fix: use maps for backendRefMappings instead of Sets

internal/provider/kubernetes/controller.go

@@ -603,7 +603,7 @@ func (r *gatewayAPIReconciler) processBackendRefs(ctx context.Context, gwcResour
 	// All other errors are just logged and ignored - these errors result in missing referenced backend resources
 	// in the resource tree, which is acceptable as the Gateway API translation layer will handle them.
 	// The Gateway API translation layer will surface these errors in the status of the resources referencing them.
-	for backendRef := range resourceMappings.allAssociatedBackendRefs {
+	for _, backendRef := range resourceMappings.allAssociatedBackendRefs {
 		backendRefKind := gatewayapi.KindDerefOr(backendRef.Kind, resource.KindService)
 		backendNs, backendName := string(*backendRef.Namespace), string(backendRef.Name)
 		logger := r.log.WithValues("kind", backendRefKind, "namespace", backendNs,
@@ -964,6 +964,27 @@ func getBackendRefs(backendCluster egv1a1.BackendCluster) []gwapiv1.BackendObjec
 	return backendRefs
 }
 
+func backendRefKey(ref *gwapiv1.BackendObjectReference) utils.NamespacedNameWithGroupKind {
+	if ref == nil {
+		return utils.NamespacedNameWithGroupKind{}
+	}
+	namespace := gatewayapi.NamespaceDerefOr(ref.Namespace, "")
+	group := gatewayapi.GroupDerefOr(ref.Group, "")
+	kind := gatewayapi.KindDerefOr(ref.Kind, resource.KindService)
+	return utils.NamespacedNameWithGroupKind{
+		NamespacedName: types.NamespacedName{Namespace: namespace, Name: string(ref.Name)},
+		GroupKind:      schema.GroupKind{Group: group, Kind: kind},
+	}
+}
+
+func (rm *resourceMappings) insertBackendRef(ref gwapiv1.BackendObjectReference) {
+	key := backendRefKey(&ref)
+	if _, exists := rm.allAssociatedBackendRefs[key]; exists {
+		return
+	}
+	rm.allAssociatedBackendRefs[key] = ref
+}
+
 // processBackendRef adds the referenced BackendRef to the resourceMap for later processBackendRefs.
 // If BackendRef exists in a different namespace and there is a ReferenceGrant, adds ReferenceGrant to the resourceTree.
 func (r *gatewayAPIReconciler) processBackendRef(
@@ -976,12 +997,14 @@ func (r *gatewayAPIReconciler) processBackendRef(
 	backendRef gwapiv1.BackendObjectReference,
 ) error {
 	backendNamespace := gatewayapi.NamespaceDerefOr(backendRef.Namespace, ownerNS)
-	resourceMap.allAssociatedBackendRefs.Insert(gwapiv1.BackendObjectReference{
+	normalizedRef := gwapiv1.BackendObjectReference{
 		Group:     backendRef.Group,
 		Kind:      backendRef.Kind,
 		Namespace: gatewayapi.NamespacePtr(backendNamespace),
 		Name:      backendRef.Name,
-	})
+		Port:      backendRef.Port,
+	}
+	resourceMap.insertBackendRef(normalizedRef)
 
 	if backendNamespace != ownerNS {
 		from := ObjectKindNamespacedName{
@@ -1516,7 +1539,7 @@ func (r *gatewayAPIReconciler) processServiceClusterForGatewayClass(ep *egv1a1.E
 		}
 	}
 
-	resourceMap.allAssociatedBackendRefs.Insert(gwapiv1.BackendObjectReference{
+	resourceMap.insertBackendRef(gwapiv1.BackendObjectReference{
 		Kind:      ptr.To(gwapiv1.Kind("Service")),
 		Namespace: gatewayapi.NamespacePtr(proxySvcNamespace),
 		Name:      gwapiv1.ObjectName(proxySvcName),
@@ -1545,7 +1568,7 @@ func (r *gatewayAPIReconciler) processServiceClusterForGateway(ep *egv1a1.EnvoyP
 		}
 	}
 
-	resourceMap.allAssociatedBackendRefs.Insert(gwapiv1.BackendObjectReference{
+	resourceMap.insertBackendRef(gwapiv1.BackendObjectReference{
 		Kind:      ptr.To(gwapiv1.Kind("Service")),
 		Namespace: gatewayapi.NamespacePtr(proxySvcNamespace),
 		Name:      gwapiv1.ObjectName(proxySvcName),
@@ -2456,12 +2479,14 @@ func (r *gatewayAPIReconciler) processEnvoyProxy(ep *egv1a1.EnvoyProxy, resource
 
 		for _, backendRef := range backendRefs {
 			backendNamespace := gatewayapi.NamespaceDerefOr(backendRef.Namespace, ep.Namespace)
-			resourceMap.allAssociatedBackendRefs.Insert(gwapiv1.BackendObjectReference{
+			normalizedRef := gwapiv1.BackendObjectReference{
 				Group:     backendRef.Group,
 				Kind:      backendRef.Kind,
 				Namespace: gatewayapi.NamespacePtr(backendNamespace),
 				Name:      backendRef.Name,
-			})
+				Port:      backendRef.Port,
+			}
+			resourceMap.insertBackendRef(normalizedRef)
 		}
 	}
 

internal/provider/kubernetes/controller_test.go

@@ -303,15 +303,15 @@ func TestProcessBackendRefsWithCustomBackends(t *testing.T) {
 
 			// Create resource mappings
 			resourceMappings := &resourceMappings{
-				allAssociatedBackendRefs:                sets.New[gwapiv1.BackendObjectReference](),
+				allAssociatedBackendRefs:                make(map[utils.NamespacedNameWithGroupKind]gwapiv1.BackendObjectReference),
 				allAssociatedNamespaces:                 sets.New[string](),
 				allAssociatedBackendRefExtensionFilters: sets.New[utils.NamespacedNameWithGroupKind](),
 				extensionRefFilters:                     tc.existingExtFilters,
 			}
 
 			// Add backend refs to the mapping
 			for _, backendRef := range tc.backendRefs {
-				resourceMappings.allAssociatedBackendRefs.Insert(backendRef)
+				resourceMappings.insertBackendRef(backendRef)
 			}
 
 			// Create empty resource tree
@@ -1303,11 +1303,14 @@ func TestProcessServiceClusterForGatewayClass(t *testing.T) {
 
 			r.processServiceClusterForGatewayClass(tc.envoyProxy, tc.gatewayClass, resourceMap)
 
-			require.Contains(t, resourceMap.allAssociatedBackendRefs, gwapiv1.BackendObjectReference{
-				Kind:      ptr.To(gwapiv1.Kind("Service")),
+			expectedRef := gwapiv1.BackendObjectReference{
+				Kind:      ptr.To(gwapiv1.Kind(resource.KindService)),
 				Namespace: gatewayapi.NamespacePtr(r.namespace),
 				Name:      gwapiv1.ObjectName(tc.expectedSvcName),
-			})
+			}
+			key := backendRefKey(&expectedRef)
+			require.Contains(t, resourceMap.allAssociatedBackendRefs, key)
+			require.Equal(t, expectedRef, resourceMap.allAssociatedBackendRefs[key])
 		})
 	}
 }
@@ -1457,11 +1460,14 @@ func TestProcessServiceClusterForGateway(t *testing.T) {
 
 			r.processServiceClusterForGateway(tc.envoyProxy, tc.gateway, resourceMap)
 
-			require.Contains(t, resourceMap.allAssociatedBackendRefs, gwapiv1.BackendObjectReference{
-				Kind:      ptr.To(gwapiv1.Kind("Service")),
+			expectedRef := gwapiv1.BackendObjectReference{
+				Kind:      ptr.To(gwapiv1.Kind(resource.KindService)),
 				Namespace: gatewayapi.NamespacePtr(tc.expectedSvcNamespace),
 				Name:      gwapiv1.ObjectName(tc.expectedSvcName),
-			})
+			}
+			key := backendRefKey(&expectedRef)
+			require.Contains(t, resourceMap.allAssociatedBackendRefs, key)
+			require.Equal(t, expectedRef, resourceMap.allAssociatedBackendRefs[key])
 		})
 	}
 }
@@ -1481,6 +1487,23 @@ func newGatewayAPIReconciler(logger logging.Logger) *gatewayAPIReconciler {
 	}
 }
 
+func TestProcessBackendRefDeduplicatesLogicalBackend(t *testing.T) {
+	logger := logging.DefaultLogger(os.Stdout, egv1a1.LogLevelInfo)
+	r := newGatewayAPIReconciler(logger)
+	resourceTree := resource.NewResources()
+	resourceMap := newResourceMapping()
+
+	backendRef := gwapiv1.BackendObjectReference{
+		Namespace: gatewayapi.NamespacePtr("default"),
+		Name:      "svc",
+	}
+
+	require.NoError(t, r.processBackendRef(t.Context(), resourceMap, resourceTree, resource.KindHTTPRoute, "default", "route-a", backendRef))
+	require.NoError(t, r.processBackendRef(t.Context(), resourceMap, resourceTree, resource.KindHTTPRoute, "default", "route-b", backendRef))
+
+	require.Len(t, resourceMap.allAssociatedBackendRefs, 1)
+}
+
 func TestProcessBackendRefs(t *testing.T) {
 	ns := "default"
 	ctb := test.GetClusterTrustBundle("fake-ctb")
@@ -1584,7 +1607,7 @@ func TestProcessBackendRefs(t *testing.T) {
 			resourceTree := resource.NewResources()
 			resourceMap := newResourceMapping()
 			backend := tc.backend
-			resourceMap.allAssociatedBackendRefs.Insert(gwapiv1.BackendObjectReference{
+			resourceMap.insertBackendRef(gwapiv1.BackendObjectReference{
 				Kind:      gatewayapi.KindPtr(resource.KindBackend),
 				Namespace: gatewayapi.NamespacePtr(backend.Namespace),
 				Name:      gwapiv1.ObjectName(backend.Name),

internal/provider/kubernetes/resource.go

@@ -46,8 +46,8 @@ type resourceMappings struct {
 	allAssociatedTCPRoutes sets.Set[string]
 	// Set for storing UDPRoutes' NamespacedNames attaching to various Gateway objects.
 	allAssociatedUDPRoutes sets.Set[string]
-	// Set for storing backendRefs' BackendObjectReference referred by various Route objects.
-	allAssociatedBackendRefs sets.Set[gwapiv1.BackendObjectReference]
+	// Map caching BackendObjectReferences keyed by their normalized identifier.
+	allAssociatedBackendRefs map[utils.NamespacedNameWithGroupKind]gwapiv1.BackendObjectReference
 	// Set for storing ClientTrafficPolicies' NamespacedNames referred by various Route objects.
 	allAssociatedClientTrafficPolicies sets.Set[string]
 	// Set for storing BackendTrafficPolicies' NamespacedNames referred by various Route objects.
@@ -90,7 +90,7 @@ func newResourceMapping() *resourceMappings {
 		allAssociatedGRPCRoutes:                 sets.New[string](),
 		allAssociatedTCPRoutes:                  sets.New[string](),
 		allAssociatedUDPRoutes:                  sets.New[string](),
-		allAssociatedBackendRefs:                sets.New[gwapiv1.BackendObjectReference](),
+		allAssociatedBackendRefs:                make(map[utils.NamespacedNameWithGroupKind]gwapiv1.BackendObjectReference),
 		allAssociatedClientTrafficPolicies:      sets.New[string](),
 		allAssociatedBackendTrafficPolicies:     sets.New[string](),
 		allAssociatedSecurityPolicies:           sets.New[string](),

internal/provider/kubernetes/routes_test.go

@@ -1302,7 +1302,7 @@ func TestProcessHTTPRoutesWithCustomBackends(t *testing.T) {
 			// Verify results
 			require.NoError(t, err)
 			require.Len(t, resourceMap.extensionRefFilters, tc.expectedExtFiltersCount)
-			require.Equal(t, tc.expectedBackendRefsCount, resourceMap.allAssociatedBackendRefs.Len())
+			require.Len(t, resourceMap.allAssociatedBackendRefs, tc.expectedBackendRefsCount)
 
 			// Verify that HTTPRoutes were processed
 			require.Len(t, resourceTree.HTTPRoutes, 1)