fix: decouple gateway status updates from the reconciler

internal/message/types.go

@@ -75,12 +75,13 @@ func (p *ProviderResources) Close() {
 
 // GatewayAPIStatuses contains gateway API resources statuses
 type GatewayAPIStatuses struct {
-	GatewayStatuses   watchable.Map[types.NamespacedName, *gwapiv1.GatewayStatus]
-	HTTPRouteStatuses watchable.Map[types.NamespacedName, *gwapiv1.HTTPRouteStatus]
-	GRPCRouteStatuses watchable.Map[types.NamespacedName, *gwapiv1.GRPCRouteStatus]
-	TLSRouteStatuses  watchable.Map[types.NamespacedName, *gwapiv1a2.TLSRouteStatus]
-	TCPRouteStatuses  watchable.Map[types.NamespacedName, *gwapiv1a2.TCPRouteStatus]
-	UDPRouteStatuses  watchable.Map[types.NamespacedName, *gwapiv1a2.UDPRouteStatus]
+	GatewayClassStatuses watchable.Map[types.NamespacedName, *gwapiv1.GatewayClassStatus]
+	GatewayStatuses      watchable.Map[types.NamespacedName, *gwapiv1.GatewayStatus]
+	HTTPRouteStatuses    watchable.Map[types.NamespacedName, *gwapiv1.HTTPRouteStatus]
+	GRPCRouteStatuses    watchable.Map[types.NamespacedName, *gwapiv1.GRPCRouteStatus]
+	TLSRouteStatuses     watchable.Map[types.NamespacedName, *gwapiv1a2.TLSRouteStatus]
+	TCPRouteStatuses     watchable.Map[types.NamespacedName, *gwapiv1a2.TCPRouteStatus]
+	UDPRouteStatuses     watchable.Map[types.NamespacedName, *gwapiv1a2.UDPRouteStatus]
 }
 
 func (s *GatewayAPIStatuses) Close() {

internal/provider/kubernetes/controller.go

@@ -129,13 +129,25 @@
 	}
 	r.log.Info("created gatewayapi controller")
 
-	// Subscribe to status updates
-	r.subscribeAndUpdateStatus(ctx, cfg.EnvoyGateway.EnvoyGatewaySpec.ExtensionManager != nil)
-
 	// Watch resources
 	if err := r.watchResources(ctx, mgr, c); err != nil {
 		return fmt.Errorf("error watching resources: %w", err)
 	}
+
+	// When leader election is enabled, only subscribe to status updates upon acquiring leadership.
+	if cfg.EnvoyGateway.Provider.Type == egv1a1.ProviderTypeKubernetes &&
+		!ptr.Deref(cfg.EnvoyGateway.Provider.Kubernetes.LeaderElection.Disable, false) {
+		go func() {
+			select {
+			case <-ctx.Done():
+				return
+			case <-mgr.Elected():
+				r.subscribeAndUpdateStatus(ctx, cfg.EnvoyGateway.EnvoyGatewaySpec.ExtensionManager != nil)
+			}
+		}()
+	} else {
+		r.subscribeAndUpdateStatus(ctx, cfg.EnvoyGateway.EnvoyGatewaySpec.ExtensionManager != nil)
+	}
 	return nil
 }
 
@@ -199,9 +211,12 @@
 		if managedGC.Spec.ParametersRef != nil && managedGC.DeletionTimestamp == nil {
 			if err := r.processGatewayClassParamsRef(ctx, managedGC, resourceMappings, gwcResource); err != nil {
 				msg := fmt.Sprintf("%s: %v", status.MsgGatewayClassInvalidParams, err)
-				if err := r.updateStatusForGatewayClass(ctx, managedGC, false, string(gwapiv1.GatewayClassReasonInvalidParameters), msg); err != nil {
-					r.log.Error(err, "unable to update GatewayClass status")
-				}
+				gc := status.SetGatewayClassAccepted(
+					managedGC.DeepCopy(),
+					false,
+					string(gwapiv1.GatewayClassReasonInvalidParameters),
+					msg)
+				r.resources.GatewayClassStatuses.Store(utils.NamespacedName(gc), &gc.Status)
 				r.log.Error(err, "failed to process parametersRef for gatewayclass", "name", managedGC.Name)
 				return reconcile.Result{}, err
 			}
@@ -293,11 +308,12 @@
 
