Handle stale ReferencingWorkloads in telemetry watch handler (stacklok#4508)

Handle stale ReferencingWorkloads in telemetry watch

The MCPTelemetryConfig watch handler only enqueued the
currently-referenced config when an MCPServer changed. If a
server removed its telemetryConfigRef, the previously-referenced
config was never reconciled to clean up its stale
ReferencingWorkloads entry.

Update the watch handler to also enqueue any MCPTelemetryConfig
that still lists the changed server in ReferencingWorkloads,
matching the pattern already used by MCPOIDCConfig.

Closes stacklok#4491

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: 2 people

cmd/thv-operator/controllers/mcptelemetryconfig_controller.go

@@ -140,26 +140,54 @@ func (r *MCPTelemetryConfigReconciler) Reconcile(ctx context.Context, req ctrl.R
 }
 
 // SetupWithManager sets up the controller with the Manager.
+// Watches MCPServer changes to maintain accurate ReferencingWorkloads status.
 func (r *MCPTelemetryConfigReconciler) SetupWithManager(mgr ctrl.Manager) error {
-	// Watch MCPServer changes to update ReferencingWorkloads status
+	// Watch MCPServer changes to update ReferencingWorkloads on referenced MCPTelemetryConfigs.
+	// This handler enqueues both the currently-referenced MCPTelemetryConfig AND any
+	// MCPTelemetryConfig that still lists this server in ReferencingWorkloads (covers the
+	// case where a server removes its telemetryConfigRef — the previously-referenced
+	// config needs to reconcile and clean up the stale entry).
 	mcpServerHandler := handler.EnqueueRequestsFromMapFunc(
-		func(_ context.Context, obj client.Object) []reconcile.Request {
-			mcpServer, ok := obj.(*mcpv1alpha1.MCPServer)
+		func(ctx context.Context, obj client.Object) []reconcile.Request {
+			server, ok := obj.(*mcpv1alpha1.MCPServer)
 			if !ok {
 				return nil
 			}
 
-			// If this MCPServer references a MCPTelemetryConfig, enqueue it for reconciliation
-			if mcpServer.Spec.TelemetryConfigRef == nil {
-				return nil
+			seen := make(map[types.NamespacedName]struct{})
+			var requests []reconcile.Request
+
+			// Enqueue the currently-referenced MCPTelemetryConfig (if any)
+			if server.Spec.TelemetryConfigRef != nil {
+				nn := types.NamespacedName{
+					Name:      server.Spec.TelemetryConfigRef.Name,
+					Namespace: server.Namespace,
+				}
+				seen[nn] = struct{}{}
+				requests = append(requests, reconcile.Request{NamespacedName: nn})
+			}
+
+			// Also enqueue any MCPTelemetryConfig that still lists this server in
+			// ReferencingWorkloads — handles ref-removal and server-deletion cases.
+			telemetryConfigList := &mcpv1alpha1.MCPTelemetryConfigList{}
+			if err := r.List(ctx, telemetryConfigList, client.InNamespace(server.Namespace)); err != nil {
+				log.FromContext(ctx).Error(err, "Failed to list MCPTelemetryConfigs for MCPServer watch")
+				return requests
+			}
+			for _, cfg := range telemetryConfigList.Items {
+				nn := types.NamespacedName{Name: cfg.Name, Namespace: cfg.Namespace}
+				if _, already := seen[nn]; already {
+					continue
+				}
+				for _, ref := range cfg.Status.ReferencingWorkloads {
+					if ref.Kind == "MCPServer" && ref.Name == server.Name {
+						requests = append(requests, reconcile.Request{NamespacedName: nn})
+						break
+					}
+				}
 			}
 
-			return []reconcile.Request{{
-				NamespacedName: types.NamespacedName{
-					Name:      mcpServer.Spec.TelemetryConfigRef.Name,
-					Namespace: mcpServer.Namespace,
-				},
-			}}
+			return requests
 		},
 	)