Support Gateway API reference grant for HTTPRoute backends

Co-authored-by: Kevin Pollet <pollet.kevin@gmail.com>

pkg/provider/kubernetes/gateway/fixtures/referencegrant/for_service.yml

@@ -0,0 +1,61 @@
+---
+apiVersion: gateway.networking.k8s.io/v1beta1
+kind: ReferenceGrant
+metadata:
+  name: backend-from-bar
+  namespace: bar
+spec:
+  from:
+    - group: gateway.networking.k8s.io
+      kind: HTTPRoute
+      namespace: default
+  to:
+    - group: ""
+      kind: Service
+
+---
+apiVersion: gateway.networking.k8s.io/v1
+kind: GatewayClass
+metadata:
+  name: my-gateway-class
+spec:
+  controllerName: traefik.io/gateway-controller
+
+---
+apiVersion: gateway.networking.k8s.io/v1
+kind: Gateway
+metadata:
+  name: my-gateway
+  namespace: default
+spec:
+  gatewayClassName: my-gateway-class
+  listeners: # Use GatewayClass defaults for listener definition.
+    - name: http
+      protocol: HTTP
+      port: 80
+      hostname: foo.example.com
+      allowedRoutes:
+        kinds:
+          - kind: HTTPRoute
+            group: gateway.networking.k8s.io
+        namespaces:
+          from: Same
+
+---
+apiVersion: gateway.networking.k8s.io/v1
+kind: HTTPRoute
+metadata:
+  name: http-app-1
+  namespace: default
+spec:
+  parentRefs:
+    - name: my-gateway
+      kind: Gateway
+      group: gateway.networking.k8s.io
+  rules:
+    - backendRefs:
+        - name: whoami-bar
+          port: 80
+          weight: 1
+          kind: Service
+          group: ""

pkg/provider/kubernetes/gateway/fixtures/referencegrant/for_service_missing.yml

@@ -0,0 +1,46 @@
+---
+apiVersion: gateway.networking.k8s.io/v1
+kind: GatewayClass
+metadata:
+  name: my-gateway-class
+spec:
+  controllerName: traefik.io/gateway-controller
+
+---
+apiVersion: gateway.networking.k8s.io/v1
+kind: Gateway
+metadata:
+  name: my-gateway
+  namespace: default
+spec:
+  gatewayClassName: my-gateway-class
+  listeners: # Use GatewayClass defaults for listener definition.
+    - name: http
+      protocol: HTTP
+      port: 80
+      hostname: foo.example.com
+      allowedRoutes:
+        kinds:
+          - kind: HTTPRoute
+            group: gateway.networking.k8s.io
+        namespaces:
+          from: Same
+
+---
+apiVersion: gateway.networking.k8s.io/v1
+kind: HTTPRoute
+metadata:
+  name: http-app-1
+  namespace: default
+spec:
+  parentRefs:
+    - name: my-gateway
+      kind: Gateway
+      group: gateway.networking.k8s.io
+  rules:
+    - backendRefs:
+        - name: whoami-bar
+          port: 80
+          weight: 1
+          kind: Service
+          group: ""

pkg/provider/kubernetes/gateway/fixtures/referencegrant/for_service_not_matching_from.yml

@@ -0,0 +1,61 @@
+---
+apiVersion: gateway.networking.k8s.io/v1beta1
+kind: ReferenceGrant
+metadata:
+  name: backend-from-bar
+  namespace: bar
+spec:
+  from:
+    - group: gateway.networking.k8s.io
+      kind: HTTPRoute
+      namespace: anothernamespce
+  to:
+    - group: ""
+      kind: Service
+
+---
+apiVersion: gateway.networking.k8s.io/v1
+kind: GatewayClass
+metadata:
+  name: my-gateway-class
+spec:
+  controllerName: traefik.io/gateway-controller
+
+---
+apiVersion: gateway.networking.k8s.io/v1
+kind: Gateway
+metadata:
+  name: my-gateway
+  namespace: default
+spec:
+  gatewayClassName: my-gateway-class
+  listeners: # Use GatewayClass defaults for listener definition.
+    - name: http
+      protocol: HTTP
+      port: 80
+      hostname: foo.example.com
+      allowedRoutes:
+        kinds:
+          - kind: HTTPRoute
+            group: gateway.networking.k8s.io
+        namespaces:
+          from: Same
+
+---
+apiVersion: gateway.networking.k8s.io/v1
+kind: HTTPRoute
+metadata:
+  name: http-app-1
+  namespace: default
+spec:
+  parentRefs:
+    - name: my-gateway
+      kind: Gateway
+      group: gateway.networking.k8s.io
+  rules:
+    - backendRefs:
+        - name: whoami-bar
+          port: 80
+          weight: 1
+          kind: Service
+          group: ""

pkg/provider/kubernetes/gateway/fixtures/referencegrant/for_service_not_matching_to.yml

@@ -0,0 +1,62 @@
+---
+apiVersion: gateway.networking.k8s.io/v1beta1
+kind: ReferenceGrant
+metadata:
+  name: backend-from-bar
+  namespace: bar
+spec:
+  from:
+    - group: gateway.networking.k8s.io
+      kind: HTTPRoute
+      namespace: default
+  to:
+    - group: ""
+      kind: Service
+      name: differentservice
+
+---
+apiVersion: gateway.networking.k8s.io/v1
+kind: GatewayClass
+metadata:
+  name: my-gateway-class
+spec:
+  controllerName: traefik.io/gateway-controller
+
+---
+apiVersion: gateway.networking.k8s.io/v1
+kind: Gateway
+metadata:
+  name: my-gateway
+  namespace: default
+spec:
+  gatewayClassName: my-gateway-class
+  listeners: # Use GatewayClass defaults for listener definition.
+    - name: http
+      protocol: HTTP
+      port: 80
+      hostname: foo.example.com
+      allowedRoutes:
+        kinds:
+          - kind: HTTPRoute
+            group: gateway.networking.k8s.io
+        namespaces:
+          from: Same
+
+---
+apiVersion: gateway.networking.k8s.io/v1
+kind: HTTPRoute
+metadata:
+  name: http-app-1
+  namespace: default
+spec:
+  parentRefs:
+    - name: my-gateway
+      kind: Gateway
+      group: gateway.networking.k8s.io
+  rules:
+    - backendRefs:
+        - name: whoami-bar
+          port: 80
+          weight: 1
+          kind: Service
+          group: ""