 		// process envoy gateway secret refs
 		r.processEnvoyProxySecretRef(ctx, gwcResource)
-
-		if err := r.updateStatusForGatewayClass(ctx, managedGC, true, string(gwapiv1.GatewayClassReasonAccepted), status.MsgValidGatewayClass); err != nil {
-			r.log.Error(err, "unable to update GatewayClass status")
-			return reconcile.Result{}, err
-		}
+		gc := status.SetGatewayClassAccepted(
+			managedGC.DeepCopy(),
+			true,
+			string(gwapiv1.GatewayClassReasonAccepted),
+			status.MsgValidGatewayClass)
+		r.resources.GatewayClassStatuses.Store(utils.NamespacedName(gc), &gc.Status)
 
 		if len(gwcResource.Gateways) == 0 {
 			r.log.Info("No gateways found for accepted gatewayclass")

internal/provider/kubernetes/predicates.go

@@ -294,7 +294,7 @@
 	// Check if the Service belongs to a Gateway, if so, update the Gateway status.
 	gtw := r.findOwningGateway(ctx, labels)
 	if gtw != nil {
-		r.updateStatusForGateway(ctx, gtw)
+		r.updateGatewayStatus(gtw)
 		return false
 	}
 
@@ -528,7 +528,7 @@
 		// Check if the obj belongs to a Gateway, if so, update the Gateway status.
 		gtw := r.findOwningGateway(ctx, labels)
 		if gtw != nil {
-			r.updateStatusForGateway(ctx, gtw)
+			r.updateGatewayStatus(gtw)
 			return false
 		}
 	}
@@ -636,12 +636,32 @@
 	}
 
 	for _, gateway := range gateways.Items {
-		r.updateStatusForGateway(ctx, &gateway)
+		r.updateGatewayStatus(&gateway)
 	}
 
 	return nil
 }
 
+// updateGatewayStatus triggers a status update for the Gateway.
+func (r *gatewayAPIReconciler) updateGatewayStatus(gateway *gwapiv1.Gateway) {
+	gwName := utils.NamespacedName(gateway)
+	status := &gateway.Status
+	// Use the existing status if it exists to avoid losing the status calculated by the Gateway API translator.
+	if existing, ok := r.resources.GatewayStatuses.Load(gwName); ok {
+		status = existing
+	}
+
+	// Since the status does not reflect the actual changed status, we need to delete it first
+	// to prevent it from being considered unchanged. This ensures that subscribers receive the update event.
+	r.resources.GatewayStatuses.Delete(gwName)
+	// The status that is stored in the GatewayStatuses GatewayStatuses is solely used to trigger the status updater
+	// and does not reflect the real changed status.
+	//
+	// The status updater will check the Envoy Proxy service to get the addresses of the Gateway,
+	// and check the Envoy Proxy Deployment/DaemonSet to get the status of the Gateway workload.
+	r.resources.GatewayStatuses.Store(gwName, status)
+}
+
 func (r *gatewayAPIReconciler) handleNode(obj client.Object) bool {
 	ctx := context.Background()
 	node, ok := obj.(*corev1.Node)

internal/provider/kubernetes/predicates_test.go

@@ -26,6 +26,7 @@ import (
 	"github.com/envoyproxy/gateway/internal/gatewayapi/resource"
 	"github.com/envoyproxy/gateway/internal/infrastructure/kubernetes/proxy"
 	"github.com/envoyproxy/gateway/internal/logging"
+	"github.com/envoyproxy/gateway/internal/message"
 	"github.com/envoyproxy/gateway/internal/provider/kubernetes/test"
 )
 
