Allow FQDN for ExternalName Service

internal/ingress/controller/endpoints.go

@@ -21,6 +21,7 @@ import (
 	"net"
 	"reflect"
 	"strconv"
+	"strings"
 
 	"k8s.io/apimachinery/pkg/util/validation"
 	"k8s.io/klog/v2"
@@ -53,7 +54,8 @@ func getEndpoints(s *corev1.Service, port *corev1.ServicePort, proto corev1.Prot
 		targetPort := port.TargetPort.IntValue()
 		// if the externalName is not an IP address we need to validate is a valid FQDN
 		if net.ParseIP(s.Spec.ExternalName) == nil {
-			if errs := validation.IsDNS1123Subdomain(s.Spec.ExternalName); len(errs) > 0 {
+			externalName := strings.TrimSuffix(s.Spec.ExternalName, ".")
+			if errs := validation.IsDNS1123Subdomain(externalName); len(errs) > 0 {
 				klog.Errorf("Invalid DNS name %s: %v", s.Spec.ExternalName, errs)
 				return upsServers
 			}

internal/ingress/controller/endpoints_test.go

@@ -107,6 +107,35 @@ func TestGetEndpoints(t *testing.T) {
 				},
 			},
 		},
+		{
+			"a service type ServiceTypeExternalName with an trailing dot ExternalName value should return one endpoints",
+			&corev1.Service{
+				Spec: corev1.ServiceSpec{
+					Type:         corev1.ServiceTypeExternalName,
+					ExternalName: "www.google.com.",
+					Ports: []corev1.ServicePort{
+						{
+							Name:       "default",
+							TargetPort: intstr.FromInt(80),
+						},
+					},
+				},
+			},
+			&corev1.ServicePort{
+				Name:       "default",
+				TargetPort: intstr.FromInt(80),
+			},
+			corev1.ProtocolTCP,
+			func(string) (*corev1.Endpoints, error) {
+				return &corev1.Endpoints{}, nil
+			},
+			[]ingress.Endpoint{
+				{
+					Address: "www.google.com",
+					Port:    "443",
+				},
+			},
+		},
 		{
 			"a service type ServiceTypeExternalName with an invalid ExternalName value should no return endpoints",
 			&corev1.Service{