controller: removes unnecessary manual caches

internal/controller/controller.go

@@ -44,20 +44,6 @@ type Options struct {
 	ZapOptions           zap.Options
 }
 
-func newClients(config *rest.Config) (kubeClient client.Client, kube kubernetes.Interface, err error) {
-	// TODO: cache options, especially HTTPRoutes managed by the AI Gateway.
-	kubeClient, err = client.New(config, client.Options{Scheme: scheme})
-	if err != nil {
-		return nil, nil, fmt.Errorf("failed to create new client: %w", err)
-	}
-
-	kube, err = kubernetes.NewForConfig(config)
-	if err != nil {
-		return nil, nil, fmt.Errorf("failed to create kubernetes client: %w", err)
-	}
-	return kubeClient, kube, nil
-}
-
 // StartControllers starts the controllers for the AI Gateway.
 // This blocks until the manager is stopped.
 //
@@ -74,37 +60,28 @@ func StartControllers(ctx context.Context, config *rest.Config, logger logr.Logg
 		return fmt.Errorf("failed to create new controller manager: %w", err)
 	}
 
-	clientForRouteC, kubeForRouteC, err := newClients(config)
-	if err != nil {
-		return fmt.Errorf("failed to create new clients: %w", err)
+	c := mgr.GetClient()
+	indexer := mgr.GetFieldIndexer()
+	if err = applyIndexing(indexer); err != nil {
+		return fmt.Errorf("failed to apply indexing: %w", err)
 	}
 
 	sinkChan := make(chan ConfigSinkEvent, 100)
-	routeC := NewLLMRouteController(clientForRouteC, kubeForRouteC, logger, options, sinkChan)
+	routeC := NewLLMRouteController(c, kubernetes.NewForConfigOrDie(config), logger, options, sinkChan)
 	if err = ctrl.NewControllerManagedBy(mgr).
 		For(&aigv1a1.LLMRoute{}).
 		Complete(routeC); err != nil {
 		return fmt.Errorf("failed to create controller for LLMRoute: %w", err)
 	}
 
-	clientForBackendC, kubeForBackendC, err := newClients(config)
-	if err != nil {
-		return fmt.Errorf("failed to create new clients: %w", err)
-	}
-
-	backendC := NewLLMBackendController(clientForBackendC, kubeForBackendC, logger, sinkChan)
+	backendC := NewLLMBackendController(c, kubernetes.NewForConfigOrDie(config), logger, sinkChan)
 	if err = ctrl.NewControllerManagedBy(mgr).
 		For(&aigv1a1.LLMBackend{}).
 		Complete(backendC); err != nil {
 		return fmt.Errorf("failed to create controller for LLMBackend: %w", err)
 	}
 
-	clientForConfigSink, kubeForConfigSink, err := newClients(config)
-	if err != nil {
-		return fmt.Errorf("failed to create new clients: %w", err)
-	}
-
-	sink := newConfigSink(clientForConfigSink, kubeForConfigSink, logger, sinkChan)
+	sink := newConfigSink(c, kubernetes.NewForConfigOrDie(config), logger, sinkChan)
 
 	// Before starting the manager, initialize the config sink to sync all LLMBackend and LLMRoute objects in the cluster.
 	logger.Info("Initializing config sink")
@@ -118,3 +95,12 @@ func StartControllers(ctx context.Context, config *rest.Config, logger logr.Logg
 	}
 	return nil
 }
+
+func applyIndexing(indexer client.FieldIndexer) error {
+	err := indexer.IndexField(context.Background(), &aigv1a1.LLMRoute{},
+		k8sClientIndexBackendToReferencingLLMRoute, llmRouteIndexFunc)
+	if err != nil {
+		return fmt.Errorf("failed to index field for LLMRoute: %w", err)
+	}
+	return nil
+}

