gRPC结合vcpkg在x64-windows平台visual studio2019 cmake工程里面的应用-Toy模板网

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这里我们运用vcpkg去下载安装gRPC，进入vcpkg目录后，执行命令：.\vcpkg.exe install grpc:x64-windows

grpc在vcpkg里面安装完成后，我们就来使用grpc做一个简单的例子。

gRPC顾名思义，就是google的RPC方案，基于protobuf数据传输，其中proto文件的定义约定了服务器端和客户端的服务接口协议。

这里我们就用加法和乘法作为服务器端提供的服务，让客户端去调用(RPC)，我们建立三个文件夹CPP_Server, CPP_Client, proto 来分别存储服务器端代码，客户端代码，以及proto文件。项目配置选用cmakelist.txt和cmake来管理。

1. 服务器端和客户端的proto定义(calculation.proto文件)：

syntax = "proto3";
package data_handler;

service CalculationInterface{
// Add operation
rpc Add(AddRequest) returns (AddReply){}
// Multiply operation
rpc Multiply(MultiplyRequest) returns (MultiplyReply){}
}

message AddReply{
int32 result = 1;
}

message AddRequest{
int32 param1 = 1;
int32 param2 = 2;
}

message MultiplyReply{
int32 result = 1;
}

message MultiplyRequest{
int32 param1 = 1;
int32 param2 = 2;
}

2. 服务器端代码

在服务器端，我们要在cmakelist里面进行proto文件的解析执行成相应的.pb.cc，.pb.h，.grpc.pb.cc，.grpc.pb.h文件，同时对项目文件的配置。

那么我们必然要先找到grpc, protobuf库和执行文件。这时候就需要用到vcpkg这套包管理器，

而下面这句话就是让vcpkg的包管理起作用的关键：

set(CMAKE_TOOLCHAIN_FILE "$ENV{VCPKG_ROOT}/scripts/buildsystems/vcpkg.cmake" CACHE STRING "Vcpkg toolchain file")

注意这句话一定要在定义project名字之前，本例子是：project(CalculationInGrpcServer)

这样子后面的find_package, find_program， target_link_libraries等都会去vckpg里面找到。

cmake_minimum_required(VERSION 3.20)

# Note: 8 target(s) were omitted.

message("--------" $ENV{VCPKG_ROOT})

set(CMAKE_TOOLCHAIN_FILE "$ENV{VCPKG_ROOT}/scripts/buildsystems/vcpkg.cmake" CACHE STRING "Vcpkg toolchain file")
project(CalculationInGrpcServer)

set(_GRPC_GRPCPP gRPC::grpc++)
set(_PROTOBUF_LIBPROTOBUF protobuf::libprotobuf)
set(_REFLECTION gRPC::grpc++_reflection)

set(_PROTOBUF_LIBPROTOBUF_D libprotobufd)
find_package(gRPC CONFIG REQUIRED)
find_program(_PROTOBUF_PROTOC protoc REQUIRED)
find_program(_GRPC_CPP_PLUGIN_EXECUTABLE grpc_cpp_plugin REQUIRED)

# Generated proto sources
get_filename_component(proto "../proto/calculation.proto" ABSOLUTE)
get_filename_component(proto_name "../proto/calculation.proto" NAME_WE)
get_filename_component(proto_path "${proto}" PATH)

set(proto_srcs "${proto_path}/${proto_name}.pb.cc")
set(proto_hdrs "${proto_path}/${proto_name}.pb.h")
set(grpc_srcs "${proto_path}/${proto_name}.grpc.pb.cc")
set(grpc_hdrs "${proto_path}/${proto_name}.grpc.pb.h")
message("------------------------------------------------")
message(${_PROTOBUF_PROTOC})
message(${_GRPC_CPP_PLUGIN_EXECUTABLE})
message(${proto_path})

message("-------------------------------------------------")
add_custom_command(
OUTPUT "${proto_srcs}" "${proto_hdrs}" "${grpc_srcs}" "${grpc_hdrs}"
COMMAND ${_PROTOBUF_PROTOC}
ARGS --grpc_out "${proto_path}"
--cpp_out "${proto_path}"
-I "${proto_path}"
--plugin=protoc-gen-grpc="${_GRPC_CPP_PLUGIN_EXECUTABLE}"
"${proto}"
DEPENDS "${proto}")

