From cf6e08238525235d8b83a2f47d1196fc7e80f983 Mon Sep 17 00:00:00 2001
From: Ashing Zheng <axingfly@gmail.com>
Date: Fri, 24 Oct 2025 16:41:55 +0800
Subject: [PATCH] feat: support kubernetes.io/ingress.class annotations (#2615)

Signed-off-by: Ashing Zheng <axingfly@gmail.com>
(cherry picked from commit cbfa038979158331de65b20aeb489b478b581697)
---
 internal/controller/utils.go |  3 ++
 internal/types/k8s.go        |  9 ++++++
 test/e2e/ingress/ingress.go  | 62 ++++++++++++++++++++++++++++++++++++
 3 files changed, 74 insertions(+)

diff --git a/internal/controller/utils.go b/internal/controller/utils.go
index f02e7326..e3bdcd80 100644
--- a/internal/controller/utils.go
+++ b/internal/controller/utils.go
@@ -41,7 +41,10 @@ import (
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/labels"
 	k8stypes "k8s.io/apimachinery/pkg/types"
+<<<<<<< HEAD
 	ctrl "sigs.k8s.io/controller-runtime"
+=======
+>>>>>>> cbfa0389 (feat: support kubernetes.io/ingress.class annotations (#2615))
 	"sigs.k8s.io/controller-runtime/pkg/client"
 	"sigs.k8s.io/controller-runtime/pkg/event"
 	"sigs.k8s.io/controller-runtime/pkg/handler"
diff --git a/internal/types/k8s.go b/internal/types/k8s.go
index 42e1f7fb..433538ce 100644
--- a/internal/types/k8s.go
+++ b/internal/types/k8s.go
@@ -22,9 +22,13 @@ import (
 	netv1 "k8s.io/api/networking/v1"
 	netv1beta1 "k8s.io/api/networking/v1beta1"
 	"k8s.io/apimachinery/pkg/runtime/schema"
+<<<<<<< HEAD
 	kschema "k8s.io/client-go/kubernetes/scheme"
 	"k8s.io/utils/ptr"
 	"sigs.k8s.io/controller-runtime/pkg/client"
+=======
+	"k8s.io/utils/ptr"
+>>>>>>> cbfa0389 (feat: support kubernetes.io/ingress.class annotations (#2615))
 	gatewayv1 "sigs.k8s.io/gateway-api/apis/v1"
 	gatewayv1alpha2 "sigs.k8s.io/gateway-api/apis/v1alpha2"
 	gatewayv1beta1 "sigs.k8s.io/gateway-api/apis/v1beta1"
@@ -215,6 +219,11 @@ func GvkOf(obj any) schema.GroupVersionKind {
 	}
 }
 
+<<<<<<< HEAD
+=======
+// GetEffectiveIngressClassName returns the effective ingress class name.
+// It first checks spec.IngressClassName, and falls back to the annotation if spec is empty.
+>>>>>>> cbfa0389 (feat: support kubernetes.io/ingress.class annotations (#2615))
 func GetEffectiveIngressClassName(ingress *netv1.Ingress) string {
 	if cls := ptr.Deref(ingress.Spec.IngressClassName, ""); cls != "" {
 		return cls
diff --git a/test/e2e/ingress/ingress.go b/test/e2e/ingress/ingress.go
index 06886716..f928f16a 100644
--- a/test/e2e/ingress/ingress.go
+++ b/test/e2e/ingress/ingress.go
@@ -1117,4 +1117,66 @@ spec:
 				Should(Equal("enabled"))
 		})
 	})
+
+	Context("Ingress with annotation-based IngressClass", func() {
+		const ingressClassSpec = `
+apiVersion: networking.k8s.io/v1
+kind: IngressClass
+metadata:
+  name: %s
+spec:
+  controller: "%s"
+  parameters:
+    apiGroup: "apisix.apache.org"
+    kind: "GatewayProxy"
+    name: "apisix-proxy-config"
+    namespace: %s
+    scope: "Namespace"
+`
+		const ingressSpec = `
+apiVersion: networking.k8s.io/v1
+kind: Ingress
+metadata:
+  name: apisix-ingress-annotation
+  annotations:
+    kubernetes.io/ingress.class: %s
+spec:
+  rules:
+  - host: annotation.example.com
+    http:
+      paths:
+      - path: /get
+        pathType: Prefix
+        backend:
+          service:
+            name: httpbin-service-e2e-test
+            port:
+              number: 80
+`
+
+		It("Ingress with kubernetes.io/ingress.class annotation", func() {
+			By("create GatewayProxy")
+			gatewayProxy := fmt.Sprintf(gatewayProxyYaml, s.Namespace(), s.Deployer.GetAdminEndpoint(), s.AdminKey())
+			err := s.CreateResourceFromStringWithNamespace(gatewayProxy, s.Namespace())
+			Expect(err).NotTo(HaveOccurred(), "creating GatewayProxy")
+			time.Sleep(5 * time.Second)
+
+			By("create IngressClass")
+			err = s.CreateResourceFromStringWithNamespace(fmt.Sprintf(ingressClassSpec, s.Namespace(), s.GetControllerName(), s.Namespace()), s.Namespace())
+			Expect(err).NotTo(HaveOccurred(), "creating IngressClass")
+
+			By("create Ingress with annotation")
+			err = s.CreateResourceFromStringWithNamespace(fmt.Sprintf(ingressSpec, s.Namespace()), s.Namespace())
+			Expect(err).NotTo(HaveOccurred(), "creating Ingress with annotation")
+
+			By("verify Ingress with annotation works")
+			Eventually(func() int {
+				return s.NewAPISIXClient().
+					GET("/get").
+					WithHost("annotation.example.com").
+					Expect().Raw().StatusCode
+			}).WithTimeout(20 * time.Second).ProbeEvery(time.Second).
+				Should(Equal(http.StatusOK))
+		})
+	})
 })