internal/controller/llmbackend.go

@@ -37,7 +37,6 @@ func (l *llmBackendController) Reconcile(ctx context.Context, req reconcile.Requ
 	var llmBackend aigv1a1.LLMBackend
 	if err := l.client.Get(ctx, req.NamespacedName, &llmBackend); err != nil {
 		if client.IgnoreNotFound(err) == nil {
-			l.eventChan <- ConfigSinkEventLLMBackendDeleted{namespace: req.Namespace, name: req.Name}
 			l.logger.Info("Deleting LLMBackend",
 				"namespace", req.Namespace, "name", req.Name)
 			return ctrl.Result{}, nil

internal/controller/llmbackend_test.go

@@ -20,21 +20,11 @@ func TestLlmBackendController_Reconcile(t *testing.T) {
 	cl := fake.NewClientBuilder().WithScheme(scheme).Build()
 	c := NewLLMBackendController(cl, fake2.NewClientset(), ctrl.Log, ch)
 
-	// Deleted case.
-	_, err := c.Reconcile(context.Background(), reconcile.Request{NamespacedName: types.NamespacedName{Namespace: "default", Name: "mybackend"}})
-	require.NoError(t, err)
-	item, ok := <-ch
-	require.True(t, ok)
-	require.IsType(t, ConfigSinkEventLLMBackendDeleted{}, item)
-	require.Equal(t, "default", item.(ConfigSinkEventLLMBackendDeleted).namespace)
-	require.Equal(t, "mybackend", item.(ConfigSinkEventLLMBackendDeleted).name)
-
-	// Updated case.
-	err = cl.Create(context.Background(), &aigv1a1.LLMBackend{ObjectMeta: metav1.ObjectMeta{Name: "mybackend", Namespace: "default"}})
+	err := cl.Create(context.Background(), &aigv1a1.LLMBackend{ObjectMeta: metav1.ObjectMeta{Name: "mybackend", Namespace: "default"}})
 	require.NoError(t, err)
 	_, err = c.Reconcile(context.Background(), reconcile.Request{NamespacedName: types.NamespacedName{Namespace: "default", Name: "mybackend"}})
 	require.NoError(t, err)
-	item, ok = <-ch
+	item, ok := <-ch
 	require.True(t, ok)
 	require.IsType(t, &aigv1a1.LLMBackend{}, item)
 	require.Equal(t, "mybackend", item.(*aigv1a1.LLMBackend).Name)

internal/controller/llmroute.go

@@ -22,10 +22,23 @@ import (
 )
 
 const (
-	managedByLabel        = "app.kubernetes.io/managed-by"
-	expProcConfigFileName = "extproc-config.yaml"
+	managedByLabel                             = "app.kubernetes.io/managed-by"
+	expProcConfigFileName                      = "extproc-config.yaml"
+	k8sClientIndexBackendToReferencingLLMRoute = "BackendToReferencingLLMRoute"
 )
 
+func llmRouteIndexFunc(o client.Object) []string {
+	llmRoute := o.(*aigv1a1.LLMRoute)
+	var ret []string
+	for _, rule := range llmRoute.Spec.Rules {
+		for _, backend := range rule.BackendRefs {
+			key := fmt.Sprintf("%s.%s", backend.Name, llmRoute.Namespace)
+			ret = append(ret, key)
+		}
+	}
+	return ret
+}
+
 // llmRouteController implements [reconcile.TypedReconciler].
 //
 // This handles the LLMRoute resource and creates the necessary resources for the external process.
@@ -64,7 +77,6 @@ func (c *llmRouteController) Reconcile(ctx context.Context, req reconcile.Reques
 	var llmRoute aigv1a1.LLMRoute
 	if err := c.client.Get(ctx, req.NamespacedName, &llmRoute); err != nil {
 		if client.IgnoreNotFound(err) == nil {
-			c.eventChan <- ConfigSinkEventLLMRouteDeleted{namespace: req.Namespace, name: req.Name}
 			c.logger.Info("Deleting LLMRoute",
 				"namespace", req.Namespace, "name", req.Name)
 			return ctrl.Result{}, nil

