1 /*
2 *
3 * Copyright 2021 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 #include <iostream>
20 #include <memory>
21 #include <string>
22
23 #include "absl/flags/flag.h"
24 #include "absl/flags/parse.h"
25
26 #include <grpcpp/grpcpp.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(std::string, target, "xds:///helloworld:50051", "Target string");
35 ABSL_FLAG(bool, secure, true, "Secure mode");
36
37 using grpc::Channel;
38 using grpc::ClientContext;
39 using grpc::Status;
40 using helloworld::Greeter;
41 using helloworld::HelloReply;
42 using helloworld::HelloRequest;
43
44 class GreeterClient {
45 public:
GreeterClient(std::shared_ptr<Channel> channel)46 GreeterClient(std::shared_ptr<Channel> channel)
47 : stub_(Greeter::NewStub(channel)) {}
48
49 // Assembles the client's payload, sends it and presents the response back
50 // from the server.
SayHello(const std::string & user)51 std::string SayHello(const std::string& user) {
52 // Data we are sending to the server.
53 HelloRequest request;
54 request.set_name(user);
55
56 // Container for the data we expect from the server.
57 HelloReply reply;
58
59 // Context for the client. It could be used to convey extra information to
60 // the server and/or tweak certain RPC behaviors.
61 ClientContext context;
62
63 // The actual RPC.
64 Status status = stub_->SayHello(&context, request, &reply);
65
66 // Act upon its status.
67 if (status.ok()) {
68 return reply.message();
69 } else {
70 std::cout << status.error_code() << ": " << status.error_message()
71 << std::endl;
72 return "RPC failed";
73 }
74 }
75
76 private:
77 std::unique_ptr<Greeter::Stub> stub_;
78 };
79
main(int argc,char ** argv)80 int main(int argc, char** argv) {
81 absl::ParseCommandLine(argc, argv);
82 GreeterClient greeter(grpc::CreateChannel(
83 absl::GetFlag(FLAGS_target),
84 absl::GetFlag(FLAGS_secure)
85 ? grpc::XdsCredentials(grpc::InsecureChannelCredentials())
86 : grpc::InsecureChannelCredentials()));
87 std::string user("world");
88 std::string reply = greeter.SayHello(user);
89 std::cout << "Greeter received: " << reply << std::endl;
90
91 return 0;
92 }
93