From f5302840316f4a81267ea77828d2569778bc2ef5 Mon Sep 17 00:00:00 2001
From: Regner Blok-Andersen <shadowdf@gmail.com>
Date: Fri, 3 Mar 2017 11:30:22 -0800
Subject: [PATCH] Adding support for Traefik to respect the K8s ingress class
 annotation (#1182)

---
 docs/user-guide/kubernetes.md | 14 +++++++++++++-
 provider/kubernetes.go        | 15 +++++++++++++++
 provider/kubernetes_test.go   | 29 +++++++++++++++++++++++++++++
 3 files changed, 57 insertions(+), 1 deletion(-)

diff --git a/docs/user-guide/kubernetes.md b/docs/user-guide/kubernetes.md
index 44eb68a96..e489f403a 100644
--- a/docs/user-guide/kubernetes.md
+++ b/docs/user-guide/kubernetes.md
@@ -123,6 +123,8 @@ kind: Ingress
 metadata:
   name: traefik-web-ui
   namespace: kube-system
+  annotations:
+    kubernetes.io/ingress.class: traefik
 spec:
   rules:
   - host: traefik-ui.local
@@ -328,6 +330,8 @@ apiVersion: extensions/v1beta1
 kind: Ingress
 metadata:
   name: cheese
+  annotations:
+    kubernetes.io/ingress.class: traefik
 spec:
   rules:
   - host: stilton.local
@@ -390,6 +394,7 @@ kind: Ingress
 metadata:
   name: cheeses
   annotations:
+    kubernetes.io/ingress.class: traefik
     traefik.frontend.rule.type: pathprefixstrip
 spec:
   rules:
@@ -451,6 +456,7 @@ kind: Ingress
 metadata:
   name: example
   annotations:
+    kubernetes.io/ingress.class: traefik
     traefik.frontend.passHostHeader: "false"
 spec:
   rules:
@@ -483,4 +489,10 @@ request with the Host header being static.otherdomain.com.
 
 Note: The per ingress annotation overides whatever the global value is set to. So you
 could set `disablePassHostHeaders` to true in your toml file and then enable passing
-the host header per ingress if you wanted.
\ No newline at end of file
+the host header per ingress if you wanted.
+
+## Excluding an ingress from Træfɪk
+You can control which ingress Træfɪk cares about by using the "kubernetes.io/ingress.class"
+annotation. By default if the annotation is not set at all Træfɪk will include the
+ingress. If the annotation is set to anything other than traefik or a blank string
+Træfɪk will ignore it.
\ No newline at end of file
diff --git a/provider/kubernetes.go b/provider/kubernetes.go
index a7dce2a01..cb6327d70 100644
--- a/provider/kubernetes.go
+++ b/provider/kubernetes.go
@@ -116,6 +116,12 @@ func (provider *Kubernetes) loadIngresses(k8sClient k8s.Client) (*types.Configur
 		map[string]*types.Frontend{},
 	}
 	for _, i := range ingresses {
+		ingressClass := i.Annotations["kubernetes.io/ingress.class"]
+
+		if !shouldProcessIngress(ingressClass) {
+			continue
+		}
+
 		for _, r := range i.Spec.Rules {
 			if r.HTTP == nil {
 				log.Warnf("Error in ingress: HTTP is nil")
@@ -281,6 +287,15 @@ func equalPorts(servicePort v1.ServicePort, ingressPort intstr.IntOrString) bool
 	return false
 }
 
+func shouldProcessIngress(ingressClass string) bool {
+	switch ingressClass {
+	case "", "traefik":
+		return true
+	default:
+		return false
+	}
+}
+
 func (provider *Kubernetes) getPassHostHeader() bool {
 	if provider.DisablePassHostHeaders {
 		return false
diff --git a/provider/kubernetes_test.go b/provider/kubernetes_test.go
index 7213d548e..667662e63 100644
--- a/provider/kubernetes_test.go
+++ b/provider/kubernetes_test.go
@@ -1492,6 +1492,7 @@ func TestIngressAnnotations(t *testing.T) {
 			ObjectMeta: v1.ObjectMeta{
 				Namespace: "testing",
 				Annotations: map[string]string{
+					"kubernetes.io/ingress.class":     "traefik",
 					"traefik.frontend.passHostHeader": "true",
 				},
 			},
@@ -1516,6 +1517,34 @@ func TestIngressAnnotations(t *testing.T) {
 				},
 			},
 		},
+		{
+			ObjectMeta: v1.ObjectMeta{
+				Namespace: "testing",
+				Annotations: map[string]string{
+					"kubernetes.io/ingress.class": "somethingOtherThanTraefik",
+				},
+			},
+			Spec: v1beta1.IngressSpec{
+				Rules: []v1beta1.IngressRule{
+					{
+						Host: "herp",
+						IngressRuleValue: v1beta1.IngressRuleValue{
+							HTTP: &v1beta1.HTTPIngressRuleValue{
+								Paths: []v1beta1.HTTPIngressPath{
+									{
+										Path: "/derp",
+										Backend: v1beta1.IngressBackend{
+											ServiceName: "service2",
+											ServicePort: intstr.FromInt(80),
+										},
+									},
+								},
+							},
+						},
+					},
+				},
+			},
+		},
 	}
 	services := []*v1.Service{
 		{