From 57ae9a80d5ccba29c8f566a8be4c27512727d9ac Mon Sep 17 00:00:00 2001
From: Andy Kipp <kipp.andrew@gmail.com>
Date: Wed, 27 Mar 2019 13:48:04 -0300
Subject: [PATCH] Support external name service on global default backend

---
 provider/kubernetes/kubernetes.go      | 77 +++++++++++++++++---------
 provider/kubernetes/kubernetes_test.go | 53 ++++++++++++++++++
 2 files changed, 103 insertions(+), 27 deletions(-)

diff --git a/provider/kubernetes/kubernetes.go b/provider/kubernetes/kubernetes.go
index 610f6bc70..46cd673ac 100644
--- a/provider/kubernetes/kubernetes.go
+++ b/provider/kubernetes/kubernetes.go
@@ -503,39 +503,62 @@ func (p *Provider) addGlobalBackend(cl Client, i *extensionsv1beta1.Ingress, tem
 	templateObjects.Backends[defaultBackendName].ResponseForwarding = getResponseForwarding(service)
 
 	for _, port := range service.Spec.Ports {
-		endpoints, exists, err := cl.GetEndpoints(service.Namespace, service.Name)
-		if err != nil {
-			return fmt.Errorf("error retrieving endpoint information from k8s API %s/%s: %v", service.Namespace, service.Name, err)
-		}
-		if !exists {
-			return fmt.Errorf("endpoints not found for %s/%s", service.Namespace, service.Name)
-		}
-		if len(endpoints.Subsets) == 0 {
-			return fmt.Errorf("endpoints not available for %s/%s", service.Namespace, service.Name)
-		}
 
-		for _, subset := range endpoints.Subsets {
-			endpointPort := endpointPortNumber(port, subset.Ports)
-			if endpointPort == 0 {
-				// endpoint port does not match service.
-				continue
-			}
+		// We have to treat external-name service differently here b/c it doesn't have any endpoints
+		if service.Spec.Type == corev1.ServiceTypeExternalName {
 
 			protocol := "http"
-			for _, address := range subset.Addresses {
-				if endpointPort == 443 || strings.HasPrefix(i.Spec.Backend.ServicePort.String(), "https") {
-					protocol = "https"
+			if port.Port == 443 || strings.HasPrefix(port.Name, "https") {
+				protocol = "https"
+			}
+
+			url := protocol + "://" + service.Spec.ExternalName
+			if port.Port != 443 && port.Port != 80 {
+				url = fmt.Sprintf("%s:%d", url, port.Port)
+			}
+
+			templateObjects.Backends[defaultBackendName].Servers[url] = types.Server{
+				URL:    url,
+				Weight: label.DefaultWeight,
+			}
+
+		} else {
+
+			endpoints, exists, err := cl.GetEndpoints(service.Namespace, service.Name)
+			if err != nil {
+				return fmt.Errorf("error retrieving endpoint information from k8s API %s/%s: %v", service.Namespace, service.Name, err)
+			}
+			if !exists {
+				return fmt.Errorf("endpoints not found for %s/%s", service.Namespace, service.Name)
+			}
+			if len(endpoints.Subsets) == 0 {
+				return fmt.Errorf("endpoints not available for %s/%s", service.Namespace, service.Name)
+			}
+
+			for _, subset := range endpoints.Subsets {
+
+				endpointPort := endpointPortNumber(port, subset.Ports)
+				if endpointPort == 0 {
+					// endpoint port does not match service.
+					continue
 				}
 
-				url := fmt.Sprintf("%s://%s", protocol, net.JoinHostPort(address.IP, strconv.FormatInt(int64(endpointPort), 10)))
-				name := url
-				if address.TargetRef != nil && address.TargetRef.Name != "" {
-					name = address.TargetRef.Name
-				}
+				protocol := "http"
+				for _, address := range subset.Addresses {
+					if endpointPort == 443 || strings.HasPrefix(i.Spec.Backend.ServicePort.String(), "https") {
+						protocol = "https"
+					}
 
-				templateObjects.Backends[defaultBackendName].Servers[name] = types.Server{
-					URL:    url,
-					Weight: label.DefaultWeight,
+					url := fmt.Sprintf("%s://%s", protocol, net.JoinHostPort(address.IP, strconv.FormatInt(int64(endpointPort), 10)))
+					name := url
+					if address.TargetRef != nil && address.TargetRef.Name != "" {
+						name = address.TargetRef.Name
+					}
+
+					templateObjects.Backends[defaultBackendName].Servers[name] = types.Server{
+						URL:    url,
+						Weight: label.DefaultWeight,
+					}
 				}
 			}
 		}
diff --git a/provider/kubernetes/kubernetes_test.go b/provider/kubernetes/kubernetes_test.go
index fe301d24e..dae718278 100644
--- a/provider/kubernetes/kubernetes_test.go
+++ b/provider/kubernetes/kubernetes_test.go
@@ -284,6 +284,59 @@ func TestLoadIngresses(t *testing.T) {
 	assert.Equal(t, expected, actual)
 }
 
+func TestLoadGlobalIngressWithExternalName(t *testing.T) {
+	ingresses := []*extensionsv1beta1.Ingress{
+		buildIngress(
+			iNamespace("testing"),
+			iSpecBackends(iSpecBackend(iIngressBackend("service1", intstr.FromInt(80)))),
+		),
+	}
+
+	services := []*corev1.Service{
+		buildService(
+			sName("service1"),
+			sNamespace("testing"),
+			sUID("1"),
+			sSpec(
+				sType("ExternalName"),
+				sExternalName("some-external-name"),
+				sPorts(sPort(80, ""))),
+		),
+	}
+
+	watchChan := make(chan interface{})
+	client := clientMock{
+		ingresses: ingresses,
+		services:  services,
+		watchChan: watchChan,
+	}
+	provider := Provider{}
+
+	actual, err := provider.loadIngresses(client)
+	require.NoError(t, err, "error loading ingresses")
+
+	expected := buildConfiguration(
+		backends(
+			backend("global-default-backend",
+				lbMethod("wrr"),
+				servers(
+					server("http://some-external-name", weight(1)),
+				),
+			),
+		),
+		frontends(
+			frontend("global-default-backend",
+				frontendName("global-default-frontend"),
+				passHostHeader(),
+				routes(
+					route("/", "PathPrefix:/"),
+				),
+			),
+		),
+	)
+	assert.Equal(t, expected, actual)
+}
+
 func TestLoadGlobalIngressWithPortNumbers(t *testing.T) {
 	ingresses := []*extensionsv1beta1.Ingress{
 		buildIngress(