Add csi snapshotter functionality for volume group snapshots

pkg/sidecar-controller/groupsnapshot_helper.go

@@ -0,0 +1,170 @@
+/*
+Copyright 2023 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package sidecar_controller
+
+import (
+	"k8s.io/apimachinery/pkg/api/errors"
+	"k8s.io/client-go/tools/cache"
+	klog "k8s.io/klog/v2"
+
+	crdv1alpha1 "github.com/kubernetes-csi/external-snapshotter/client/v6/apis/volumegroupsnapshot/v1alpha1"
+	"github.com/kubernetes-csi/external-snapshotter/v6/pkg/utils"
+)
+
+func (ctrl *csiSnapshotSideCarController) storeGroupSnapshotContentUpdate(content interface{}) (bool, error) {
+	return utils.StoreObjectUpdate(ctrl.groupSnapshotContentStore, content, "groupsnapshotcontent")
+}
+
+// enqueueGroupSnapshotContentWork adds group snapshot content to given work queue.
+func (ctrl *csiSnapshotSideCarController) enqueueGroupSnapshotContentWork(obj interface{}) {
+	// Beware of "xxx deleted" events
+	if unknown, ok := obj.(cache.DeletedFinalStateUnknown); ok && unknown.Obj != nil {
+		obj = unknown.Obj
+	}
+	if content, ok := obj.(*crdv1alpha1.VolumeGroupSnapshotContent); ok {
+		objName, err := cache.DeletionHandlingMetaNamespaceKeyFunc(content)
+		if err != nil {
+			klog.Errorf("failed to get key from object: %v, %v", err, content)
+			return
+		}
+		klog.V(5).Infof("enqueued %q for sync", objName)
+		ctrl.groupSnapshotContentQueue.Add(objName)
+	}
+}
+
+// groupSnapshotContentWorker processes items from groupSnapshotContentQueue.
+// It must run only once, syncContent is not assured to be reentrant.
+func (ctrl *csiSnapshotSideCarController) groupSnapshotContentWorker() {
+	keyObj, quit := ctrl.groupSnapshotContentQueue.Get()
+	if quit {
+		return
+	}
+	defer ctrl.groupSnapshotContentQueue.Done(keyObj)
+
+	if err := ctrl.syncGroupSnapshotContentByKey(keyObj.(string)); err != nil {
+		// Rather than wait for a full resync, re-add the key to the
+		// queue to be processed.
+		ctrl.groupSnapshotContentQueue.AddRateLimited(keyObj)
+		klog.V(4).Infof("Failed to sync group snapshot content %q, will retry again: %v", keyObj.(string), err)
+		return
+	}
+
+	// Finally, if no error occurs we forget this item so it does not
+	// get queued again until another change happens.
+	ctrl.groupSnapshotContentQueue.Forget(keyObj)
+	return
+}
+
+func (ctrl *csiSnapshotSideCarController) syncGroupSnapshotContentByKey(key string) error {
+	klog.V(5).Infof("syncGroupSnapshotContentByKey[%s]", key)
+
+	_, name, err := cache.SplitMetaNamespaceKey(key)
+	if err != nil {
+		klog.V(4).Infof("error getting name of groupSnapshotContent %q from informer: %v", key, err)
+		return nil
+	}
+	content, err := ctrl.groupSnapshotContentLister.Get(name)
+	// The group snapshot content still exists in informer cache, the event must
+	// have been add/update/sync
+	if err == nil {
+		if ctrl.isDriverMatch(content) {
+			err = ctrl.updateGroupSnapshotContentInInformerCache(content)
+		}
+		if err != nil {
+			// If error occurs we add this item back to the queue
+			return err
+		}
+		return nil
+	}
+	if !errors.IsNotFound(err) {
+		klog.V(2).Infof("error getting group snapshot content %q from informer: %v", key, err)
+		return nil
+	}
+
+	// The content is not in informer cache, the event must have been
+	// "delete"
+	contentObj, found, err := ctrl.groupSnapshotContentStore.GetByKey(key)
+	if err != nil {
+		klog.V(2).Infof("error getting group snapshot content %q from cache: %v", key, err)
+		return nil
+	}
+	if !found {
+		// The controller has already processed the delete event and
+		// deleted the group snapshot content from its cache
+		klog.V(2).Infof("deletion of group snapshot content %q was already processed", key)
+		return nil
+	}
+	content, ok := contentObj.(*crdv1alpha1.VolumeGroupSnapshotContent)
+	if !ok {
+		klog.Errorf("expected group snapshot content, got %+v", content)
+		return nil
+	}
+	ctrl.deleteGroupSnapshotContentInCacheStore(content)
+	return nil
+}
+
+// updateGroupSnapshotContentInInformerCache runs in worker thread and handles
+// "group snapshot content added", "group snapshot content updated" and "periodic
+// sync" events.
+func (ctrl *csiSnapshotSideCarController) updateGroupSnapshotContentInInformerCache(content *crdv1alpha1.VolumeGroupSnapshotContent) error {
+	// Store the new group snapshot content version in the cache and do not process
+	// it if this is an old version.
+	new, err := ctrl.storeGroupSnapshotContentUpdate(content)
+	if err != nil {
+		klog.Errorf("%v", err)
+	}
+	if !new {
+		return nil
+	}
+	err = ctrl.syncGroupSnapshotContent(content)
+	if err != nil {
+		if errors.IsConflict(err) {
+			// Version conflict error happens quite often and the controller
+			// recovers from it easily.
+			klog.V(3).Infof("could not sync group snapshot content %q: %+v", content.Name, err)
+		} else {
+			klog.Errorf("could not sync group snapshot content %q: %+v", content.Name, err)
+		}
+		return err
+	}
+	return nil
+}
+
+// deleteGroupSnapshotContentInCacheStore runs in worker thread and handles "group
+// snapshot content deleted" event.
+func (ctrl *csiSnapshotSideCarController) deleteGroupSnapshotContentInCacheStore(content *crdv1alpha1.VolumeGroupSnapshotContent) {
+	_ = ctrl.groupSnapshotContentStore.Delete(content)
+	klog.V(4).Infof("group snapshot content %q deleted", content.Name)
+}
+
+// syncGroupSnapshotContent deals with one key off the queue.  It returns false when it's time to quit.
+func (ctrl *csiSnapshotSideCarController) syncGroupSnapshotContent(content *crdv1alpha1.VolumeGroupSnapshotContent) error {
+	klog.V(5).Infof("synchronizing VolumeGroupSnapshotContent[%s]", content.Name)
+
+	/*
+		TODO: Check if the group snapshot content should be deleted
+	*/
+
+	/*
+		TODO: Check if a new group snapshot should be created by calling CreateGroupSnapshot
+	*/
+
+	/*
+		TODO: Check and update group snapshot content status
+	*/
+	return nil
+}