Allow empty path with App-root annotation

old/provider/kubernetes/kubernetes.go

@@ -939,7 +939,7 @@ func loadAuthTLSSecret(namespace, secretName string, k8sClient Client) (string,
 func getFrontendRedirect(i *extensionsv1beta1.Ingress, baseName, path string) *types.Redirect {
 	permanent := getBoolValue(i.Annotations, annotationKubernetesRedirectPermanent, false)
 
-	if appRoot := getStringValue(i.Annotations, annotationKubernetesAppRoot, ""); appRoot != "" && path == "/" {
+	if appRoot := getStringValue(i.Annotations, annotationKubernetesAppRoot, ""); appRoot != "" && (path == "/" || path == "") {
 		return &types.Redirect{
 			Regex:       fmt.Sprintf("%s$", baseName),
 			Replacement: fmt.Sprintf("%s/%s", strings.TrimRight(baseName, "/"), strings.TrimLeft(appRoot, "/")),

old/provider/kubernetes/kubernetes_test.go

@@ -1308,6 +1308,18 @@ rateset:
 				),
 			),
 		),
+		buildIngress(
+			iNamespace("testing"),
+			iAnnotation(annotationKubernetesAppRoot, "/root"),
+			iRules(
+				iRule(
+					iHost("root3"),
+					iPaths(
+						onePath(iBackend("service1", intstr.FromInt(80))),
+					),
+				),
+			),
+		),
 		buildIngress(
 			iNamespace("testing"),
 			iAnnotation(annotationKubernetesIngressClass, "traefik"),
@@ -1518,6 +1530,11 @@ rateset:
 				servers(),
 				lbMethod("wrr"),
 			),
+			backend("root3",
+				servers(
+					server("http://example.com", weight(1))),
+				lbMethod("wrr"),
+			),
 			backend("protocol/valid",
 				servers(
 					server("h2c://example.com", weight(1)),
@@ -1684,6 +1701,13 @@ rateset:
 					route("root", "Host:root"),
 				),
 			),
+			frontend("root3",
+				passHostHeader(),
+				redirectRegex("root3$", "root3/root"),
+				routes(
+					route("root3", "Host:root3"),
+				),
+			),
 			frontend("protocol/valid",
 				passHostHeader(),
 				routes(