internal/controller/llmroute_test.go

@@ -7,6 +7,7 @@ import (
 	egv1a1 "github.com/envoyproxy/gateway/api/v1alpha1"
 	"github.com/stretchr/testify/require"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/runtime"
 	fake2 "k8s.io/client-go/kubernetes/fake"
 	"sigs.k8s.io/controller-runtime/pkg/client"
 	"sigs.k8s.io/controller-runtime/pkg/client/fake"
@@ -113,3 +114,50 @@ func TestLLMRouteController_reconcileExtProcExtensionPolicy(t *testing.T) {
 		require.Equal(t, llmRoute.Spec.TargetRefs[i].Name, target.Name)
 	}
 }
+
+func Test_llmRouteIndexFunc(t *testing.T) {
+	scheme := runtime.NewScheme()
+	require.NoError(t, aigv1a1.AddToScheme(scheme))
+
+	c := fake.NewClientBuilder().
+		WithScheme(scheme).
+		WithIndex(&aigv1a1.LLMRoute{}, k8sClientIndexBackendToReferencingLLMRoute, llmRouteIndexFunc).
+		Build()
+
+	// Create a LLMRoute.
+	llmRoute := &aigv1a1.LLMRoute{
+		ObjectMeta: metav1.ObjectMeta{
+			Name:      "myroute",
+			Namespace: "default",
+		},
+		Spec: aigv1a1.LLMRouteSpec{
+			TargetRefs: []gwapiv1a2.LocalPolicyTargetReferenceWithSectionName{
+				{LocalPolicyTargetReference: gwapiv1a2.LocalPolicyTargetReference{Name: "mytarget"}},
+				{LocalPolicyTargetReference: gwapiv1a2.LocalPolicyTargetReference{Name: "mytarget2"}},
+			},
+			Rules: []aigv1a1.LLMRouteRule{
+				{
+					Matches: []aigv1a1.LLMRouteRuleMatch{},
+					BackendRefs: []aigv1a1.LLMRouteRuleBackendRef{
+						{Name: "backend1", Weight: 1},
+						{Name: "backend2", Weight: 1},
+					},
+				},
+			},
+		},
+	}
+	require.NoError(t, c.Create(context.Background(), llmRoute))
+
+	var llmRoutes aigv1a1.LLMRouteList
+	err := c.List(context.Background(), &llmRoutes,
+		client.MatchingFields{k8sClientIndexBackendToReferencingLLMRoute: "backend1.default"})
+	require.NoError(t, err)
+	require.Len(t, llmRoutes.Items, 1)
+	require.Equal(t, llmRoute.Name, llmRoutes.Items[0].Name)
+
+	err = c.List(context.Background(), &llmRoutes,
+		client.MatchingFields{k8sClientIndexBackendToReferencingLLMRoute: "backend2.default"})
+	require.NoError(t, err)
+	require.Len(t, llmRoutes.Items, 1)
+	require.Equal(t, llmRoute.Name, llmRoutes.Items[0].Name)
+}

internal/controller/sink.go

@@ -23,24 +23,6 @@ const selectedBackendHeaderKey = "x-envoy-ai-gateway-selected-backend"
 // Exported for internal testing purposes.
 type ConfigSinkEvent any
 
-// ConfigSinkEventLLMBackendDeleted is an event to notify the configSink that an LLMBackend has been deleted.
-//
-// Exported for internal testing purposes.
-type ConfigSinkEventLLMBackendDeleted struct{ namespace, name string }
-
-// String implements fmt.Stringer for testing purposes.
-func (c ConfigSinkEventLLMBackendDeleted) String() string {
-	return fmt.Sprintf("%s.%s", c.name, c.namespace)
-}
-
-// ConfigSinkEventLLMRouteDeleted is an event to notify the configSink that an LLMRoute has been deleted.
-type ConfigSinkEventLLMRouteDeleted struct{ namespace, name string }
-
-// String implements fmt.Stringer for testing purposes.
-func (c ConfigSinkEventLLMRouteDeleted) String() string {
-	return fmt.Sprintf("%s.%s", c.name, c.namespace)
-}
-
 // configSink centralizes the LLMRoute and LLMBackend objects handling
 // which requires to be done in a single goroutine since we need to
 // consolidate the information from both objects to generate the ExtProcConfig
@@ -50,10 +32,7 @@ type configSink struct {
 	kube   kubernetes.Interface
 	logger logr.Logger
 
