1 // Copyright 2023 gRPC authors.
2 //
3 // Licensed under the Apache License, Version 2.0 (the "License");
4 // you may not use this file except in compliance with the License.
5 // You may obtain a copy of the License at
6 //
7 // http://www.apache.org/licenses/LICENSE-2.0
8 //
9 // Unless required by applicable law or agreed to in writing, software
10 // distributed under the License is distributed on an "AS IS" BASIS,
11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 // See the License for the specific language governing permissions and
13 // limitations under the License.
14
15 #include <iostream>
16 #include <memory>
17 #include <string>
18 #include <unordered_set>
19
20 #include "absl/flags/flag.h"
21 #include "absl/flags/parse.h"
22 #include "absl/strings/str_format.h"
23 #include "absl/synchronization/mutex.h"
24
25 #include <grpcpp/grpcpp.h>
26 #include <grpcpp/health_check_service_interface.h>
27
28 #ifdef BAZEL_BUILD
29 #include "examples/protos/helloworld.grpc.pb.h"
30 #else
31 #include "helloworld.grpc.pb.h"
32 #endif
33
34 ABSL_FLAG(uint16_t, port, 50051, "Server port for the service");
35
36 using grpc::ByteBuffer;
37 using grpc::CallbackGenericService;
38 using grpc::CallbackServerContext;
39 using grpc::GenericCallbackServerContext;
40 using grpc::ProtoBufferReader;
41 using grpc::ProtoBufferWriter;
42 using grpc::Server;
43 using grpc::ServerBuilder;
44 using grpc::ServerGenericBidiReactor;
45 using grpc::Status;
46 using grpc::StatusCode;
47 using helloworld::HelloReply;
48 using helloworld::HelloRequest;
49
50 // Logic and data behind the server's behavior.
51 class GreeterServiceImpl final : public CallbackGenericService {
CreateReactor(GenericCallbackServerContext * context)52 ServerGenericBidiReactor* CreateReactor(
53 GenericCallbackServerContext* context) override {
54 if (context->method() == "/helloworld.Greeter/SayHello") {
55 // Let the SayHello reactor handle this now on.
56 return new SayHelloReactor();
57 } else {
58 // Forward this to the implementation of the base calss returning
59 // UNIMPLEMENTED.
60 return CallbackGenericService::CreateReactor(context);
61 }
62 }
63
64 class SayHelloReactor : public ServerGenericBidiReactor {
65 public:
SayHelloReactor()66 SayHelloReactor() { StartRead(&request_); }
67
68 private:
OnSayHello(const HelloRequest & request,HelloReply * reply)69 Status OnSayHello(const HelloRequest& request, HelloReply* reply) {
70 if (request.name() == "") {
71 return Status(StatusCode::INVALID_ARGUMENT, "name is not specified");
72 }
73 reply->set_message(absl::StrFormat("Hello %s", request.name()));
74 return Status::OK;
75 }
76
OnDone()77 void OnDone() override { delete this; }
OnReadDone(bool ok)78 void OnReadDone(bool ok) override {
79 if (!ok) {
80 return;
81 }
82 Status result;
83 // Deserialize a request message
84 HelloRequest request;
85 result = grpc::GenericDeserialize<ProtoBufferReader, HelloRequest>(
86 &request_, &request);
87 if (!result.ok()) {
88 Finish(result);
89 return;
90 }
91 // Call the SayHello handler
92 HelloReply reply;
93 result = OnSayHello(request, &reply);
94 if (!result.ok()) {
95 Finish(result);
96 return;
97 }
98 // Serialize a reply message
99 bool own_buffer;
100 result = grpc::GenericSerialize<ProtoBufferWriter, HelloReply>(
101 reply, &response_, &own_buffer);
102 if (!result.ok()) {
103 Finish(result);
104 return;
105 }
106 StartWrite(&response_);
107 }
OnWriteDone(bool ok)108 void OnWriteDone(bool ok) override {
109 Finish(ok ? Status::OK
110 : Status(StatusCode::UNKNOWN, "Unexpected failure"));
111 }
112 ByteBuffer request_;
113 ByteBuffer response_;
114 };
115
116 private:
117 absl::Mutex mu_;
118 };
119
RunServer(uint16_t port)120 void RunServer(uint16_t port) {
121 std::string server_address = absl::StrFormat("0.0.0.0:%d", port);
122 GreeterServiceImpl service;
123 grpc::EnableDefaultHealthCheckService(true);
124 ServerBuilder builder;
125 // Listen on the given address without any authentication mechanism.
126 builder.AddListeningPort(server_address, grpc::InsecureServerCredentials());
127 // Register "service" as the instance through which we'll communicate with
128 // clients. In this case it corresponds to an *synchronous* service.
129 builder.RegisterCallbackGenericService(&service);
130 // Finally assemble the server.
131 std::unique_ptr<Server> server(builder.BuildAndStart());
132 std::cout << "Server listening on " << server_address << std::endl;
133
134 // Wait for the server to shutdown. Note that some other thread must be
135 // responsible for shutting down the server for this call to ever return.
136 server->Wait();
137 }
138
main(int argc,char ** argv)139 int main(int argc, char** argv) {
140 absl::ParseCommandLine(argc, argv);
141 RunServer(absl::GetFlag(FLAGS_port));
142 return 0;
143 }
144