feat: Feast Namespaces registry for client ConfigMaps availability (#5599)

* Feast Namespaces registery for client ConfigMaps listing
Remove the registry entry for deleted feature store instance

Signed-off-by: jyejare <[email protected]>

* Dynamic controller namespace

Signed-off-by: jyejare <[email protected]>

* Non namespace handling

Signed-off-by: jyejare <[email protected]>

---------

Signed-off-by: jyejare <[email protected]>

Author: jyejare

infra/feast-operator/docs/namespace-registry.md

@@ -0,0 +1,58 @@
+# Feast Namespace Registry
+
+## Overview
+
+The Feast Namespace Registry is a feature that automatically creates and maintains a centralized ConfigMap containing information about all Feast feature store instances deployed by the operator. This enables dashboard applications and other tools to discover and connect to Feast instances across different namespaces.
+
+## Implementation Details
+
+1. **ConfigMap Creation**: The operator creates a ConfigMap in the appropriate namespace:
+   - **OpenShift AI**: `redhat-ods-applications` namespace (or DSCi configured namespace)
+   - **Kubernetes**: `feast-operator-system` namespace
+
+2. **Access Control**: A RoleBinding is created to allow `system:authenticated` users to read the ConfigMap
+
+3. **Automatic Registration & Cleanup**: When a new feature store instance is created, it automatically registers its namespace and client configuration in the ConfigMap. When deleted, it automatically removes its entry from the ConfigMap
+
+4. **Data Structure**: The ConfigMap contains a JSON structure with namespace names as keys and lists of client configuration names as values
+
+### ConfigMap Structure
+
+The namespace registry ConfigMap (`feast-configs-registry`) contains the following data:
+
+```json
+{
+  "namespaces": {
+    "namespace-1": ["client-config-1", "client-config-2"],
+    "namespace-2": ["client-config-3"]
+  }
+}
+```
+
+### Usage
+
+The namespace registry is automatically deployed when any Feast feature store instance is created. No additional configuration is required.
+
+#### For External Applications
+
+External applications can discover Feast instances by:
+
+1. Reading the ConfigMap from the appropriate namespace:
+   ```bash
+   # For OpenShift
+   kubectl get configmap feast-configs-registry -n redhat-ods-applications -o jsonpath='{.data.namespaces}'
+   
+   # For Kubernetes
+   kubectl get configmap feast-configs-registry -n feast-operator-system -o jsonpath='{.data.namespaces}'
+   ```
+
+### Lifecycle Management
+
+The namespace registry automatically manages the lifecycle of feature store instances:
+
+1. **Creation**: When a feature store is deployed, it registers itself in the ConfigMap
+2. **Updates**: If a feature store is updated, its entry remains in the ConfigMap
+3. **Deletion**: When a feature store is deleted, its entry is automatically removed from the ConfigMap
+4. **Namespace Cleanup**: If all feature stores in a namespace are deleted, the namespace entry is also removed
+
+

infra/feast-operator/internal/controller/featurestore_controller.go

@@ -78,6 +78,16 @@ func (r *FeatureStoreReconciler) Reconcile(ctx context.Context, req ctrl.Request
 		if apierrors.IsNotFound(err) {
 			// CR deleted since request queued, child objects getting GC'd, no requeue
 			logger.V(1).Info("FeatureStore CR not found, has been deleted")
+			// Clean up namespace registry entry even if the CR is not found
+			if err := r.cleanupNamespaceRegistry(ctx, &feastdevv1alpha1.FeatureStore{
+				ObjectMeta: metav1.ObjectMeta{
+					Name:      req.NamespacedName.Name,
+					Namespace: req.NamespacedName.Namespace,
+				},
+			}); err != nil {
+				logger.Error(err, "Failed to clean up namespace registry entry for deleted FeatureStore")
+				// Don't return error here as the CR is already deleted
+			}
 			return ctrl.Result{}, nil
 		}
 		// error fetching FeatureStore instance, requeue and try again
@@ -86,6 +96,16 @@ func (r *FeatureStoreReconciler) Reconcile(ctx context.Context, req ctrl.Request
 	}
 	currentStatus := cr.Status.DeepCopy()
 
+	// Handle deletion - clean up namespace registry entry
+	if cr.DeletionTimestamp != nil {
+		logger.Info("FeatureStore is being deleted, cleaning up namespace registry entry")
+		if err := r.cleanupNamespaceRegistry(ctx, cr); err != nil {
+			logger.Error(err, "Failed to clean up namespace registry entry")
+			return ctrl.Result{}, err
+		}
+		return ctrl.Result{}, nil
+	}
+
 	result, recErr = r.deployFeast(ctx, cr)
 	if cr.DeletionTimestamp == nil && !reflect.DeepEqual(currentStatus, cr.Status) {
 		if err = r.Client.Status().Update(ctx, cr); err != nil {
@@ -102,6 +122,22 @@ func (r *FeatureStoreReconciler) Reconcile(ctx context.Context, req ctrl.Request
 		}
 	}
 
+	// Add to namespace registry if deployment was successful and not being deleted
+	if recErr == nil && cr.DeletionTimestamp == nil {
+		feast := services.FeastServices{
+			Handler: feasthandler.FeastHandler{
+				Client:       r.Client,
+				Context:      ctx,
+				FeatureStore: cr,
+				Scheme:       r.Scheme,
+			},
+		}
+		if err := feast.AddToNamespaceRegistry(); err != nil {
+			logger.Error(err, "Failed to add FeatureStore to namespace registry")
+			// Don't return error here as the FeatureStore is already deployed successfully
+		}
+	}
+
 	return result, recErr
 }
 
@@ -201,6 +237,20 @@ func (r *FeatureStoreReconciler) SetupWithManager(mgr ctrl.Manager) error {
 
 }
 
+// cleanupNamespaceRegistry removes the feature store instance from the namespace registry
+func (r *FeatureStoreReconciler) cleanupNamespaceRegistry(ctx context.Context, cr *feastdevv1alpha1.FeatureStore) error {
+	feast := services.FeastServices{
+		Handler: feasthandler.FeastHandler{
+			Client:       r.Client,
+			Context:      ctx,
+			FeatureStore: cr,
+			Scheme:       r.Scheme,
+		},
+	}
+
+	return feast.RemoveFromNamespaceRegistry()
+}
+
 // if a remotely referenced FeatureStore is changed, reconcile any FeatureStores that reference it.
 func (r *FeatureStoreReconciler) mapFeastRefsToFeastRequests(ctx context.Context, object client.Object) []reconcile.Request {
 	logger := log.FromContext(ctx)