gRPC的安装及使用
本章我们简单介绍一下gRPC的安装及使用
1. gRPC的安装
1) 安装protobuf
关于protobuf的安装，我们前面介绍过，这里不再赘述。
2） 安装依赖库libcares
在安装gRPC时我们发现需要依赖libcares库，但是gRPC其本身的编译脚本不能很好的安装该库，这里我们手动安装：
# wget https://c-ares.haxx.se/download/c-ares-1.15.0.tar.gz # tar -zxvf c-ares-1.15.0.tar.gz # cd c-ares-1.15.0/ # ./configure --prefix=/usr/local/cares # make # make install # ls /usr/local/cares include lib share
3) 安装perftools
gperftools依赖于libunwind，首先执行如下命令安装：
# wget http://download.savannah.nongnu.org/releases/libunwind/libunwind-1.3.1.tar.gz # tar -zxvf libunwind-1.3.1.tar.gz # cd libunwind-1.3.1/ ./configure --prefix=/usr/local/unwind # make # make install # ls /usr/local/unwind/ include lib
接着再安装google-perfile:
# wget https://github.com/gperftools/gperftools/releases/download/gperftools-2.7/gperftools-2.7.tar.gz # tar -zxvf gperftools-2.7.tar.gz # cd gperftools-2.7/ # ./configure --prefix=/usr/local/gperftools # make # make install # ls /usr/local/gperftools/ bin include lib share
3） 安装gRPC
这里我们先下载gRPC安装软件包并解压：
# mkdir gRPC-inst # cd gRPC-inst # wget https://github.com/grpc/grpc/archive/v1.22.0.tar.gz # tar -zxvf v1.22.0.tar.gz # cd grpc-1.22.0/
由于gRPC编译安装脚本写的不是很好，在执行make run_dep_checks时会通过pkg-config来识别编译时所依赖的库是否存在，而真正在执行make时却又会识别不了，因此我们导出如下几个环境变量：
# export PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/root/bin:/usr/local/protobuf/bin/ # export PKG_CONFIG_PATH=/usr/local/protobuf/lib/pkgconfig/:/usr/local/cares/lib/pkgconfig/:/usr/local/gperftools/lib/pkgconfig/ //编译时 # export LIBRARY_PATH=$LIBRARY_PATH:/usr/local/protobuf/lib/:/usr/local/cares/lib/:/usr/local/gperftools/lib/ //编译时
修改Makefile文件，在PERFTOOLS_CHECK_CMD命令最后加上pkg-config，最后如下：
PERFTOOLS_CHECK_CMD = $(CC) $(CPPFLAGS) $(CFLAGS) -o $(TMPOUT) test/build/perftools.c -lprofiler $(LDFLAGS) `pkg-config --cflags libprofiler`然后执行如下命令检查编译环境是否有问题：
# make run_dep_checks
其实，这里我们可以不用安装perftools，检查时发现有perftools方面的错误，但都是test里面的，因此可以忽略跳过。最后接着执行如下命令进行安装：
# make # make prefix=/usr/local/grpc # make install prefix=/usr/local/grpc
2. gRPC示例
如下我们使用gRPC+protobuf实现一个回显功能。
1) 编写proto文件
如下我们实现一个回显服务器，编写echoserver.proto:
syntax = "proto3";
message EchoRequest {
string request = 1;
}
message EchoResponse {
string response = 1;
}
service EchoService {
rpc echo(EchoRequest) returns (EchoResponse);
}2) 自动生成protobuf及grpc代码
如下我们使用echoserver.proto自动生成grpc及protobuf代码：
# /usr/local/protobuf/bin/protoc --cpp_out=./ echoserver.proto # /usr/local/protobuf/bin/protoc --grpc_out=./ --plugin=protoc-gen-grpc=/usr/local/grpc/bin/grpc_cpp_plugin echoserver.proto # ls echoserver.grpc.pb.cc echoserver.grpc.pb.h echoserver.pb.cc echoserver.pb.h echoserver.proto
这两个命令将会生成如下4个文件：echoserver.pb.c(h)、echoserver.grpc.pb.c(h)
3) 编写服务器代码
如下我们编写服务器代码grpc_echo_server.cpp:
#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 "echoserver.grpc.pb.h"
using grpc::Server;
using grpc::ServerBuilder;
using grpc::ServerContext;
using grpc::Status;
class EchoServiceImpl final : public EchoService::Service{
