// Copyright 2025 Envoy Project Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// 
//     http://www.apache.org/licenses/LICENSE-2.0
// 
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

syntax = "proto3";

package envoy.extensions.filters.http.grpc_http1_reverse_bridge.v3;

import "udpa/annotations/status.proto";
import "udpa/annotations/versioning.proto";
import "validate/validate.proto";

option java_package = "io.envoyproxy.envoy.extensions.filters.http.grpc_http1_reverse_bridge.v3";
option java_outer_classname = "ConfigProto";
option java_multiple_files = true;
option go_package = "github.com/envoyproxy/go-control-plane/envoy/extensions/filters/http/grpc_http1_reverse_bridge/v3;grpc_http1_reverse_bridgev3";
option (udpa.annotations.file_status).package_version_status = ACTIVE;

// [#protodoc-title: gRPC HTTP/1.1 Reverse Bridge]
// gRPC HTTP/1.1 Reverse Bridge :ref:`configuration overview
// <config_http_filters_grpc_http1_reverse_bridge>`.
// [#extension: envoy.filters.http.grpc_http1_reverse_bridge]

// gRPC reverse bridge filter configuration
message FilterConfig {
  option (udpa.annotations.versioning).previous_message_type =
      "envoy.config.filter.http.grpc_http1_reverse_bridge.v2alpha1.FilterConfig";

  // The content-type to pass to the upstream when the gRPC bridge filter is applied.
  // The filter will also validate that the upstream responds with the same content type.
  string content_type = 1 [(validate.rules).string = {min_len: 1}];

  // If true, Envoy will assume that the upstream doesn't understand gRPC frames and
  // strip the gRPC frame from the request, and add it back in to the response. This will
  // hide the gRPC semantics from the upstream, allowing it to receive and respond with a
  // simple binary encoded protobuf. In order to calculate the ``Content-Length`` header value, Envoy
  // will buffer the upstream response unless :ref:`response_size_header
  // <envoy_v3_api_field_extensions.filters.http.grpc_http1_reverse_bridge.v3.FilterConfig.response_size_header>`
  // is set, in which case Envoy will use the value of an upstream header to calculate the content
  // length.
  bool withhold_grpc_frames = 2;

  // When :ref:`withhold_grpc_frames
  // <envoy_v3_api_field_extensions.filters.http.grpc_http1_reverse_bridge.v3.FilterConfig.withhold_grpc_frames>`
  // is true, this option controls how Envoy calculates the ``Content-Length``. When
  // ``response_size_header`` is empty, Envoy will buffer the upstream response to calculate its
  // size. When ``response_size_header`` is set to a non-empty string, Envoy will stream the response
  // to the downstream and it will use the value of the response header with this name to set the
  // ``Content-Length`` header and gRPC frame size. If the header with this name is repeated, only
  // the first value will be used.
  //
  // Envoy will treat the upstream response as an error if this option is specified and the header
  // is missing or if the value does not match the actual response body size.
  string response_size_header = 3
      [(validate.rules).string = {well_known_regex: HTTP_HEADER_NAME strict: false}];
}

// gRPC reverse bridge filter configuration per virtualhost/route/weighted-cluster level.
message FilterConfigPerRoute {
  option (udpa.annotations.versioning).previous_message_type =
      "envoy.config.filter.http.grpc_http1_reverse_bridge.v2alpha1.FilterConfigPerRoute";

  // If true, disables gRPC reverse bridge filter for this particular vhost or route.
  // If disabled is specified in multiple per-filter-configs, the most specific one will be used.
  bool disabled = 1;
}
