fix per-route ratelimit option (Kuadrant#93)

* fix per-route ratelimit option

* add more context into the comment

* update example vHost EnvoyFilter comment

Author: rahulanand16nov

controllers/apim/ratelimitpolicy_controller.go

@@ -442,12 +442,6 @@ func routeRateLimitsPatch(vHostName string, routeName string, rateLimits []*apim
 		"operation": "MERGE",
 		"value": map[string]interface{}{
 			"route": map[string]interface{}{
-				"typed_per_filter_config": map[string]interface{}{
-					"envoy.filters.http.ratelimit": map[string]interface{}{
-						"@type":          "type.googleapis.com/envoy.extensions.filters.http.ratelimit.v3.RateLimitPerRoute",
-						"vh_rate_limits": "include",
-					},
-				},
 				"rate_limits": common.EnvoyFilterRatelimitsUnstructured(rateLimits),
 			},
 		},
@@ -502,10 +496,23 @@ func virtualHostRateLimitsPatch(vHostName string, rateLimits []*apimv1alpha1.Rat
 	//           - request_headers:
 	//               header_name: ":method"
 	//               descriptor_key: "req.method"
+	//     typed_per_filter_config:
+	//       envoy.filters.http.ratelimit:
+	//         @type: "type.googleapis.com/envoy.extensions.filters.http.ratelimit.v3.RateLimitPerRoute"
+	//         vh_rate_limits: INCLUDE
 	patchUnstructured := map[string]interface{}{
 		"operation": "MERGE",
 		"value": map[string]interface{}{
 			"rate_limits": common.EnvoyFilterRatelimitsUnstructured(rateLimits),
+			"typed_per_filter_config": map[string]interface{}{
+				// Note the following name is different from what we have given to our pre/post-auth
+				// ratelimit filters. It's because you refer to the type of filter and not the name field
+				// of the filter. This infers it's configured for both filters in our case.
+				"envoy.filters.http.ratelimit": map[string]interface{}{
+					"@type":          "type.googleapis.com/envoy.extensions.filters.http.ratelimit.v3.RateLimitPerRoute",
+					"vh_rate_limits": "INCLUDE",
+				},
+			},
 		},
 	}