//override echo
::grpc::Status echo(::grpc::ServerContext* context, const ::EchoRequest* request, ::EchoResponse* response){
std::string prefix("Hello ");
response->set_response(prefix + request->request());
return Status::OK;
}
};
void RunServer(){
std::string server_address("0.0.0.0:50051");
EchoServiceImpl echoservice;
ServerBuilder builder;
builder.AddListeningPort(server_address, grpc::InsecureServerCredentials());
builder.RegisterService(&echoservice);
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 0x0;
}执行如下命令进行编译：
# export PKG_CONFIG_PATH=/usr/local/cares/lib/pkgconfig/:/usr/local/protobuf/lib/pkgconfig/:/usr/local/grpc/lib/pkgconfig/ # gcc -o grpc_echo_server ./echoserver.pb.cc ./echoserver.grpc.pb.cc ./grpc_echo_server.cpp \ -std=c++11 `pkg-config --cflags --libs grpc grpc++ protobuf libcares gpr` -lstdc++ # ls echoserver.grpc.pb.cc echoserver.grpc.pb.h echoserver.pb.cc echoserver.pb.h echoserver.proto grpc_echo_server grpc_echo_server.cpp
4) 编写客户端代码
如下我们编写服务器代码grpc_echo_client.cpp:
#include <iostream>
#include <memory>
#include <string>
#include <grpc++/grpc++.h>
#include <grpc/support/log.h>
#include "echoserver.grpc.pb.h"
using grpc::Channel;
using grpc::ClientAsyncResponseReader;
using grpc::ClientContext;
using grpc::CompletionQueue;
using grpc::Status;
class EchoClient {
public:
explicit EchoClient(std::shared_ptr<Channel> channel)
: stub_(EchoService::NewStub(channel)) {}
std::string echo(const std::string& msg) {
EchoRequest request;
request.set_request(msg);
EchoResponse reply;
ClientContext context;
CompletionQueue cq;
Status status;
std::unique_ptr<ClientAsyncResponseReader<EchoResponse> > rpc(
stub_->Asyncecho(&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<EchoService::Stub> stub_;
};
int main(int argc, char *argv[]) {
EchoClient client(grpc::CreateChannel(
"localhost:50051", grpc::InsecureChannelCredentials()));
std::string msg("world");
std::string reply = client.echo(msg); // The actual RPC call!
std::cout << "client received: " << reply << std::endl;
return 0;
} 执行如下命令进行编译：
# export PKG_CONFIG_PATH=/usr/local/cares/lib/pkgconfig/:/usr/local/protobuf/lib/pkgconfig/:/usr/local/grpc/lib/pkgconfig/ # gcc -o grpc_echo_client ./echoserver.pb.cc ./echoserver.grpc.pb.cc ./grpc_echo_client.cpp \ -std=c++11 `pkg-config --cflags --libs grpc grpc++ protobuf libcares gpr` -lstdc++ # ls echoserver.grpc.pb.cc echoserver.pb.cc echoserver.proto grpc_echo_client.cpp grpc_echo_server.cpp echoserver.grpc.pb.h echoserver.pb.h grpc_echo_client grpc_echo_server
5) 运行测试
服务端运行：
# export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/usr/local/protobuf/lib/:/usr/local/grpc/lib/:/usr/local/cares/lib/ # ./grpc_echo_server Server listening on 0.0.0.0:50051
客户端运行：
# export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/usr/local/protobuf/lib/:/usr/local/grpc/lib/:/usr/local/cares/lib/ # ./grpc_echo_client client received: Hello world
[参看]:
