[wip] fix: filter hosts in httproutes

internal/controllers/gateway/httproute_controller.go

@@ -319,7 +319,12 @@ func (r *HTTPRouteReconciler) Reconcile(ctx context.Context, req ctrl.Request) (
 	// perform operations on the kong store only if the route is in accepted status
 	if isRouteAccepted(gateways) {
 		// remove all the hostnames that don't match with at least one Listener's Hostname
-		filteredHTTPRoute := filterHostnames(gateways, httproute.DeepCopy())
+		filteredHTTPRoute, err := filterHostnames(gateways, httproute.DeepCopy())
+
+		if err != nil {
+			debug(log, httproute, "no matching hostnames after filtering")
+			return ctrl.Result{}, err
+		}
 
 		// if the gateways are ready, and the HTTPRoute is destined for them, ensure that
 		// the object is pushed to the dataplane.

internal/controllers/gateway/route_utils.go

@@ -313,20 +313,33 @@ func listenerHostnameIntersectWithRouteHostnames[H types.HostnameT, L types.List
 	return false
 }
 
+// shouldListenerSpecifyHostname if the listener could specify an effective hostname to match hostnames in requests.
+// it will return true when the protocol of listener is HTTP, HTTPS, or TLS.
+func shouldListenerSpecifyHostname(listener *gatewayv1beta1.Listener) bool {
+	return listener.Protocol == gatewayv1beta1.HTTPProtocolType ||
+		listener.Protocol == gatewayv1beta1.HTTPSProtocolType ||
+		listener.Protocol == gatewayv1beta1.TLSProtocolType
+}
+
 // filterHostnames accepts a HTTPRoute and returns a version of the same object with only a subset of the
 // hostnames, the ones matching with the listeners' hostname.
-func filterHostnames(gateways []supportedGatewayWithCondition, httpRoute *gatewayv1beta1.HTTPRoute) *gatewayv1beta1.HTTPRoute {
+// it returns an error if the intersection of hostname match in httproute and listeners is empty.
+func filterHostnames(gateways []supportedGatewayWithCondition, httpRoute *gatewayv1beta1.HTTPRoute) (*gatewayv1beta1.HTTPRoute, error) {
 	filteredHostnames := make([]gatewayv1beta1.Hostname, 0)
 
 	// if no hostnames are specified in the route spec, get all the hostnames from
 	// the gateway
 	if len(httpRoute.Spec.Hostnames) == 0 {
 		for _, gateway := range gateways {
 			for _, listener := range gateway.gateway.Spec.Listeners {
-				if listenerName := gateway.listenerName; listenerName == "" || listenerName == string(listener.Name) {
-					if listener.Hostname != nil {
-						filteredHostnames = append(filteredHostnames, (*listener.Hostname))
+				if listenerName := gateway.listenerName; listenerName == "" || listenerName == string(listener.Name) &&
+					shouldListenerSpecifyHostname(&listener) {
+					// httpRoute remains an empty hostname if any of the listeners
+					// has not specified hostname to match any host.
+					if listener.Hostname == nil {
+						return httpRoute, nil
 					}
+					filteredHostnames = append(filteredHostnames, (*listener.Hostname))
 				}
 			}
 		}
@@ -336,10 +349,13 @@ func filterHostnames(gateways []supportedGatewayWithCondition, httpRoute *gatewa
 				filteredHostnames = append(filteredHostnames, hostnameMatching)
 			}
 		}
+		if len(filteredHostnames) == 0 {
+			return nil, fmt.Errorf("no matching host")
+		}
 	}
 
 	httpRoute.Spec.Hostnames = filteredHostnames
-	return httpRoute
+	return httpRoute, nil
 }
 
 // getMinimumHostnameIntersection returns the minimum intersecting hostname, in the sense that:

internal/controllers/gateway/route_utils_test.go

@@ -182,7 +182,8 @@ func TestFilterHostnames(t *testing.T) {
 	}
 
 	for _, tc := range testCases {
-		filteredHTTPRoute := filterHostnames(tc.gateways, tc.httpRoute)
+		filteredHTTPRoute, err := filterHostnames(tc.gateways, tc.httpRoute)
+		assert.NoError(t, err)
 		assert.Equal(t, tc.expectedHTTPRoute.Spec, filteredHTTPRoute.Spec, tc.name)
 	}
 }