Store application namespace as an annotation

This helps when an ApplicationSet is deleted prior to actual
drpc deletion, as the application namespace, and VRG naming
using the same, can continue to find the required resources to
delete and cleanup.

Signed-off-by: Shyamsundar Ranganathan <srangana@redhat.com>

controllers/drplacementcontrol.go

@@ -33,6 +33,9 @@ const (
 
 	// Annotation for the last cluster on which the application was running
 	LastAppDeploymentCluster = "drplacementcontrol.ramendr.openshift.io/last-app-deployment-cluster"
+
+	// Annotation for application namespace on the managed cluster
+	DRPCAppNamespace = "drplacementcontrol.ramendr.openshift.io/app-namespace"
 )
 
 var (

controllers/drplacementcontrol_controller.go

@@ -923,23 +923,32 @@ func (r *DRPlacementControlReconciler) getDRPolicy(ctx context.Context,
 	return drPolicy, nil
 }
 
-func (r DRPlacementControlReconciler) addLabelsAndFinalizers(ctx context.Context,
+// updateObjectMetadata updates drpc labels, annotations and finalizer, and also updates placementObj finalizer
+func (r DRPlacementControlReconciler) updateObjectMetadata(ctx context.Context,
 	drpc *rmn.DRPlacementControl, placementObj client.Object, log logr.Logger,
 ) error {
-	// add label and finalizer to DRPC
-	labelAdded := rmnutil.AddLabel(drpc, rmnutil.OCMBackupLabelKey, rmnutil.OCMBackupLabelValue)
-	finalizerAdded := rmnutil.AddFinalizer(drpc, DRPCFinalizer)
+	update := false
 
-	if labelAdded || finalizerAdded {
+	update = rmnutil.AddLabel(drpc, rmnutil.OCMBackupLabelKey, rmnutil.OCMBackupLabelValue)
+	update = rmnutil.AddFinalizer(drpc, DRPCFinalizer) || update
+
+	vrgNamespace, err := selectVRGNamespace(r.Client, r.Log, drpc, placementObj)
+	if err != nil {
+		return err
+	}
+
+	update = rmnutil.AddAnnotation(drpc, DRPCAppNamespace, vrgNamespace) || update
+
+	if update {
 		if err := r.Update(ctx, drpc); err != nil {
-			log.Error(err, "Failed to add label and finalizer to drpc")
+			log.Error(err, "Failed to add annotations, labels, or finalizer to drpc")
 
 			return fmt.Errorf("%w", err)
 		}
 	}
 
 	// add finalizer to User PlacementRule/Placement
-	finalizerAdded = rmnutil.AddFinalizer(placementObj, DRPCFinalizer)
+	finalizerAdded := rmnutil.AddFinalizer(placementObj, DRPCFinalizer)
 	if finalizerAdded {
 		if err := r.Update(ctx, placementObj); err != nil {
 			log.Error(err, "Failed to add finalizer to user placement rule")
@@ -1147,7 +1156,7 @@ func (r *DRPlacementControlReconciler) updateAndSetOwner(
 		return false, err
 	}
 
-	if err := r.addLabelsAndFinalizers(ctx, drpc, usrPlacement, log); err != nil {
+	if err := r.updateObjectMetadata(ctx, drpc, usrPlacement, log); err != nil {
 		return false, err
 	}
 
@@ -1960,6 +1969,10 @@ func selectVRGNamespace(
 	drpc *rmn.DRPlacementControl,
 	placementObj client.Object,
 ) (string, error) {
+	if drpc.GetAnnotations() != nil && drpc.GetAnnotations()[DRPCAppNamespace] != "" {
+		return drpc.GetAnnotations()[DRPCAppNamespace], nil
+	}
+
 	switch placementObj.(type) {
 	case *clrapiv1beta1.Placement:
 		vrgNamespace, err := getApplicationDestinationNamespace(client, log, placementObj)

controllers/drplacementcontrol_controller_test.go

@@ -1705,6 +1705,7 @@ func verifyInitialDRPCDeployment(userPlacement client.Object, preferredCluster s
 	_, condition := getDRPCCondition(&latestDRPC.Status, rmn.ConditionAvailable)
 	Expect(condition.Reason).To(Equal(string(rmn.Deployed)))
 	Expect(latestDRPC.GetAnnotations()[controllers.LastAppDeploymentCluster]).To(Equal(preferredCluster))
+	Expect(latestDRPC.GetAnnotations()[controllers.DRPCAppNamespace]).To(Equal(getVRGNameSpace()))
 }
 
 func verifyFailoverToSecondary(placementObj client.Object, toCluster string,

controllers/util/misc.go

@@ -72,6 +72,24 @@ func AddLabel(obj client.Object, key, value string) bool {
 	return !labelAdded
 }
 
+func AddAnnotation(obj client.Object, key, value string) bool {
+	const added = true
+
+	annotations := obj.GetAnnotations()
+	if annotations == nil {
+		annotations = map[string]string{}
+	}
+
+	if keyValue, ok := annotations[key]; !ok || keyValue != value {
+		annotations[key] = value
+		obj.SetAnnotations(annotations)
+
+		return added
+	}
+
+	return !added
+}
+
 func AddFinalizer(obj client.Object, finalizer string) bool {
 	const finalizerAdded = true