-	eventChan                   chan ConfigSinkEvent
-	llmRoutes                   map[string]*aigv1a1.LLMRoute
-	backends                    map[string]*aigv1a1.LLMBackend
-	backendsToReferencingRoutes map[string]map[*aigv1a1.LLMRoute]struct{}
+	eventChan chan ConfigSinkEvent
 }
 
 func newConfigSink(
@@ -63,51 +42,25 @@ func newConfigSink(
 	eventChan chan ConfigSinkEvent,
 ) *configSink {
 	c := &configSink{
-		client:                      kubeClient,
-		kube:                        kube,
-		logger:                      logger.WithName("config-sink"),
-		backends:                    make(map[string]*aigv1a1.LLMBackend),
-		llmRoutes:                   make(map[string]*aigv1a1.LLMRoute),
-		backendsToReferencingRoutes: make(map[string]map[*aigv1a1.LLMRoute]struct{}),
-		eventChan:                   eventChan,
+		client:    kubeClient,
+		kube:      kube,
+		logger:    logger.WithName("config-sink"),
+		eventChan: eventChan,
 	}
 	return c
 }
 
+func (c *configSink) backend(namespace, name string) (*aigv1a1.LLMBackend, error) {
+	backend := &aigv1a1.LLMBackend{}
+	if err := c.client.Get(context.Background(), client.ObjectKey{Name: name, Namespace: namespace}, backend); err != nil {
+		return nil, err
+	}
+	return backend, nil
+}
+
 // init caches all LLMBackend and LLMRoute objects in the cluster after the controller gets the leader election,
 // and starts a goroutine to handle the events from the controllers.
 func (c *configSink) init(ctx context.Context) error {
-	var llmBackends aigv1a1.LLMBackendList
-	if err := c.client.List(ctx, &llmBackends); err != nil {
-		return fmt.Errorf("failed to list LLMBackends: %w", err)
-	}
-
-	for i := range llmBackends.Items {
-		llmBackend := &llmBackends.Items[i]
-		c.backends[fmt.Sprintf("%s.%s", llmBackend.Name, llmBackend.Namespace)] = llmBackend
-	}
-
-	var llmRoutes aigv1a1.LLMRouteList
-	if err := c.client.List(ctx, &llmRoutes); err != nil {
-		return fmt.Errorf("failed to list LLMRoutes: %w", err)
-	}
-
-	for i := range llmRoutes.Items {
-		llmRoute := &llmRoutes.Items[i]
-		llmRouteKey := fmt.Sprintf("%s.%s", llmRoute.Name, llmRoute.Namespace)
-		c.llmRoutes[llmRouteKey] = llmRoute
-
-		for _, rule := range llmRoute.Spec.Rules {
-			for _, backend := range rule.BackendRefs {
-				backendKey := fmt.Sprintf("%s.%s", backend.Name, llmRoute.Namespace)
-				if _, ok := c.backendsToReferencingRoutes[backendKey]; !ok {
-					c.backendsToReferencingRoutes[backendKey] = make(map[*aigv1a1.LLMRoute]struct{})
-				}
-				c.backendsToReferencingRoutes[backendKey][llmRoute] = struct{}{}
-			}
-		}
-	}
-
 	go func() {
 		for {
 			select {
@@ -127,20 +80,15 @@ func (c *configSink) handleEvent(event ConfigSinkEvent) {
 	switch e := event.(type) {
 	case *aigv1a1.LLMBackend:
 		c.syncLLMBackend(e)
-	case ConfigSinkEventLLMBackendDeleted:
-		c.deleteLLMBackend(e)
 	case *aigv1a1.LLMRoute:
 		c.syncLLMRoute(e)
-	case ConfigSinkEventLLMRouteDeleted:
-		c.deleteLLMRoute(e)
 	default:
 		panic(fmt.Sprintf("unexpected event type: %T", e))
 	}
 }
 
