fix: add check for existence of HTTPRoute in KongUpstreamPolicy controller

CHANGELOG.md

@@ -94,6 +94,9 @@ Adding a new version? You'll need three changes:
   [#5737](https://github.com/Kong/kubernetes-ingress-controller/issues/5737)
 - Set proper User-Agent for request made to Kong and Konnect.
   [#5753](https://github.com/Kong/kubernetes-ingress-controller/pull/5753)
+- `KongUpstreamPolicy` controller no longer requires existence of `HTTPRoute` CRD
+  to start.
+  [#5780](https://github.com/Kong/kubernetes-ingress-controller/pull/5780)
 
 ## [3.1.2]
 

internal/controllers/configuration/kongupstreampolicy_controller.go

@@ -71,15 +71,6 @@ func (r *KongUpstreamPolicyReconciler) SetupWithManager(mgr ctrl.Manager) error
 		return err
 	}
 
-	// Watch for HTTPRoute changes to trigger reconciliation for the KongUpstreamPolicies referenced by the Services
-	// of the HTTPRoute.
-	if err := c.Watch(
-		source.Kind(mgr.GetCache(), &gatewayapi.HTTPRoute{}),
-		handler.EnqueueRequestsFromMapFunc(r.getUpstreamPoliciesForHTTPRouteServices),
-	); err != nil {
-		return err
-	}
-
 	if r.KongServiceFacadeEnabled {
 		if err := c.Watch(
 			source.Kind(mgr.GetCache(), &incubatorv1alpha1.KongServiceFacade{}),
@@ -136,15 +127,6 @@ func (r *KongUpstreamPolicyReconciler) setupIndices(mgr ctrl.Manager) error {
 		return fmt.Errorf("failed to index services on annotation %s: %w", kongv1beta1.KongUpstreamPolicyAnnotationKey, err)
 	}
 
-	if err := mgr.GetCache().IndexField(
-		context.Background(),
-		&gatewayapi.HTTPRoute{},
-		routeBackendRefServiceNameIndexKey,
-		indexRoutesOnBackendRefServiceName,
-	); err != nil {
-		return fmt.Errorf("failed to index HTTPRoutes on backendReferences: %w", err)
-	}
-
 	if r.KongServiceFacadeEnabled {
 		if err := mgr.GetCache().IndexField(
 			context.Background(),
@@ -381,3 +363,44 @@ func (r *KongUpstreamPolicyReconciler) Reconcile(ctx context.Context, req ctrl.R
 func (r *KongUpstreamPolicyReconciler) SetLogger(l logr.Logger) {
 	r.Log = l
 }
+
+type HTTPRouteReconcilerForKongUpstreamPolicy struct {
+	Reconciler *KongUpstreamPolicyReconciler
+}
+
+func (r *HTTPRouteReconcilerForKongUpstreamPolicy) SetupWithManager(mgr ctrl.Manager) error {
+	c, err := controller.New("HTTPRouteForKongUpstreamPolicy", mgr, controller.Options{
+		Reconciler: r.Reconciler,
+		LogConstructor: func(_ *reconcile.Request) logr.Logger {
+			return r.Reconciler.Log
+		},
+		CacheSyncTimeout: r.Reconciler.CacheSyncTimeout,
+	})
+	if err != nil {
+		return err
+	}
+
+	if err := mgr.GetCache().IndexField(
+		context.Background(),
+		&gatewayapi.HTTPRoute{},
+		routeBackendRefServiceNameIndexKey,
+		indexRoutesOnBackendRefServiceName,
+	); err != nil {
+		return fmt.Errorf("failed to index HTTPRoutes on backendReferences: %w", err)
+	}
+
+	// Watch for HTTPRoute changes to trigger reconciliation for the KongUpstreamPolicies referenced by the Services
+	// of the HTTPRoute.
+	if err := c.Watch(
+		source.Kind(mgr.GetCache(), &gatewayapi.HTTPRoute{}),
+		handler.EnqueueRequestsFromMapFunc(r.Reconciler.getUpstreamPoliciesForHTTPRouteServices),
+	); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func (r *HTTPRouteReconcilerForKongUpstreamPolicy) Reconcile(ctx context.Context, req ctrl.Request) (ctrl.Result, error) {
+	return r.Reconciler.Reconcile(ctx, req)
+}

internal/manager/controllerdef.go

@@ -67,6 +67,16 @@ func setupControllers(
 	kongAdminAPIEndpointsNotifier configuration.EndpointsNotifier,
 	adminAPIsDiscoverer configuration.AdminAPIsDiscoverer,
 ) []ControllerDef {
+	kongUpstreamPolicyReconciler := &configuration.KongUpstreamPolicyReconciler{
+		Client:                   mgr.GetClient(),
+		Log:                      ctrl.LoggerFrom(ctx).WithName("controllers").WithName("KongUpstreamPolicy"),
+		Scheme:                   mgr.GetScheme(),
+		DataplaneClient:          dataplaneClient,
+		CacheSyncTimeout:         c.CacheSyncTimeout,
+		KongServiceFacadeEnabled: featureGates.Enabled(featuregates.KongServiceFacade) && c.KongServiceFacadeEnabled,
+		StatusQueue:              kubernetesStatusQueue,
+	}
+
 	controllers := []ControllerDef{
 		// ---------------------------------------------------------------------------
 		// Kong Gateway Admin API Service discovery
@@ -250,11 +260,17 @@ func setupControllers(
 				// StatusQueue:       kubernetesStatusQueue,
 			},
 		},
+		// KongUpstreamPolicy controller without HTTPRoute.
 		{
-			Enabled: c.KongUpstreamPolicyEnabled,
+			Enabled:    c.KongUpstreamPolicyEnabled,
+			Controller: kongUpstreamPolicyReconciler,
+		},
+		// HTTPRoute controller for updating KongUpstreamPolicy's ancestor status with services used as backends of HTTPRoutes.
+		{
+			Enabled: c.KongUpstreamPolicyEnabled && c.GatewayAPIHTTPRouteController,
 			Controller: &crds.DynamicCRDController{
 				Manager:          mgr,
-				Log:              ctrl.LoggerFrom(ctx).WithName("controllers").WithName("Dynamic/KongUpstreamPolicy"),
+				Log:              ctrl.LoggerFrom(ctx).WithName("controllers").WithName("Dynamic/Gateway"),
 				CacheSyncTimeout: c.CacheSyncTimeout,
 				RequiredCRDs: []schema.GroupVersionResource{
 					{
@@ -263,14 +279,8 @@ func setupControllers(
 						Resource: "httproutes",
 					},
 				},
-				Controller: &configuration.KongUpstreamPolicyReconciler{
-					Client:                   mgr.GetClient(),
-					Log:                      ctrl.LoggerFrom(ctx).WithName("controllers").WithName("KongUpstreamPolicy"),
-					Scheme:                   mgr.GetScheme(),
-					DataplaneClient:          dataplaneClient,
-					CacheSyncTimeout:         c.CacheSyncTimeout,
-					KongServiceFacadeEnabled: featureGates.Enabled(featuregates.KongServiceFacade) && c.KongServiceFacadeEnabled,
-					StatusQueue:              kubernetesStatusQueue,
+				Controller: &configuration.HTTPRouteReconcilerForKongUpstreamPolicy{
+					Reconciler: kongUpstreamPolicyReconciler,
 				},
 			},
 		},