@@ -854,6 +855,7 @@ func TestValidateServiceForReconcile(t *testing.T) {
 		classController:    egv1a1.GatewayControllerName,
 		log:                logger,
 		mergeGateways:      sets.New[string]("test-mg"),
+		resources:          &message.ProviderResources{},
 		grpcRouteCRDExists: true,
 		tcpRouteCRDExists:  true,
 		udpRouteCRDExists:  true,
@@ -972,6 +974,7 @@ func TestValidateObjectForReconcile(t *testing.T) {
 		classController: egv1a1.GatewayControllerName,
 		log:             logger,
 		mergeGateways:   sets.New[string]("test-mg"),
+		resources:       &message.ProviderResources{},
 	}
 
 	for _, tc := range testCases {

internal/provider/kubernetes/status.go

@@ -10,7 +10,6 @@
 	"fmt"
 	"reflect"
 
-	kerrors "k8s.io/apimachinery/pkg/api/errors"
 	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
 	"k8s.io/apimachinery/pkg/types"
 	"sigs.k8s.io/controller-runtime/pkg/client"
@@ -28,6 +27,35 @@
 // subscribeAndUpdateStatus subscribes to gateway API object status updates and
 // writes it into the Kubernetes API Server.
 func (r *gatewayAPIReconciler) subscribeAndUpdateStatus(ctx context.Context, extensionManagerEnabled bool) {
+	// GatewayClass object status updater
+	go func() {
+		message.HandleSubscription(
+			message.Metadata{Runner: string(egv1a1.LogComponentProviderRunner), Message: "gatewayclass-status"},
+			r.resources.GatewayClassStatuses.Subscribe(ctx),
+			func(update message.Update[types.NamespacedName, *gwapiv1.GatewayClassStatus], errChan chan error) {
+				// skip delete updates.
+				if update.Delete {
+					return
+				}
+
+				r.statusUpdater.Send(Update{
+					NamespacedName: update.Key,
+					Resource:       new(gwapiv1.GatewayClass),
+					Mutator: MutatorFunc(func(obj client.Object) client.Object {
+						gc, ok := obj.(*gwapiv1.GatewayClass)
+						if !ok {
+							panic(fmt.Sprintf("unsupported object type %T", obj))
+						}
+						gcCopy := gc.DeepCopy()
+						gcCopy.Status = *update.Value
+						return gcCopy
+					}),
+				})
+			},
+		)
+		r.log.Info("gatewayclass status subscriber shutting down")
+	}()
+
 	// Gateway object status updater
 	go func() {
 		message.HandleSubscription(
@@ -564,34 +592,3 @@
 		}),
 	})
 }
-
-func (r *gatewayAPIReconciler) updateStatusForGatewayClass(
-	ctx context.Context,
-	gc *gwapiv1.GatewayClass,
-	accepted bool,
-	reason,
-	msg string,
-) error {
-	if r.statusUpdater != nil {
-		r.statusUpdater.Send(Update{
-			NamespacedName: types.NamespacedName{Name: gc.Name},
-			Resource:       &gwapiv1.GatewayClass{},
-			Mutator: MutatorFunc(func(obj client.Object) client.Object {
-				gc, ok := obj.(*gwapiv1.GatewayClass)
-				if !ok {
-					panic(fmt.Sprintf("unsupported object type %T", obj))
-				}
-
-				return status.SetGatewayClassAccepted(gc.DeepCopy(), accepted, reason, msg)
-			}),
-		})
-	} else {
-		// this branch makes testing easier by not going through the status.Updater.
-		duplicate := status.SetGatewayClassAccepted(gc.DeepCopy(), accepted, reason, msg)
-
-		if err := r.client.Status().Update(ctx, duplicate); err != nil && !kerrors.IsNotFound(err) {
-			return fmt.Errorf("error updating status of gatewayclass %s: %w", duplicate.Name, err)
-		}
-	}
-	return nil
-}