feat: HTTPRoute extensionRef filter converted onto plugin

Signed-off-by: Mattia Lavacca <lavacca.mattia@gmail.com>

internal/dataplane/parser/translate_httproute.go

@@ -270,8 +270,7 @@ func generateKongRoutesFromHTTPRouteMatches(
 
 	// if the redirect filter has not been set, we still need to set the route plugins
 	if !hasRedirectFilter {
-		plugins := translators.GeneratePluginsFromHTTPRouteFilters(filters, "", tags)
-		r.Plugins = append(r.Plugins, plugins...)
+		translators.ConvertFiltersToPlugins(&r, filters, "", tags)
 		routes = []kongstate.Route{r}
 	}
 
@@ -320,8 +319,7 @@ func getRoutesFromMatches(
 			}
 
 			// generate kong plugins from rule.filters
-			plugins := translators.GeneratePluginsFromHTTPRouteFilters(filters, path, tags)
-			matchRoute.Plugins = append(matchRoute.Plugins, plugins...)
+			translators.ConvertFiltersToPlugins(matchRoute, filters, path, tags)
 
 			routes = append(routes, *route)
 		} else {

internal/dataplane/parser/translators/httproute.go

@@ -9,6 +9,8 @@ import (
 
 	"github.com/kong/go-kong/kong"
 
+	"github.com/kong/kubernetes-ingress-controller/v2/internal/annotations"
+	"github.com/kong/kubernetes-ingress-controller/v2/internal/dataplane/kongstate"
 	"github.com/kong/kubernetes-ingress-controller/v2/internal/gatewayapi"
 )
 
@@ -350,14 +352,35 @@ func mustMarshalJSON[T any](val T) string {
 	return string(key)
 }
 
-// GeneratePluginsFromHTTPRouteFilters converts HTTPRouteFilter into Kong plugins.
+func ConvertFiltersToPlugins(route *kongstate.Route, filters []gatewayapi.HTTPRouteFilter, path string, tags []*string) {
+	plugins, pluginAnnotation := generatePluginsFromHTTPRouteFilters(filters, path, tags)
+	if route.Plugins == nil {
+		route.Plugins = make([]kong.Plugin, 0)
+	}
+	route.Plugins = append(route.Plugins, plugins...)
+	if len(pluginAnnotation) > 0 {
+		if route.Ingress.Annotations == nil {
+			route.Ingress.Annotations = make(map[string]string)
+		}
+		if _, ok := route.Ingress.Annotations[annotations.AnnotationPrefix+annotations.PluginsKey]; !ok {
+			route.Ingress.Annotations[annotations.AnnotationPrefix+annotations.PluginsKey] = pluginAnnotation
+		} else {
+			route.Ingress.Annotations[annotations.AnnotationPrefix+annotations.PluginsKey] = fmt.Sprintf("%s,%s",
+				route.Ingress.Annotations[annotations.AnnotationPrefix+annotations.PluginsKey],
+				pluginAnnotation)
+		}
+	}
+}
+
+// generatePluginsFromHTTPRouteFilters converts HTTPRouteFilter into Kong plugins.
 // path is the parameter to be used by the redirect plugin, to perform redirection.
-func GeneratePluginsFromHTTPRouteFilters(filters []gatewayapi.HTTPRouteFilter, path string, tags []*string) []kong.Plugin {
+func generatePluginsFromHTTPRouteFilters(filters []gatewayapi.HTTPRouteFilter, path string, tags []*string) ([]kong.Plugin, string) {
 	kongPlugins := make([]kong.Plugin, 0)
 	if len(filters) == 0 {
-		return kongPlugins
+		return kongPlugins, ""
 	}
 
+	var pluginsAnnotation string
 	for _, filter := range filters {
 		switch filter.Type {
 		case gatewayapi.HTTPRouteFilterRequestHeaderModifier:
@@ -369,8 +392,15 @@ func GeneratePluginsFromHTTPRouteFilters(filters []gatewayapi.HTTPRouteFilter, p
 		case gatewayapi.HTTPRouteFilterResponseHeaderModifier:
 			kongPlugins = append(kongPlugins, generateResponseHeaderModifierKongPlugin(filter.ResponseHeaderModifier))
 
-		case gatewayapi.HTTPRouteFilterExtensionRef,
-			gatewayapi.HTTPRouteFilterRequestMirror,
+		case gatewayapi.HTTPRouteFilterExtensionRef:
+			plugin := generateExtensionRefKongPlugin(filter.ExtensionRef)
+			if len(pluginsAnnotation) > 0 {
+				pluginsAnnotation = fmt.Sprintf("%s,%s", pluginsAnnotation, plugin)
+			} else {
+				pluginsAnnotation = plugin
+			}
+
+		case gatewayapi.HTTPRouteFilterRequestMirror,
 			gatewayapi.HTTPRouteFilterURLRewrite:
 			// not supported
 		}
@@ -381,7 +411,7 @@ func GeneratePluginsFromHTTPRouteFilters(filters []gatewayapi.HTTPRouteFilter, p
 		p.Tags = tags
 	}
 
