1 // 2 // Copyright 2022 gRPC authors. 3 // 4 // Licensed under the Apache License, Version 2.0 (the "License"); 5 // you may not use this file except in compliance with the License. 6 // You may obtain a copy of the License at 7 // 8 // http://www.apache.org/licenses/LICENSE-2.0 9 // 10 // Unless required by applicable law or agreed to in writing, software 11 // distributed under the License is distributed on an "AS IS" BASIS, 12 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 // See the License for the specific language governing permissions and 14 // limitations under the License. 15 // 16 17 #ifndef GRPC_SRC_CORE_LOAD_BALANCING_HEALTH_CHECK_CLIENT_H 18 #define GRPC_SRC_CORE_LOAD_BALANCING_HEALTH_CHECK_CLIENT_H 19 20 #include <grpc/support/port_platform.h> 21 22 #include <memory> 23 24 #include "src/core/lib/channel/channel_args.h" 25 #include "src/core/lib/gprpp/work_serializer.h" 26 #include "src/core/load_balancing/subchannel_interface.h" 27 28 namespace grpc_core { 29 30 // Interface for LB policies to access health check data from a subchannel. 31 // The data is reported from via a Health.Watch stream established on the 32 // subchannel whenever an LB policy registers a watcher. 33 // 34 // To use this, an LB policy will implement its own subclass of 35 // SubchannelInterface::ConnectivityStateWatcherInterface, which will 36 // receive connectivity state updates with health check status taken 37 // into account. It will then register that watcher with the subchannel 38 // like this: 39 // subchannel->AddDataWatcher( 40 // MakeHealthCheckWatcher( 41 // work_serializer(), channel_args, 42 // std::make_unique<MyConnectivityStateWatcherSubclass>(...))); 43 44 std::unique_ptr<SubchannelInterface::DataWatcherInterface> 45 MakeHealthCheckWatcher( 46 std::shared_ptr<WorkSerializer> work_serializer, const ChannelArgs& args, 47 std::unique_ptr<SubchannelInterface::ConnectivityStateWatcherInterface> 48 watcher); 49 50 } // namespace grpc_core 51 52 #endif // GRPC_SRC_CORE_LOAD_BALANCING_HEALTH_CHECK_CLIENT_H 53