Ratelimit: Add optional descriptor key to generic_key action

api/envoy/config/route/v3/route_components.proto

@@ -1546,6 +1546,10 @@ message RateLimit {
 
       // The value to use in the descriptor entry.
       string descriptor_value = 1 [(validate.rules).string = {min_bytes: 1}];
+
+      // An optional key to use in the descriptor entry. If not set it defaults
+      // to 'generic_key' as the descriptor key.
+      string descriptor_key = 2;
     }
 
     // The following descriptor entry is appended to the descriptor:

docs/root/version_history/current.rst

@@ -66,6 +66,7 @@ New Features
 * overload management: add :ref:`scaling <envoy_v3_api_field_config.overload.v3.Trigger.scaled>` trigger for OverloadManager actions.
 * postgres network filter: :ref:`metadata <config_network_filters_postgres_proxy_dynamic_metadata>` is produced based on SQL query.
 * ratelimit: added :ref:`enable_x_ratelimit_headers <envoy_v3_api_msg_extensions.filters.http.ratelimit.v3.RateLimit>` option to enable `X-RateLimit-*` headers as defined in `draft RFC <https://tools.ietf.org/id/draft-polli-ratelimit-headers-03.html>`_.
+* ratelimit: added support for optional :ref:`descriptor_key <envoy_v3_api_field_config.route.v3.RateLimit.Action.generic_key>` to Generic Key action.
 * rbac filter: added a log action to the :ref:`RBAC filter <envoy_v3_api_msg_config.rbac.v3.RBAC>` which sets dynamic metadata to inform access loggers whether to log.
 * redis: added fault injection support :ref:`fault injection for redis proxy <envoy_v3_api_field_extensions.filters.network.redis_proxy.v3.RedisProxy.faults>`, described further in :ref:`configuration documentation <config_network_filters_redis_proxy>`.
 * router: added a new :ref:`rate limited retry back off <envoy_v3_api_msg_config.route.v3.RetryPolicy.RateLimitedRetryBackOff>` strategy that uses headers like `Retry-After` or `X-RateLimit-Reset` to decide the back off interval.

source/common/router/router_ratelimit.cc

@@ -97,7 +97,7 @@ bool GenericKeyAction::populateDescriptor(const Router::RouteEntry&,
                                           RateLimit::Descriptor& descriptor, const std::string&,
                                           const Http::HeaderMap&, const Network::Address::Instance&,
                                           const envoy::config::core::v3::Metadata*) const {
-  descriptor.entries_.push_back({"generic_key", descriptor_value_});
+  descriptor.entries_.push_back({descriptor_key_, descriptor_value_});
   return true;
 }
 

source/common/router/router_ratelimit.h

@@ -98,7 +98,9 @@ class RemoteAddressAction : public RateLimitAction {
 class GenericKeyAction : public RateLimitAction {
 public:
   GenericKeyAction(const envoy::config::route::v3::RateLimit::Action::GenericKey& action)
-      : descriptor_value_(action.descriptor_value()) {}
+      : descriptor_value_(action.descriptor_value()),
+        descriptor_key_(!action.descriptor_key().empty() ? action.descriptor_key()
+                                                         : "generic_key") {}
 
   // Router::RateLimitAction
   bool populateDescriptor(const Router::RouteEntry& route, RateLimit::Descriptor& descriptor,
@@ -108,6 +110,7 @@ class GenericKeyAction : public RateLimitAction {
 
 private:
   const std::string descriptor_value_;
+  const std::string descriptor_key_;
 };
 
 /**

test/common/router/router_ratelimit_test.cc

@@ -449,6 +449,38 @@ TEST_F(RateLimitPolicyEntryTest, RateLimitKey) {
               testing::ContainerEq(descriptors_));
 }
 
+TEST_F(RateLimitPolicyEntryTest, GenericKeyWithSetDescriptorKey) {
+  const std::string yaml = R"EOF(
+actions:
+- generic_key:
+    descriptor_key: fake_key
+    descriptor_value: fake_value
+  )EOF";
+
+  setupTest(yaml);
+
+  rate_limit_entry_->populateDescriptors(route_, descriptors_, "", header_, default_remote_address_,
+                                         dynamic_metadata_);
+  EXPECT_THAT(std::vector<Envoy::RateLimit::Descriptor>({{{{"fake_key", "fake_value"}}}}),
+              testing::ContainerEq(descriptors_));
+}
+
+TEST_F(RateLimitPolicyEntryTest, GenericKeyWithEmptyDescriptorKey) {
+  const std::string yaml = R"EOF(
+actions:
+- generic_key:
+    descriptor_key: ""
+    descriptor_value: fake_value
+  )EOF";
+
+  setupTest(yaml);
+
+  rate_limit_entry_->populateDescriptors(route_, descriptors_, "", header_, default_remote_address_,
+                                         dynamic_metadata_);
+  EXPECT_THAT(std::vector<Envoy::RateLimit::Descriptor>({{{{"generic_key", "fake_value"}}}}),
+              testing::ContainerEq(descriptors_));
+}
+
 TEST_F(RateLimitPolicyEntryTest, DynamicMetaDataMatch) {
   const std::string yaml = R"EOF(
 actions: