Migrate to EndpointSlices API

pkg/provider/kubernetes/gateway/httproute.go

@@ -370,6 +370,10 @@ func (p *Provider) loadHTTPRouteFilterExtensionRef(namespace string, extensionRe
 }
 
 func (p *Provider) loadHTTPServers(namespace string, backendRef gatev1.HTTPBackendRef) (*dynamic.ServersLoadBalancer, error) {
+	if backendRef.Port == nil {
+		return nil, errors.New("port is required for Kubernetes Service reference")
+	}
+
 	service, exists, err := p.client.GetService(namespace, string(backendRef.Name))
 	if err != nil {
 		return nil, fmt.Errorf("getting service: %w", err)
@@ -378,56 +382,58 @@ func (p *Provider) loadHTTPServers(namespace string, backendRef gatev1.HTTPBacke
 		return nil, errors.New("service not found")
 	}
 
-	var portSpec corev1.ServicePort
-	var match bool
-
+	var svcPort *corev1.ServicePort
 	for _, p := range service.Spec.Ports {
-		if backendRef.Port == nil || p.Port == int32(*backendRef.Port) {
-			portSpec = p
-			match = true
+		if p.Port == int32(*backendRef.Port) {
+			svcPort = &p
 			break
 		}
 	}
-	if !match {
-		return nil, errors.New("service port not found")
+	if svcPort == nil {
+		return nil, fmt.Errorf("service port %d not found", *backendRef.Port)
 	}
 
-	endpoints, endpointsExists, err := p.client.GetEndpoints(namespace, string(backendRef.Name))
+	endpointSlices, err := p.client.ListEndpointSlicesForService(namespace, string(backendRef.Name))
 	if err != nil {
-		return nil, fmt.Errorf("getting endpoints: %w", err)
+		return nil, fmt.Errorf("getting endpointslices: %w", err)
 	}
-	if !endpointsExists {
-		return nil, errors.New("endpoints not found")
-	}
-
-	if len(endpoints.Subsets) == 0 {
-		return nil, errors.New("subset not found")
+	if len(endpointSlices) == 0 {
+		return nil, errors.New("endpointslices not found")
 	}
 
 	lb := &dynamic.ServersLoadBalancer{}
 	lb.SetDefaults()
 
-	var port int32
-	var portStr string
-	for _, subset := range endpoints.Subsets {
-		for _, p := range subset.Ports {
-			if portSpec.Name == p.Name {
-				port = p.Port
+	protocol := getProtocol(*svcPort)
+
+	addresses := map[string]struct{}{}
+	for _, endpointSlice := range endpointSlices {
+		var port int32
+		for _, p := range endpointSlice.Ports {
+			if svcPort.Name == *p.Name {
+				port = *p.Port
 				break
 			}
 		}
-
 		if port == 0 {
-			return nil, errors.New("cannot define a port")
+			continue
 		}
 
-		protocol := getProtocol(portSpec)
+		for _, endpoint := range endpointSlice.Endpoints {
+			if endpoint.Conditions.Ready == nil || !*endpoint.Conditions.Ready {
+				continue
+			}
 
-		portStr = strconv.FormatInt(int64(port), 10)
-		for _, addr := range subset.Addresses {
-			lb.Servers = append(lb.Servers, dynamic.Server{
-				URL: fmt.Sprintf("%s://%s", protocol, net.JoinHostPort(addr.IP, portStr)),
-			})
+			for _, address := range endpoint.Addresses {
+				if _, ok := addresses[address]; ok {
+					continue
+				}
+
+				addresses[address] = struct{}{}
+				lb.Servers = append(lb.Servers, dynamic.Server{
+					URL: fmt.Sprintf("%s://%s", protocol, net.JoinHostPort(address, strconv.Itoa(int(port)))),
+				})
+			}
 		}
 	}