1 // 2 // 3 // Copyright 2016 gRPC authors. 4 // 5 // Licensed under the Apache License, Version 2.0 (the "License"); 6 // you may not use this file except in compliance with the License. 7 // You may obtain a copy of the License at 8 // 9 // http://www.apache.org/licenses/LICENSE-2.0 10 // 11 // Unless required by applicable law or agreed to in writing, software 12 // distributed under the License is distributed on an "AS IS" BASIS, 13 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 // See the License for the specific language governing permissions and 15 // limitations under the License. 16 // 17 // 18 19 #ifndef GRPC_SRC_CORE_LIB_SURFACE_LAME_CLIENT_H 20 #define GRPC_SRC_CORE_LIB_SURFACE_LAME_CLIENT_H 21 22 #include <grpc/grpc.h> 23 #include <grpc/support/port_platform.h> 24 25 #include <memory> 26 27 #include "absl/base/thread_annotations.h" 28 #include "absl/status/status.h" 29 #include "absl/status/statusor.h" 30 #include "src/core/lib/channel/channel_args.h" 31 #include "src/core/lib/channel/channel_fwd.h" 32 #include "src/core/lib/channel/promise_based_filter.h" 33 #include "src/core/lib/iomgr/error.h" 34 #include "src/core/lib/promise/arena_promise.h" 35 #include "src/core/lib/transport/connectivity_state.h" 36 #include "src/core/lib/transport/transport.h" 37 #include "src/core/util/sync.h" 38 39 #define GRPC_ARG_LAME_FILTER_ERROR "grpc.lame_filter_error" 40 41 namespace grpc_core { 42 43 // This filter becomes the entire channel stack for a channel that fails to be 44 // created. Every call returns failure. 45 class LameClientFilter : public ChannelFilter { 46 public: 47 static const grpc_channel_filter kFilter; 48 TypeName()49 static absl::string_view TypeName() { return "lame-client"; } 50 51 explicit LameClientFilter(absl::Status error); 52 53 static absl::StatusOr<std::unique_ptr<LameClientFilter>> Create( 54 const ChannelArgs& args, ChannelFilter::Args filter_args); 55 ArenaPromise<ServerMetadataHandle> MakeCallPromise( 56 CallArgs call_args, NextPromiseFactory next_promise_factory) override; 57 bool StartTransportOp(grpc_transport_op*) override; 58 bool GetChannelInfo(const grpc_channel_info*) override; 59 60 private: 61 absl::Status error_; 62 Mutex mu_; 63 ConnectivityStateTracker state_tracker_ ABSL_GUARDED_BY(mu_); 64 }; 65 66 extern const grpc_arg_pointer_vtable kLameFilterErrorArgVtable; 67 68 grpc_arg MakeLameClientErrorArg(grpc_error_handle* error); 69 70 } // namespace grpc_core 71 72 #endif // GRPC_SRC_CORE_LIB_SURFACE_LAME_CLIENT_H 73