-	return kongPlugins
+	return kongPlugins, pluginsAnnotation
 }
 
 // generateRequestRedirectKongPlugin generates configurations of plugins to satisfy the specification
@@ -429,6 +459,10 @@ func generateRequestRedirectKongPlugin(modifier *gatewayapi.HTTPRequestRedirectF
 	return plugins
 }
 
+func generateExtensionRefKongPlugin(modifier *gatewayapi.LocalObjectReference) string {
+	return string(modifier.Name)
+}
+
 // generateRequestHeaderModifierKongPlugin converts a gatewayapi.HTTPRequestHeaderFilter into a
 // kong.Plugin of type request-transformer.
 func generateRequestHeaderModifierKongPlugin(modifier *gatewayapi.HTTPHeaderFilter) kong.Plugin {

internal/dataplane/parser/translators/httproute_atc.go

@@ -66,8 +66,7 @@ func GenerateKongExpressionRoutesFromHTTPRouteMatches(
 
 	atc.ApplyExpression(&r.Route, routeMatcher, 1)
 	// generate plugins.
-	plugins := GeneratePluginsFromHTTPRouteFilters(translation.Filters, "", tags)
-	r.Plugins = plugins
+	ConvertFiltersToPlugins(&r, translation.Filters, "", tags)
 	return []kongstate.Route{r}, nil
 }
 
@@ -104,9 +103,7 @@ func generateKongExpressionRoutesWithRequestRedirectFilter(
 		if match.Path != nil && match.Path.Value != nil {
 			path = *match.Path.Value
 		}
-		plugins := GeneratePluginsFromHTTPRouteFilters(translation.Filters, path, tags)
-		matchRoute.Plugins = plugins
-
+		ConvertFiltersToPlugins(&matchRoute, translation.Filters, path, tags)
 		routes = append(routes, matchRoute)
 	}
 	return routes, nil
@@ -593,8 +590,7 @@ func KongExpressionRouteFromHTTPRouteMatchWithPriority(
 			path = *match.Match.Path.Value
 		}
 
-		plugins := GeneratePluginsFromHTTPRouteFilters(rule.Filters, path, tags)
-		r.Plugins = plugins
+		ConvertFiltersToPlugins(&r, rule.Filters, path, tags)
 	}
 
 	return r

internal/dataplane/parser/translators/httproute_test.go

@@ -12,10 +12,11 @@ import (
 
 func TestGeneratePluginsFromHTTPRouteFilters(t *testing.T) {
 	testCases := []struct {
-		name            string
-		filters         []gatewayapi.HTTPRouteFilter
-		path            string
-		expectedPlugins []kong.Plugin
+		name                      string
+		filters                   []gatewayapi.HTTPRouteFilter
+		path                      string
+		expectedPlugins           []kong.Plugin
+		expectedPluginsAnnotation string
 	}{
 		{
 			name:            "no filters",
@@ -153,13 +154,37 @@ func TestGeneratePluginsFromHTTPRouteFilters(t *testing.T) {
 				},
 			},
 		},
+		{
+			name: "extension-refs",
+			filters: []gatewayapi.HTTPRouteFilter{
+				{
+					Type: gatewayapi.HTTPRouteFilterExtensionRef,
+					ExtensionRef: &gatewayapi.LocalObjectReference{
+						Group: gatewayapi.Group("configuration.konghq.com/v1"),
+						Kind:  gatewayapi.Kind("KongPlugin"),
+						Name:  "plugin1",
+					},
+				},
+				{
+					Type: gatewayapi.HTTPRouteFilterExtensionRef,
+					ExtensionRef: &gatewayapi.LocalObjectReference{
+						Group: gatewayapi.Group("configuration.konghq.com/v1"),
+						Kind:  gatewayapi.Kind("KongPlugin"),
+						Name:  "plugin2",
+					},
+				},
+			},
+			expectedPluginsAnnotation: "plugin1,plugin2",
+			expectedPlugins:           []kong.Plugin{},
+		},
 	}
 
 	for _, tc := range testCases {
 		tc := tc
-		plugins := GeneratePluginsFromHTTPRouteFilters(tc.filters, tc.path, nil)
 		t.Run(tc.name, func(t *testing.T) {
+			plugins, pluginsAnnotation := generatePluginsFromHTTPRouteFilters(tc.filters, tc.path, nil)
 			require.Equal(t, tc.expectedPlugins, plugins)
+			require.Equal(t, tc.expectedPluginsAnnotation, pluginsAnnotation)
 		})
 	}
 }

internal/gatewayapi/aliases.go

@@ -40,6 +40,7 @@ type (
 	HTTPRouteList             = gatewayv1.HTTPRouteList
 	HTTPRouteMatch            = gatewayv1.HTTPRouteMatch
 	HTTPRouteRule             = gatewayv1.HTTPRouteRule
+	LocalObjectReference      = gatewayv1.LocalObjectReference
 	HTTPRouteSpec             = gatewayv1.HTTPRouteSpec
 	HTTPRouteStatus           = gatewayv1.HTTPRouteStatus
 	Hostname                  = gatewayv1.Hostname