# Include generated *.pb.h files
include_directories(
"${proto_path}"
)

file(GLOB PUBLIC_HEADER ${CMAKE_CURRENT_BINARY_DIR}/*.h
${PROJECT_SOURCE_DIR}/../proto/*.h)

add_executable(${PROJECT_NAME} CalculationServer.cc ${proto_srcs} ${grpc_srcs})
target_link_libraries(${PROJECT_NAME} PRIVATE gRPC::gpr gRPC::upb gRPC::grpc gRPC::grpc++)

message("protobuf libs are:")
message(${_PROTOBUF_LIBPROTOBUF_D})

在我们的服务器端代码里面着重用到的是::data_handler::CalculationInterface::Service，这个是proto解释器帮我们对proto文件解析成cc文件后，里面的一个Service接口，我们代码里面最主要是去实现这个接口，来看看吧：


#include <grpcpp/grpcpp.h>
#include <grpcpp/security/server_credentials.h>
#include <grpcpp/server.h>
#include <grpcpp/server_builder.h>
#include <grpcpp/server_context.h>

#include <calculation.grpc.pb.h>
#include <calculation.pb.h>
#include <thread>

using grpc::Server;
using grpc::ServerBuilder;
using ::grpc::ServerContext;
using grpc::ServerReader;
using grpc::ServerReaderWriter;
using grpc::ServerWriter;
using grpc::Status;

class CalculationInGrpcServerImpl final
    : public ::data_handler::CalculationInterface::Service {
public:
  virtual ~CalculationInGrpcServerImpl(){};

  // Add operation
  ::grpc::Status Add(::grpc::ServerContext* context,
                             const ::data_handler::AddRequest* request,
                             ::data_handler::AddReply* response) override;
  // Multiply operation
  ::grpc::Status Multiply(
      ::grpc::ServerContext* context,
      const ::data_handler::MultiplyRequest* request,
      ::data_handler::MultiplyReply* response) override;
};

::grpc::Status CalculationInGrpcServerImpl::Add(
    ::grpc::ServerContext* context,
    const ::data_handler::AddRequest* request,
    ::data_handler::AddReply* response) {
  if (!context || !request || !response) {
    return ::grpc::Status::CANCELLED;
  }
  int32_t a = request->param1();
  int32_t b = request->param2();
  int32_t result = a + b;
  response->set_result(result);
  std::cout << "Add operation: " << a << " + " << b << std::endl;
  std::cout << "The result is: " << result << std::endl;
  return ::grpc::Status::OK;
}

::grpc::Status CalculationInGrpcServerImpl::Multiply(
    ::grpc::ServerContext* context,
    const ::data_handler::MultiplyRequest* request,
    ::data_handler::MultiplyReply* response) {
  if (!context || !request || !response) {
    return ::grpc::Status::CANCELLED;
  }
  int32_t a = request->param1();
  int32_t b = request->param2();
  int32_t result = a * b;
  response->set_result(result);
  std::cout << "Multiply operation: " << a << " * " << b << std::endl;
  std::cout << "The result is: " << result << std::endl;
  return ::grpc::Status::OK;
}

// define the gRPC server
std::unique_ptr<Server> server_ptr;
CalculationInGrpcServerImpl service;

void RunServer(const std::string& server_address) {
  ServerBuilder builder;
  builder.AddListeningPort(server_address, grpc::InsecureServerCredentials());
  builder.RegisterService(&service);

  server_ptr = builder.BuildAndStart();
  std::cout << "Server(" << server_address << ") is listening on ..." << std::endl;
  std::cout << "Press 'q' to exit the server" << std::endl;

  server_ptr->Wait();
}

int main() { 

    std::string server_address("0.0.0.0:50051");
    std::thread server_thread(RunServer, server_address);

    bool running = true;
    while (running) {
      char c = getchar();
      if (c == '\n' || c == EOF) continue;
      if (c == 'q') {
        // reset running flag and shutdown server
        running = false;
        server_ptr->Shutdown();
      }
    }
    server_thread.join();
    return 0; 


}

大家有可能看到了main函数，本人偷懒，将其一起写在一个文件里了，最好还是将main函数实现放到另外的文件。当然我们重点是将grpc的运用，大家可以借鉴一下里面server是怎样绑定IP和port口，运行起来server的。

