NE-1954: Implement GatewayAPIController feature gate

Skipped starting the gatewayclass and service dns controllers
when the GatewayAPIController feature gate is disabled.

Author: alebedev87

pkg/operator/controller/gatewayapi/controller.go

@@ -76,6 +76,8 @@ func New(mgr manager.Manager, config Config) (controller.Controller, error) {
 type Config struct {
 	// GatewayAPIEnabled indicates that the "GatewayAPI" featuregate is enabled.
 	GatewayAPIEnabled bool
+	// GatewayAPIControllerEnabled indicates that the "GatewayAPIController" featuregate is enabled.
+	GatewayAPIControllerEnabled bool
 
 	// DependentControllers is a list of controllers that watch Gateway API
 	// resources.  The gatewayapi controller starts these controllers once
@@ -105,6 +107,10 @@ func (r *reconciler) Reconcile(ctx context.Context, request reconcile.Request) (
 		return reconcile.Result{}, err
 	}
 
+	if !r.config.GatewayAPIControllerEnabled {
+		return reconcile.Result{}, nil
+	}
+
 	r.startControllers.Do(func() {
 		for i := range r.config.DependentControllers {
 			c := &r.config.DependentControllers[i]

pkg/operator/controller/gatewayapi/controller_test.go

@@ -35,13 +35,14 @@ func Test_Reconcile(t *testing.T) {
 		}
 	}
 	tests := []struct {
-		name              string
-		gatewayAPIEnabled bool
-		existingObjects   []runtime.Object
-		expectCreate      []client.Object
-		expectUpdate      []client.Object
-		expectDelete      []client.Object
-		expectStartCtrl   bool
+		name                        string
+		gatewayAPIEnabled           bool
+		gatewayAPIControllerEnabled bool
+		existingObjects             []runtime.Object
+		expectCreate                []client.Object
+		expectUpdate                []client.Object
+		expectDelete                []client.Object
+		expectStartCtrl             bool
 	}{
 		{
 			name:              "gateway API disabled",
@@ -52,8 +53,9 @@ func Test_Reconcile(t *testing.T) {
 			expectStartCtrl:   false,
 		},
 		{
-			name:              "gateway API enabled",
-			gatewayAPIEnabled: true,
+			name:                        "gateway API enabled",
+			gatewayAPIEnabled:           true,
+			gatewayAPIControllerEnabled: true,
 			expectCreate: []client.Object{
 				crd("gatewayclasses.gateway.networking.k8s.io"),
 				crd("gateways.gateway.networking.k8s.io"),
@@ -64,6 +66,20 @@ func Test_Reconcile(t *testing.T) {
 			expectDelete:    []client.Object{},
 			expectStartCtrl: true,
 		},
+		{
+			name:                        "gateway API enabled, gateway API controller disabled",
+			gatewayAPIEnabled:           true,
+			gatewayAPIControllerEnabled: false,
+			expectCreate: []client.Object{
+				crd("gatewayclasses.gateway.networking.k8s.io"),
+				crd("gateways.gateway.networking.k8s.io"),
+				crd("httproutes.gateway.networking.k8s.io"),
+				crd("referencegrants.gateway.networking.k8s.io"),
+			},
+			expectUpdate:    []client.Object{},
+			expectDelete:    []client.Object{},
+			expectStartCtrl: false,
+		},
 	}
 
