grpc+protobuf 的C++ service 实例解析

来源：互联网发布：数据库用来做什么编辑：程序博客网时间：2024/05/18 00:51

这篇文章将会简单的描述一下grpc+protobuf 的C++ service的搭建过程，告诉读者在linux系统下怎样实现一个service接口的流程。

一、.proto文件的

实现一个简单的helloworld回显功能，首先需要一个.proto文件，我将它命名为example.proto，文件内容如下：

syntax = "proto3";message SearchRequest{string Request = 1;}message SearchResponse{string Response = 2;}service SearchService {  rpc Search (SearchRequest) returns (SearchResponse);}

二、自动生成代码

使用example.proto文件自动生成grpc和protobuf的代码

protoc --cpp_out=./ examples.protoprotoc --grpc_out=./ --plugin=protoc-gen-grpc=/usr/local/bin/grpc_cpp_plugin examples.proto

这两个命令将会生成四个文件，examples.grpc.pb.cc、examples.grpc.pb.h、examples.pb.cc、examples.pb.h。

三、服务器代码

#include <iostream>#include <memory>#include <string>#include <grpc++/grpc++.h>#include <grpc/grpc.h>#include <grpc++/server.h>#include <grpc++/server_builder.h>#include <grpc++/server_context.h>#include "examples.grpc.pb.h"using grpc::Server;using grpc::ServerBuilder;using grpc::ServerContext;using grpc::Status;class SearchRequestImpl final : public SearchService::Service {  Status Search(ServerContext* context, const SearchRequest* request,                  SearchResponse* reply) override {    std::string prefix("Hello ");    reply->set_response(prefix + request->request());    return Status::OK;  }};void RunServer() {  std::string server_address("0.0.0.0:50051");  SearchRequestImpl service;  ServerBuilder builder;  builder.AddListeningPort(server_address, grpc::InsecureServerCredentials());  builder.RegisterService(&service);  std::unique_ptr<Server> server(builder.BuildAndStart());  std::cout << "Server listening on " << server_address << std::endl;  server->Wait();}int main(int argc, char** argv) {  RunServer();  return 0;}

四、客户端代码

#include <iostream>#include <memory>#include <string>#include <grpc++/grpc++.h>#include <grpc/support/log.h>#include "examples.grpc.pb.h"using grpc::Channel;using grpc::ClientAsyncResponseReader;using grpc::ClientContext;using grpc::CompletionQueue;using grpc::Status;class ExampleClient { public:  explicit ExampleClient(std::shared_ptr<Channel> channel)      : stub_(SearchService::NewStub(channel)) {}   std::string Search(const std::string& user) {     SearchRequest request;    request.set_request(user);     SearchResponse reply;       ClientContext context;    CompletionQueue cq;    Status status;    std::unique_ptr<ClientAsyncResponseReader<SearchResponse> > rpc(        stub_->AsyncSearch(&context, request, &cq));    rpc->Finish(&reply, &status, (void*)1);    void* got_tag;    bool ok = false;      GPR_ASSERT(cq.Next(&got_tag, &ok));       GPR_ASSERT(got_tag == (void*)1);      GPR_ASSERT(ok);    if (status.ok()) {      return reply.response();    } else {      return "RPC failed";    }  } private:   std::unique_ptr<SearchService::Stub> stub_;};int main(int argc, char** argv) {  ExampleClient client(grpc::CreateChannel(      "localhost:50051", grpc::InsecureChannelCredentials()));  std::string user("world");  std::string reply = client.Search(user);  // The actual RPC call!  std::cout << "client received: " << reply << std::endl;  return 0;}

五、Makefile文件

subdir = ./export PKG_CONFIG_PATH=/usr/local/lib/pkgconfigSOURCES = $(wildcard $(subdir)*.cc)SRCOBJS = $(patsubst %.cc,%.o,$(SOURCES))CC = g++%.o:%.cc$(CC) -std=c++11 -I/usr/local/include -pthread -c $< -o $@all: client serverclient:examples.grpc.pb.o examples.pb.o examples_client.o$(CC) $^ -L/usr/local/lib `pkg-config --libs grpc++ grpc` -Wl,--no-as-needed -lgrpc++_reflection -Wl,--as-needed -lprotobuf -lpthread -ldl -lssl -o $@server:examples.grpc.pb.o examples.pb.o examples_server.o$(CC) $^ -L/usr/local/lib `pkg-config --libs grpc++ grpc` -Wl,--no-as-needed -lgrpc++_reflection -Wl,--as-needed -lprotobuf -lpthread -ldl -lssl -o $@#chmod 777 $@clean:sudo rm *.o

六、运行

运行./server启动service，在另一个端口运行./client 打印出：client received: Hello world表示两边已通，grpc+protobuf 搭建完成。

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