生成一下，看看是不是和预想的一样啊？

3. 客户端代码

客户端代码主要是调用服务器端的接口，就是上面写的接口，grpc通过一个stub代理来实现，这样我们就象调用本地的函数一样去远程调用函数接口了，从而达到访问服务的目的。

客户端的cmakelist.txt和服务器端的有点类似，我贴出来，大家看看就行：

cmake_minimum_required(VERSION 3.20)

# Note: 8 target(s) were omitted.

message("--------" $ENV{VCPKG_ROOT})

set(CMAKE_TOOLCHAIN_FILE "$ENV{VCPKG_ROOT}/scripts/buildsystems/vcpkg.cmake" CACHE STRING "Vcpkg toolchain file")
project(CalculationInGrpcClient)

set(_GRPC_GRPCPP gRPC::grpc++)
set(_PROTOBUF_LIBPROTOBUF protobuf::libprotobuf)
set(_REFLECTION gRPC::grpc++_reflection)

set(_PROTOBUF_LIBPROTOBUF_D libprotobufd)
find_package(gRPC CONFIG REQUIRED)
find_program(_PROTOBUF_PROTOC protoc REQUIRED)
find_program(_GRPC_CPP_PLUGIN_EXECUTABLE grpc_cpp_plugin REQUIRED)

# Generated proto sources
get_filename_component(proto "../proto/calculation.proto" ABSOLUTE)
get_filename_component(proto_name "../proto/calculation.proto" NAME_WE)
get_filename_component(proto_path "${proto}" PATH)

set(proto_srcs "${proto_path}/${proto_name}.pb.cc")
set(proto_hdrs "${proto_path}/${proto_name}.pb.h")
set(grpc_srcs "${proto_path}/${proto_name}.grpc.pb.cc")
set(grpc_hdrs "${proto_path}/${proto_name}.grpc.pb.h")
message("------------------------------------------------")
message(${_PROTOBUF_PROTOC})
message(${_GRPC_CPP_PLUGIN_EXECUTABLE})
message(${proto_path})

message("-------------------------------------------------")
add_custom_command(
OUTPUT "${proto_srcs}" "${proto_hdrs}" "${grpc_srcs}" "${grpc_hdrs}"
COMMAND ${_PROTOBUF_PROTOC}
ARGS --grpc_out "${proto_path}"
--cpp_out "${proto_path}"
-I "${proto_path}"
--plugin=protoc-gen-grpc="${_GRPC_CPP_PLUGIN_EXECUTABLE}"
"${proto}"
DEPENDS "${proto}")

# Include generated *.pb.h files
include_directories(
"${proto_path}"
)

file(GLOB PUBLIC_HEADER ${CMAKE_CURRENT_BINARY_DIR}/*.h
${PROJECT_SOURCE_DIR}/../proto/*.h)

add_executable(${PROJECT_NAME} CalculationClient.cc ${proto_srcs} ${grpc_srcs})
target_link_libraries(${PROJECT_NAME} PRIVATE gRPC::gpr gRPC::upb gRPC::grpc gRPC::grpc++)

message("protobuf libs are:")
message(${_PROTOBUF_LIBPROTOBUF_D})

下面就是要介绍客户端的代码模块了，我这边简单封装了一个客户端类去调用服务，代码如下，

大家看看简单的request/reply调用方式。


#include <grpcpp/grpcpp.h>
#include <grpcpp/security/server_credentials.h>
#include <grpcpp/server.h>
#include <grpcpp/server_builder.h>
#include <grpcpp/server_context.h>

#include <calculation.grpc.pb.h>
#include <calculation.pb.h>
#include <thread>

using grpc::Server;
using grpc::ServerBuilder;
using ::grpc::ServerContext;
using grpc::ServerReader;
using grpc::ServerReaderWriter;
using grpc::ServerWriter;
using grpc::Status;

class CalculationInGrpcClient final {
public:
    CalculationInGrpcClient(CalculationInGrpcClient& param) = delete;
    CalculationInGrpcClient& operator=(CalculationInGrpcClient& param) = delete;