 	scheme := runtime.NewScheme()
@@ -81,8 +97,9 @@ func Test_Reconcile(t *testing.T) {
 			reconciler := &reconciler{
 				client: cl,
 				config: Config{
-					GatewayAPIEnabled:    tc.gatewayAPIEnabled,
-					DependentControllers: []controller.Controller{ctrl},
+					GatewayAPIEnabled:           tc.gatewayAPIEnabled,
+					GatewayAPIControllerEnabled: tc.gatewayAPIControllerEnabled,
+					DependentControllers:        []controller.Controller{ctrl},
 				},
 			}
 			req := reconcile.Request{
@@ -131,8 +148,9 @@ func TestReconcileOnlyStartsControllerOnce(t *testing.T) {
 	reconciler := &reconciler{
 		client: cl,
 		config: Config{
-			GatewayAPIEnabled:    true,
-			DependentControllers: []controller.Controller{ctrl},
+			GatewayAPIEnabled:           true,
+			GatewayAPIControllerEnabled: true,
+			DependentControllers:        []controller.Controller{ctrl},
 		},
 	}
 	req := reconcile.Request{NamespacedName: types.NamespacedName{Name: "cluster"}}

pkg/operator/operator.go

@@ -132,6 +132,7 @@ func New(config operatorconfig.Config, kubeConfig *rest.Config) (*Operator, erro
 	azureWorkloadIdentityEnabled := featureGates.Enabled(features.FeatureGateAzureWorkloadIdentity)
 	sharedVPCEnabled := featureGates.Enabled(features.FeatureGatePrivateHostedZoneAWS)
 	gatewayAPIEnabled := featureGates.Enabled(features.FeatureGateGatewayAPI)
+	gatewayAPIControllerEnabled := featureGates.Enabled(features.FeatureGateGatewayAPIController)
 	routeExternalCertificateEnabled := featureGates.Enabled(features.FeatureGateRouteExternalCertificate)
 	ingressControllerLBSubnetsAWSEnabled := featureGates.Enabled(features.FeatureGateIngressControllerLBSubnetsAWS)
 	ingressControllerEIPAllocationsAWSEnabled := featureGates.Enabled(features.FeatureGateSetEIPForNLBIngressController)
@@ -311,7 +312,8 @@ func New(config operatorconfig.Config, kubeConfig *rest.Config) (*Operator, erro
 
 	// Set up the gatewayapi controller.
 	if _, err := gatewayapicontroller.New(mgr, gatewayapicontroller.Config{
-		GatewayAPIEnabled: gatewayAPIEnabled,
+		GatewayAPIEnabled:           gatewayAPIEnabled,
+		GatewayAPIControllerEnabled: gatewayAPIControllerEnabled,
 		DependentControllers: []controller.Controller{
 			gatewayClassController,
 			gatewayServiceDNSController,

test/e2e/gateway_api_test.go

@@ -60,6 +60,11 @@ func TestGatewayAPI(t *testing.T) {
 		t.Skip("Gateway API not enabled, skipping TestGatewayAPI")
 	}
 
+	gatewayAPIControllerEnabled, err := isFeatureGateEnabled(features.FeatureGateGatewayAPIController)
+	if err != nil {
+		t.Fatalf("error checking controller feature gate enabled status: %v", err)
+	}
+
 	// Defer the cleanup of the test gateway.
 	t.Cleanup(func() {
 		testGateway := gatewayapiv1.Gateway{ObjectMeta: metav1.ObjectMeta{Name: testGatewayName, Namespace: operatorcontroller.DefaultOperandNamespace}}
@@ -73,8 +78,12 @@ func TestGatewayAPI(t *testing.T) {
 	})
 
 	t.Run("testGatewayAPIResources", testGatewayAPIResources)
-	t.Run("testGatewayAPIObjects", testGatewayAPIObjects)
-	t.Run("testGatewayAPIIstioInstallation", testGatewayAPIIstioInstallation)
+	if gatewayAPIControllerEnabled {
+		t.Run("testGatewayAPIObjects", testGatewayAPIObjects)
+		t.Run("testGatewayAPIIstioInstallation", testGatewayAPIIstioInstallation)
+	} else {
+		t.Log("Gateway API Controller not enabled, skipping testGatewayAPIObjects and testGatewayAPIIstioInstallation")
+	}
 }
 
 // testGatewayAPIResources tests that Gateway API Custom Resource Definitions are available.