1 /* 2 * Copyright 2014 Google Inc. All rights reserved. 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 #include <thread> 18 19 #include <grpc++/grpc++.h> 20 21 #include "monster_test_generated.h" 22 #include "monster_test.grpc.fb.h" 23 24 using namespace MyGame::Example; 25 26 // The callback implementation of our server, that derives from the generated 27 // code. It implements all rpcs specified in the FlatBuffers schema. 28 class ServiceImpl final : public MyGame::Example::MonsterStorage::Service { 29 virtual ::grpc::Status Store(::grpc::ServerContext* context, 30 const flatbuffers::BufferRef<Monster> *request, 31 flatbuffers::BufferRef<Stat> *response) 32 override { 33 // Create a response from the incoming request name. 34 fbb_.Clear(); 35 auto stat_offset = CreateStat(fbb_, fbb_.CreateString("Hello, " + 36 request->GetRoot()->name()->str())); 37 fbb_.Finish(stat_offset); 38 // Since we keep reusing the same FlatBufferBuilder, the memory it owns 39 // remains valid until the next call (this BufferRef doesn't own the 40 // memory it points to). 41 *response = flatbuffers::BufferRef<Stat>(fbb_.GetBufferPointer(), 42 fbb_.GetSize()); 43 return grpc::Status::OK; 44 } 45 virtual ::grpc::Status Retrieve(::grpc::ServerContext *context, 46 const flatbuffers::BufferRef<Stat> *request, 47 ::grpc::ServerWriter< flatbuffers::BufferRef<Monster>>* writer) 48 override { 49 assert(false); // We're not actually using this RPC. 50 return grpc::Status::CANCELLED; 51 } 52 53 private: 54 flatbuffers::FlatBufferBuilder fbb_; 55 }; 56 57 // Track the server instance, so we can terminate it later. 58 grpc::Server *server_instance = nullptr; 59 // Mutex to protec this variable. 60 std::mutex wait_for_server; 61 std::condition_variable server_instance_cv; 62 63 // This function implements the server thread. 64 void RunServer() { 65 auto server_address = "0.0.0.0:50051"; 66 // Callback interface we implemented above. 67 ServiceImpl service; 68 grpc::ServerBuilder builder; 69 builder.AddListeningPort(server_address, grpc::InsecureServerCredentials()); 70 builder.RegisterService(&service); 71 72 // Start the server. Lock to change the variable we're changing. 73 wait_for_server.lock(); 74 server_instance = builder.BuildAndStart().release(); 75 wait_for_server.unlock(); 76 server_instance_cv.notify_one(); 77 78 std::cout << "Server listening on " << server_address << std::endl; 79 // This will block the thread and serve requests. 80 server_instance->Wait(); 81 } 82 83 int main(int /*argc*/, const char * /*argv*/[]) { 84 // Launch server. 85 std::thread server_thread(RunServer); 86 87 // wait for server to spin up. 88 std::unique_lock<std::mutex> lock(wait_for_server); 89 while (!server_instance) server_instance_cv.wait(lock); 90 91 // Now connect the client. 92 auto channel = grpc::CreateChannel("localhost:50051", 93 grpc::InsecureChannelCredentials()); 94 auto stub = MyGame::Example::MonsterStorage::NewStub(channel); 95 96 grpc::ClientContext context; 97 98 // Build a request with the name set. 99 flatbuffers::FlatBufferBuilder fbb; 100 auto monster_offset = CreateMonster(fbb, 0, 0, 0, fbb.CreateString("Fred")); 101 fbb.Finish(monster_offset); 102 auto request = flatbuffers::BufferRef<Monster>(fbb.GetBufferPointer(), 103 fbb.GetSize()); 104 flatbuffers::BufferRef<Stat> response; 105 106 // The actual RPC. 107 auto status = stub->Store(&context, request, &response); 108 109 if (status.ok()) { 110 auto resp = response.GetRoot()->id(); 111 std::cout << "RPC response: " << resp->str() << std::endl; 112 } else { 113 std::cout << "RPC failed" << std::endl; 114 } 115 116 server_instance->Shutdown(); 117 118 server_thread.join(); 119 120 delete server_instance; 121 122 return 0; 123 } 124 125