    CalculationInGrpcClient(std::shared_ptr<grpc::Channel> channelPtr);
    ~CalculationInGrpcClient(){};

    bool RequestAddOperation(const int32_t a, const int32_t b, int32_t& result);
    bool RequestMultiplyOperation(const int32_t a, const int32_t b, int32_t& result);

private:

    std::unique_ptr<data_handler::CalculationInterface::Stub> mStub;
};

CalculationInGrpcClient::CalculationInGrpcClient(
    std::shared_ptr<grpc::Channel> channel)
    : mStub(data_handler::CalculationInterface::NewStub(channel)) {}

bool CalculationInGrpcClient::RequestAddOperation(int32_t a, int32_t b,
                                                  int32_t& result) {
    grpc::Status grcpStatus;
    grpc::ClientContext context;
    data_handler::AddReply reply;
    data_handler::AddRequest request;
    request.set_param1(a);
    request.set_param2(b);
    grcpStatus = mStub->Add(&context, request, &reply);

    if (grcpStatus.error_code() == ::grpc::StatusCode::OK) {
        result = static_cast<int32_t>(reply.result());
        std::cout << "After adding operation, the result is: " 
                    << result
                    << std::endl;
        return true;
    } else {
        std::cout << "Server not running..." << std::endl;
    }
    return false;
}

bool CalculationInGrpcClient::RequestMultiplyOperation(int32_t a, int32_t b,
                                                       int32_t& result) {
    grpc::Status grcpStatus;
    grpc::ClientContext context;
    data_handler::MultiplyReply reply;
    data_handler::MultiplyRequest request;
    request.set_param1(a);
    request.set_param2(b);
    grcpStatus = mStub->Multiply(&context, request, &reply);

    if (grcpStatus.error_code() == ::grpc::StatusCode::OK) {
        result = static_cast<int32_t>(reply.result());
        std::cout << "After Multiplication operation, the result is: " 
                    << result
                    << std::endl;
        return true;
    } else {
        std::cout << "Server not running..." << std::endl;
    }
    return false;
}

void showHelp() {
    std::cout << "Calculation starts : \r\n\
            Press 'q' to exit the calculator. \r\n\
            "
            << std::endl;
}

bool FindParamters(const std::string& src, const char operation, int32_t& left, int32_t& right) {
  auto it = src.find(operation);
  if (it != std::string::npos) {
    std::string leftParam = src.substr(0, it);
    std::string rightParam = src.substr(it + 1, src.length() - it - 1);
    left = atoi(leftParam.c_str());
    right = atoi(rightParam.c_str());
    return true;
  }
  return false;
}

int main() { 

    showHelp();
    auto grpcChannel = grpc::CreateChannel("127.0.0.1:50051",
                                         grpc::InsecureChannelCredentials());
    if (!grpcChannel) {
        printf("Failed to create gRPC channel\n");
        return 0;
    }

    std::unique_ptr<CalculationInGrpcClient> clientPtr =
        std::make_unique<CalculationInGrpcClient>(grpcChannel);

    bool running = true;
    while (running) {
        std::string strTmp;
        std::getline(std::cin, strTmp);
        int32_t a = 0;
        int32_t b = 0;
        int32_t result = 0;
        if (FindParamters(strTmp, '+', a, b)) {
            if (clientPtr) {
            clientPtr->RequestAddOperation(a, b, result);
            }
        } else if (FindParamters(strTmp, '*', a, b)) {
            if (clientPtr) {
            clientPtr->RequestMultiplyOperation(a, b, result);
            }
        } else {
            // reserve
        }

        if (strTmp.find('q') != std::string::npos) {
            // reset running flag and shutdown server
            running = false;
        }
    }

    return 0; 


}

代码里面的request, reply基本上是固定格式：

grpc::Status grcpStatus;
grpc::ClientContext context;
data_handler::MultiplyReply reply;
data_handler::MultiplyRequest request;
request.set_param1(a);
request.set_param2(b);
grcpStatus = mStub->Multiply(&context, request, &reply);

主要是stub去调用服务器端的接口，而前的context, request, reply都是准备工作。

grpc的createChannel绑定了服务器端的IP和port，进行服务器端和客户端通信，grpc都封装好了，固定格式调用就行。

4. 编译生成后，运行服务器端后，在运行客户端

gRPC结合vcpkg在x64-windows平台visual studio2019 cmake工程里面的应用