
 }
+
+// GetCSIPluginName returns the name of the CSI plugin
+func (t *awsElasticBlockStoreCSITranslator) GetCSIPluginName() string {
+	return AWSEBSDriverName
+}

staging/src/k8s.io/csi-translation-lib/plugins/gce_pd.go

@@ -149,6 +149,11 @@ func (g *gcePersistentDiskCSITranslator) GetInTreePluginName() string {
 	return GCEPDInTreePluginName
 }
 
+// GetCSIPluginName returns the name of the CSI plugin
+func (g *gcePersistentDiskCSITranslator) GetCSIPluginName() string {
+	return GCEPDDriverName
+}
+
 func pdNameFromVolumeID(id string) (string, error) {
 	splitID := strings.Split(id, "/")
 	if len(splitID) != volIDTotalElements {

staging/src/k8s.io/csi-translation-lib/plugins/in_tree_volume.go

@@ -40,4 +40,7 @@ type InTreePlugin interface {
 
 	// GetInTreePluginName returns the in-tree plugin name this migrates
 	GetInTreePluginName() string
+
+	// GetCSIPluginName returns the name of the CSI plugin that supersedes the in-tree plugin
+	GetCSIPluginName() string
 }

staging/src/k8s.io/csi-translation-lib/plugins/openstack_cinder.go

@@ -96,3 +96,8 @@ func (t *osCinderCSITranslator) CanSupport(pv *v1.PersistentVolume) bool {
 func (t *osCinderCSITranslator) GetInTreePluginName() string {
 	return CinderInTreePluginName
 }
+
+// GetCSIPluginName returns the name of the CSI plugin
+func (t *osCinderCSITranslator) GetCSIPluginName() string {
+	return CinderDriverName
+}

staging/src/k8s.io/csi-translation-lib/translate.go

@@ -76,18 +76,27 @@ func TranslateCSIPVToInTree(pv *v1.PersistentVolume) (*v1.PersistentVolume, erro
 }
 
 // IsMigratableByName tests whether there is Migration logic for the in-tree plugin
-// for the given `pluginName`
-func IsMigratableByName(pluginName string) bool {
+// whose name matches the given inTreePluginName
+func IsMigratableByName(inTreePluginName string) bool {
 	for _, curPlugin := range inTreePlugins {
-		if curPlugin.GetInTreePluginName() == pluginName {
+		if curPlugin.GetInTreePluginName() == inTreePluginName {
 			return true
 		}
 	}
 	return false
 }
 
-// GetCSINameFromIntreeName maps the name of a CSI driver to its in-tree version
-func GetCSINameFromIntreeName(pluginName string) (string, error) {
+// SupersedesInTreePlugin tests whether there exists an in-tree plugin with logic
+// to migrate to the CSI plugin with given name
+func SupersedesInTreePlugin(csiPluginName string) bool {
+	if _, ok := inTreePlugins[csiPluginName]; ok {
+		return true
+	}
+	return false
+}
+
+// GetCSINameFromInTreeName returns the name of a CSI driver that supersedes the in-tree plugin with the given name
+func GetCSINameFromInTreeName(pluginName string) (string, error) {
 	for csiDriverName, curPlugin := range inTreePlugins {
 		if curPlugin.GetInTreePluginName() == pluginName {
 			return csiDriverName, nil
@@ -96,7 +105,15 @@ func GetCSINameFromIntreeName(pluginName string) (string, error) {
 	return "", fmt.Errorf("Could not find CSI Driver name for plugin %v", pluginName)
 }
 
-// IsPVMigratable tests whether there is Migration logic for the given Persistent Volume
+// GetInTreeNameFromCSIName returns the name of the in-tree plugin superseded by a CSI driver with the given name
+func GetInTreeNameFromCSIName(pluginName string) (string, error) {
+	if plugin, ok := inTreePlugins[pluginName]; ok {
+		return plugin.GetInTreePluginName(), nil
+	}
+	return "", fmt.Errorf("Could not find In-Tree driver name for CSI plugin %v", pluginName)
+}
+
+// IsPVMigratable tests whether there is migration logic for the given Persistent Volume
 func IsPVMigratable(pv *v1.PersistentVolume) bool {
 	for _, curPlugin := range inTreePlugins {
 		if curPlugin.CanSupport(pv) {

staging/src/k8s.io/csi-translation-lib/translate_test.go

@@ -76,4 +76,43 @@ func TestTranslationStability(t *testing.T) {
 	}
 }
 
+func TestPluginNameMappings(t *testing.T) {
+	testCases := []struct {
+		name             string
+		inTreePluginName string
+		csiPluginName    string
+	}{
+		{
+			name:             "GCE PD plugin name",
+			inTreePluginName: "kubernetes.io/gce-pd",
+			csiPluginName:    "pd.csi.storage.gke.io",
+		},
+		{
+			name:             "AWS EBS plugin name",
+			inTreePluginName: "kubernetes.io/aws-ebs",
+			csiPluginName:    "ebs.csi.aws.com",
+		},
+	}
+	for _, test := range testCases {
+		t.Logf("Testing %v", test.name)
+		csiPluginName, err := GetCSINameFromInTreeName(test.inTreePluginName)
+		if err != nil {
+			t.Errorf("Error when mapping In-tree plugin name to CSI plugin name %s", err)
+		}
+		if !SupersedesInTreePlugin(csiPluginName) {
+			t.Errorf("%s expected to supersede an In-tree plugin", csiPluginName)
+		}
+		inTreePluginName, err := GetInTreeNameFromCSIName(csiPluginName)
+		if err != nil {
+			t.Errorf("Error when mapping CSI plugin name to In-tree plugin name %s", err)
+		}
+		if !IsMigratableByName(inTreePluginName) {
+			t.Errorf("%s expected to be migratable to a CSI name", inTreePluginName)
+		}
+		if inTreePluginName != test.inTreePluginName || csiPluginName != test.csiPluginName {
+			t.Errorf("CSI plugin name and In-tree plugin name do not map to each other: [%s => %s], [%s => %s]", test.csiPluginName, inTreePluginName, test.inTreePluginName, csiPluginName)
+		}
+	}
+}
+
 // TODO: test for not modifying the original PV.