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 {
Store(::grpc::ServerContext * context,const flatbuffers::BufferRef<Monster> * request,flatbuffers::BufferRef<Stat> * response)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 }
Retrieve(::grpc::ServerContext * context,const flatbuffers::BufferRef<Stat> * request,::grpc::ServerWriter<flatbuffers::BufferRef<Monster>> * writer)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.
RunServer()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
main(int,const char * [])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