local rate limit: add new rate_limits support to the filter (#36099)

Commit Message: local rate limit: add new rate_limits api to the
filter's api
Additional Description:

In the previous local rate limit, the
[rate_limits](https://www.envoyproxy.io/docs/envoy/latest/api-v3/config/route/v3/route_components.proto#envoy-v3-api-field-config-route-v3-virtualhost-rate-limits)
field of route is used to generate the descriptor entries. Then the
generated entries will be used to match a token bucket which is
configured in the filter configs (route level, vhost level, etc).

However, it make the configuration very complex, and cannot cover some
common scenarios easily. For example, give a specific virtual host X and
a special route Y that under this virtual host X.

We want to provides a virtual host level rate limit for the specific
virtual host X, and a route level rate limit for the specific route Y.
We hope the configuration of virtual host could works for all routes
except the Y.

For most filters, this requirement could be achieved by getting the most
specific filter config and applying it. But for the local rate limit,
thing become very complex. Because the rate limit configuration is split
into `rate_limits` field of route and the filter config. The local rate
limit need to handle these relationship carefully.

This PR try to simplify it.

Risk Level: low.
Testing: n/a.
Docs Changes: n/a.
Release Notes: n/a.
Platform Specific Features: n/a.

---------

Signed-off-by: wangbaiping <[email protected]>
Signed-off-by: code <[email protected]>
Co-authored-by: Matt Klein <[email protected]>

Mirrored from https://github.com/envoyproxy/envoy @ e48666365c8a0b3a62343602fd9380d58a7afd95

envoy/extensions/filters/http/local_ratelimit/v3/BUILD

@@ -7,6 +7,7 @@ licenses(["notice"])  # Apache 2
 api_proto_package(
     deps = [
         "//envoy/config/core/v3:pkg",
+        "//envoy/config/route/v3:pkg",
         "//envoy/extensions/common/ratelimit/v3:pkg",
         "//envoy/type/v3:pkg",
         "@com_github_cncf_xds//udpa/annotations:pkg",

envoy/extensions/filters/http/local_ratelimit/v3/local_rate_limit.proto

@@ -3,6 +3,7 @@ syntax = "proto3";
 package envoy.extensions.filters.http.local_ratelimit.v3;
 
 import "envoy/config/core/v3/base.proto";
+import "envoy/config/route/v3/route_components.proto";
 import "envoy/extensions/common/ratelimit/v3/ratelimit.proto";
 import "envoy/type/v3/http_status.proto";
 import "envoy/type/v3/token_bucket.proto";
@@ -22,7 +23,7 @@ option (udpa.annotations.file_status).package_version_status = ACTIVE;
 // Local Rate limit :ref:`configuration overview <config_http_filters_local_rate_limit>`.
 // [#extension: envoy.filters.http.local_ratelimit]
 
-// [#next-free-field: 17]
+// [#next-free-field: 18]
 message LocalRateLimit {
   // The human readable prefix to use when emitting stats.
   string stat_prefix = 1 [(validate.rules).string = {min_len: 1}];
@@ -147,4 +148,23 @@ message LocalRateLimit {
   // of the default ``UNAVAILABLE`` gRPC code for a rate limited gRPC call. The
   // HTTP code will be 200 for a gRPC response.
   bool rate_limited_as_resource_exhausted = 15;
+
+  // Rate limit configuration that is used to generate a list of descriptor entries based on
+  // the request context. The generated entries will be used to find one or multiple matched rate
+  // limit rule from the ``descriptors``.
+  // If this is set, then
+  // :ref:`VirtualHost.rate_limits<envoy_v3_api_field_config.route.v3.VirtualHost.rate_limits>` or
+  // :ref:`RouteAction.rate_limits<envoy_v3_api_field_config.route.v3.RouteAction.rate_limits>` fields
+  // will be ignored.
+  //
+  // .. note::
+  //   Not all configuration fields of
+  //   :ref:`rate limit config <envoy_v3_api_msg_config.route.v3.RateLimit>` is supported at here.
+  //   Following fields are not supported:
+  //
+  //   1. :ref:`rate limit stage <envoy_v3_api_field_config.route.v3.RateLimit.stage>`.
+  //   2. :ref:`dynamic metadata <envoy_v3_api_field_config.route.v3.RateLimit.Action.dynamic_metadata>`.
+  //   3. :ref:`disable_key <envoy_v3_api_field_config.route.v3.RateLimit.disable_key>`.
+  //   4. :ref:`override limit <envoy_v3_api_field_config.route.v3.RateLimit.limit>`.
+  repeated config.route.v3.RateLimit rate_limits = 17;
 }