 func (c *configSink) syncLLMRoute(llmRoute *aigv1a1.LLMRoute) {
 	// Check if the HTTPRoute exists.
-	key := fmt.Sprintf("%s.%s", llmRoute.Name, llmRoute.Namespace)
 	var httpRoute gwapiv1.HTTPRoute
 	err := c.client.Get(context.Background(), client.ObjectKey{Name: llmRoute.Name, Namespace: llmRoute.Namespace}, &httpRoute)
 	existingRoute := err == nil
@@ -183,36 +131,19 @@ func (c *configSink) syncLLMRoute(llmRoute *aigv1a1.LLMRoute) {
 		c.logger.Error(err, "failed to update extproc configmap", "namespace", llmRoute.Namespace, "name", llmRoute.Name)
 		return
 	}
-
-	// Update the referencing map.
-	for _, rule := range llmRoute.Spec.Rules {
-		for _, backend := range rule.BackendRefs {
-			key := fmt.Sprintf("%s.%s", backend.Name, llmRoute.Namespace)
-			if _, ok := c.backendsToReferencingRoutes[key]; !ok {
-				c.backendsToReferencingRoutes[key] = make(map[*aigv1a1.LLMRoute]struct{})
-			}
-			c.backendsToReferencingRoutes[key][llmRoute] = struct{}{}
-		}
-	}
-	c.llmRoutes[key] = llmRoute
 }
 
 func (c *configSink) syncLLMBackend(llmBackend *aigv1a1.LLMBackend) {
 	key := fmt.Sprintf("%s.%s", llmBackend.Name, llmBackend.Namespace)
-	c.backends[key] = llmBackend
-	for referencedLLMRoute := range c.backendsToReferencingRoutes[key] {
-		c.syncLLMRoute(referencedLLMRoute)
+	var llmRoutes aigv1a1.LLMRouteList
+	err := c.client.List(context.Background(), &llmRoutes, client.MatchingFields{k8sClientIndexBackendToReferencingLLMRoute: key})
+	if err != nil {
+		c.logger.Error(err, "failed to list LLMRoutes", "backend", key)
+		return
+	}
+	for _, llmRoute := range llmRoutes.Items {
+		c.syncLLMRoute(&llmRoute)
 	}
-}
-
-func (c *configSink) deleteLLMRoute(event ConfigSinkEventLLMRouteDeleted) {
-	delete(c.llmRoutes, event.String())
-}
-
-func (c *configSink) deleteLLMBackend(event ConfigSinkEventLLMBackendDeleted) {
-	key := event.String()
-	delete(c.backends, key)
-	delete(c.backendsToReferencingRoutes, key)
 }
 
 // updateExtProcConfigMap updates the external process configmap with the new LLMRoute.
@@ -237,10 +168,9 @@ func (c *configSink) updateExtProcConfigMap(llmRoute *aigv1a1.LLMRoute) error {
 			key := fmt.Sprintf("%s.%s", backend.Name, llmRoute.Namespace)
 			ec.Rules[i].Backends[j].Name = key
 			ec.Rules[i].Backends[j].Weight = backend.Weight
-			backendObj, ok := c.backends[key]
-			if !ok {
-				err = fmt.Errorf("backend %s not found", key)
-				return err
+			backendObj, err := c.backend(llmRoute.Namespace, backend.Name)
+			if err != nil {
+				return fmt.Errorf("failed to get LLMBackend %s: %w", key, err)
 			} else {
 				ec.Rules[i].Backends[j].OutputSchema.Schema = filterconfig.APISchema(backendObj.Spec.APISchema.Schema)
 				ec.Rules[i].Backends[j].OutputSchema.Version = backendObj.Spec.APISchema.Version
@@ -278,8 +208,8 @@ func (c *configSink) newHTTPRoute(dst *gwapiv1.HTTPRoute, llmRoute *aigv1a1.LLMR
 				continue
 			}
 			dedup[key] = struct{}{}
-			backend, ok := c.backends[key]
-			if !ok {
+			backend, err := c.backend(llmRoute.Namespace, br.Name)
+			if err != nil {
 				return fmt.Errorf("LLMBackend %s not found", key)
 			}
 			backends = append(backends, backend)