RecyclableVolumePlugin interfaces

pkg/volume/plugins.go

@@ -79,6 +79,15 @@ type PersistentVolumePlugin interface {
 	GetAccessModes() []api.PersistentVolumeAccessMode
 }
 
+// RecyclableVolumePlugin is an extended interface of VolumePlugin and is used
+// by persistent volumes that want to be recycled before being made available again to new claims
+type RecyclableVolumePlugin interface {
+	VolumePlugin
+	// NewRecycler creates a new volume.Recycler which knows how to reclaim this resource
+	// after the volume's release from a PersistentVolumeClaim
+	NewRecycler(spec *Spec) (Recycler, error)
+}
+
 // VolumeHost is an interface that plugins can use to access the kubelet.
 type VolumeHost interface {
 	// GetPluginDir returns the absolute path to a directory under which
@@ -217,7 +226,20 @@ func (pm *VolumePluginMgr) FindPluginByName(name string) (VolumePlugin, error) {
 	return pm.plugins[matches[0]], nil
 }
 
-// FindPluginByName fetches a plugin by name or by legacy name.  If no plugin
+// FindPersistentPluginBySpec looks for a persistent volume plugin that can support a given volume
+// specification.  If no plugin is found, return an error
+func (pm *VolumePluginMgr) FindPersistentPluginBySpec(spec *Spec) (PersistentVolumePlugin, error) {
+	volumePlugin, err := pm.FindPluginBySpec(spec)
+	if err != nil {
+		return nil, fmt.Errorf("Could not find volume plugin for spec: %+v", spec)
+	}
+	if persistentVolumePlugin, ok := volumePlugin.(PersistentVolumePlugin); ok {
+		return persistentVolumePlugin, nil
+	}
+	return nil, fmt.Errorf("no persistent volume plugin matched")
+}
+
+// FindPersistentPluginByName fetches a persistent volume plugin by name.  If no plugin
 // is found, returns error.
 func (pm *VolumePluginMgr) FindPersistentPluginByName(name string) (PersistentVolumePlugin, error) {
 	volumePlugin, err := pm.FindPluginByName(name)
@@ -227,5 +249,18 @@ func (pm *VolumePluginMgr) FindPersistentPluginByName(name string) (PersistentVo
 	if persistentVolumePlugin, ok := volumePlugin.(PersistentVolumePlugin); ok {
 		return persistentVolumePlugin, nil
 	}
-	return nil, fmt.Errorf("no persistent volume plugin matched")
+	return nil, fmt.Errorf("no persistent volume plugin matched: %+v")
+}
+
+// FindRecyclablePluginByName fetches a persistent volume plugin by name.  If no plugin
+// is found, returns error.
+func (pm *VolumePluginMgr) FindRecyclablePluginBySpec(spec *Spec) (RecyclableVolumePlugin, error) {
+	volumePlugin, err := pm.FindPluginBySpec(spec)
+	if err != nil {
+		return nil, err
+	}
+	if recyclableVolumePlugin, ok := volumePlugin.(RecyclableVolumePlugin); ok {
+		return recyclableVolumePlugin, nil
+	}
+	return nil, fmt.Errorf("no recyclable volume plugin matched")
 }

pkg/volume/testing.go

@@ -82,6 +82,7 @@ type FakeVolumePlugin struct {
 }
 
 var _ VolumePlugin = &FakeVolumePlugin{}
+var _ RecyclableVolumePlugin = &FakeVolumePlugin{}
 
 func (plugin *FakeVolumePlugin) Init(host VolumeHost) {
 	plugin.Host = host
@@ -104,6 +105,10 @@ func (plugin *FakeVolumePlugin) NewCleaner(volName string, podUID types.UID, mou
 	return &FakeVolume{podUID, volName, plugin}, nil
 }
 
+func (plugin *FakeVolumePlugin) NewRecycler(spec *Spec) (Recycler, error) {
+	return &FakeRecycler{"/attributesTransferredFromSpec"}, nil
+}
+
 func (plugin *FakeVolumePlugin) GetAccessModes() []api.PersistentVolumeAccessMode {
 	return []api.PersistentVolumeAccessMode{}
 }
@@ -133,3 +138,16 @@ func (fv *FakeVolume) TearDown() error {
 func (fv *FakeVolume) TearDownAt(dir string) error {
 	return os.RemoveAll(dir)
 }
+
+type FakeRecycler struct {
+	path string
+}
+
+func (fr *FakeRecycler) Recycle() error {
+	// nil is success, else error
+	return nil
+}
+
+func (fr *FakeRecycler) GetPath() string {
+	return fr.path
+}

pkg/volume/volume.go

@@ -29,7 +29,7 @@ type Volume interface {
 	GetPath() string
 }
 
-// Builder interface provides method to set up/mount the volume.
+// Builder interface provides methods to set up/mount the volume.
 type Builder interface {
 	// Uses Interface to provide the path for Docker binds.
 	Volume
@@ -43,7 +43,7 @@ type Builder interface {
 	SetUpAt(dir string) error
 }
 
-// Cleaner interface provides method to cleanup/unmount the volumes.
+// Cleaner interface provides methods to cleanup/unmount the volumes.
 type Cleaner interface {
 	Volume
 	// TearDown unmounts the volume from a self-determined directory and
@@ -54,6 +54,14 @@ type Cleaner interface {
 	TearDownAt(dir string) error
 }
 
+// Recycler provides methods to reclaim the volume resource.
+type Recycler interface {
+	Volume
+	// Recycle reclaims the resource.  Calls to this method should block until the recycling task is complete.
+	// Any error returned indicates the volume has failed to be reclaimed.  A nil return indicates success.
+	Recycle() error
+}
+
 func RenameDirectory(oldPath, newName string) (string, error) {
 	newPath, err := ioutil.TempDir(path.Dir(oldPath), newName)
 	if err != nil {