Merge pull request #6617 from nic-6443/external-name-fqdn

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{

test/e2e/servicebackend/service_externalname.go

@@ -218,6 +218,37 @@ var _ = framework.IngressNginxDescribe("[Service] Type ExternalName", func() {
 			Status(http.StatusOK)
 	})
 
+	ginkgo.It("should return 200 for service type=ExternalName using FQDN with trailing dot", func() {
+		host := "echo"
+
+		svc := &core.Service{
+			ObjectMeta: metav1.ObjectMeta{
+				Name:      framework.HTTPBinService,
+				Namespace: f.Namespace,
+			},
+			Spec: corev1.ServiceSpec{
+				ExternalName: "httpbin.org.",
+				Type:         corev1.ServiceTypeExternalName,
+			},
+		}
+
+		f.EnsureService(svc)
+
+		ing := framework.NewSingleIngress(host, "/", host, f.Namespace, framework.HTTPBinService, 80, nil)
+		f.EnsureIngress(ing)
+
+		f.WaitForNginxServer(host,
+			func(server string) bool {
+				return strings.Contains(server, "proxy_pass http://upstream_balancer;")
+			})
+
+		f.HTTPTestClient().
+			GET("/get").
+			WithHeader("Host", host).
+			Expect().
+			Status(http.StatusOK)
+	})
+
 	ginkgo.It("should update the external name after a service update", func() {
 		host := "echo"