/*
 * Copyright 2023 Google LLC
 *
 * 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 quilkin.relay.v1alpha1;

import "envoy/service/discovery/v3/discovery.proto";

// The Manager Discovery Service provides an RPC for a management
// service to upstream its configuration to a relay service.
// This RPC works essentially the same as xDS, except instead of the
// client connecting to the server to receive configuration, the
// client is connecting to the server send its configuration.
//
// This service enables the relay to merge the configuration of all
// currently live management servers as a single aggregated
// xDS server without the relay needing to maintain a list
// of xDS servers to connect to in the relay itself.
service AggregatedControlPlaneDiscoveryService {
  // This RPC is not supported but remains here as part of the xDS standard,
  // as Quilkin only uses a delta configuration transport for performance reasons.
  rpc StreamAggregatedResources(
      stream envoy.service.discovery.v3.DiscoveryResponse)
      returns (stream envoy.service.discovery.v3.DiscoveryRequest) {}

  // Delta (Incremental) xDS implementation
  rpc DeltaAggregatedResources(
      stream envoy.service.discovery.v3.DeltaDiscoveryResponse)
      returns (stream envoy.service.discovery.v3.DeltaDiscoveryRequest) {}
}