Mac gRPC for C++

#0 原始碼

https://github.com/Coxhuang/FKCpp/tree/master/gRPCDemo

#1 環境

C++14
Python 3.8
macOS 10.5.15
cmake 3.18.2 
proto 3
Clion

#2 安裝

略

#3 開始

#3.1 說明

• 使用前需要安裝gRPC
• C++實現gRPC服務端(CMake編譯)
• Python/C++實現gRPC客戶端

#3.2 目錄結構

.
├── CMakeLists.txt
├── build
│   ├── CMakeCache.txt
│   ├── CMakeFiles
│   ├── Makefile
│   ├── cmake_install.cmake
│   ├── hello_bin
│   └── libhellolibrary.a
├── client.py
├── client_cpp
│   ├── CMakeLists.txt
│   ├── build
│   └── main.cpp
├── main.cpp
├── protos
│   ├── helloworld.grpc.pb.cc
│   ├── helloworld.grpc.pb.h
│   ├── helloworld.pb.cc
│   ├── helloworld.pb.h
│   ├── helloworld.proto
│   ├── helloworld_pb2.py
│   └── helloworld_pb2_grpc.py
└── server_cpp
    ├── CMakeLists.txt
    ├── build
    └── main.cpp

#3.3 proto檔案

helloworld.proto

syntax = "proto3";

option java_package = "ex.grpc";

package helloworld;

message Reply {
    int32 result = 1;
}

message HelloMessage {
    int32 a = 1;
    int32 b = 2;
}

service TestServer {
    rpc hello_request (HelloMessage) returns (Reply) {}
}

生成c++和python對應的檔案

• C++

cd protos
protoc --cpp_out=. helloworld.proto
protoc --grpc_out=. --plugin=protoc-gen-grpc=`which grpc_cpp_plugin` helloworld.proto

生成: helloworld.grpc.pb.cc helloworld.grpc.pb.h helloworld.pb.cc helloworld.pb.h

• Python

cd protos
python3 -m grpc_tools.protoc -I. --python_out=. --grpc_python_out=. helloworld.proto

生成: helloworld_pb2_grpc.py helloworld_pb2.py

#3.4 gRPC服務端(C++)

main.cpp

#include <string>
#include <grpcpp/grpcpp.h>
#include "protos/helloworld.grpc.pb.h"

using grpc::Server;
using grpc::ServerBuilder;
using grpc::ServerContext;
using grpc::Status;

using helloworld::TestServer; // MathTest
using helloworld::HelloMessage; // MathRequest
using helloworld::Reply; // MathReply

class HelloServiceImplementation final : public TestServer::Service {
    Status hello_request(
            ServerContext* context,
            const HelloMessage* request,
            Reply* reply
    ) override {
        int a = request->a();
        int b = request->b();
        reply->set_result(a * b);
        return Status::OK;
    }
};

void Run() {
    std::string address("0.0.0.0:5000");
    HelloServiceImplementation service;
    ServerBuilder builder;
    builder.AddListeningPort(address, grpc::InsecureServerCredentials());
    builder.RegisterService(&service);
    std::unique_ptr<Server> server(builder.BuildAndStart());
    std::cout << "Server listening on port: " << address << std::endl;
    server->Wait();
}

int main(int argc, char** argv) {
    Run();
    return 0;
}

CMakeLists.txt

cmake_minimum_required(VERSION 3.17)

project(grpcdemo)

set(CMAKE_CXX_STANDARD 14)

find_package(Protobuf REQUIRED)

set(_PROTOBUF_LIBPROTOBUF protobuf::libprotobuf)

find_package(PkgConfig REQUIRED)
pkg_check_modules(GRPCPP REQUIRED grpc++>=1.22.0)

include_directories(
        ${GRPCPP_INCLUDE_DIRS}
        ${Protobuf_INCLUDE_DIRS}
)

link_directories(
        ${GRPCPP_LIBRARY_DIRS}
)


add_library(hellolibrary ../protos/helloworld.grpc.pb.cc ../protos/helloworld.pb.cc )

add_executable(server_bin main.cpp)

target_link_libraries(server_bin
        ${GRPCPP_LIBRARIES}
        ${_PROTOBUF_LIBPROTOBUF}
        hellolibrary
        )

#3.6 gRPC客戶端(Python/C++)

#3.6.1 Python

client.py

import grpc
from protos import helloworld_pb2
from protos import helloworld_pb2_grpc
from google.protobuf.json_format import ParseDict
import time


class HelloBusiness(object):

    def __init__(self):
        super(HelloBusiness, self).__init__()
        self.ip = "127.0.0.1"
        self.port = 5000
        self.client_init()

    def client_init(self):
        """
        gRPC客戶端初始化
        :return: None
        """

        self.channel = grpc.insecure_channel('{}:{}'.format(self.ip, self.port))
        self.client = helloworld_pb2_grpc.TestServerStub(self.channel)

        return None

    def hello_business(self, msg):
        """

        :param msg: request msg
        :return:
        """

        proto_data = helloworld_pb2.HelloMessage()  #
        ParseDict(msg, proto_data)  # 格式化msg
        response = self.client.hello_request.future(proto_data)  # 向server傳送資料
        response.add_done_callback(self.hello_callback)  # 回撥函式, 傳送資料使用非同步[future]時, 必須加回撥函式

        return response

    def hello_callback(self, future):

        print(future.result().result)
        print("callback")

class HelloWorld(HelloBusiness):

    def hello(self, *args, **kwargs):
        """

        :return: None
        """

        self.hello_business({
            "a": 1,
            "b": 2,
        })

        return None


grpc_client = HelloWorld()

if __name__ == '__main__':

    grpc_client.hello()
    time.sleep(2)

#3.6.2 C++

#include <iostream>
#include <memory>
#include <string>

#include <grpcpp/grpcpp.h>

#ifdef BAZEL_BUILD
#include "examples/protos/helloworld.grpc.pb.h"
#else
#include "../protos/helloworld.grpc.pb.h"
#endif

using grpc::Channel;
using grpc::ClientContext;
using grpc::Status;
using helloworld::TestServer; // Greeter
using helloworld::HelloMessage; // HelloRequest
using helloworld::Reply; // HelloReply


class GreeterClient {
public:

    GreeterClient(std::shared_ptr<Channel> channel):stub_(TestServer::NewStub(channel)) {}

    int say_hello(const std::string& user) {

        HelloMessage request;
        Reply reply;
        ClientContext context;

        request.set_a(21);
        request.set_b(22);

        Status status = stub_->hello_request(&context, request, &reply);

        if (status.ok()) {
            return reply.result();
        } else {
            std::cout << status.error_code() << ": " << status.error_message() << std::endl;
            return 0;
        }
    }

private:
    std::unique_ptr<TestServer::Stub> stub_;

};

int main(int argc, char** argv) {

    GreeterClient greeter(grpc::CreateChannel("127.0.0.1:5000", grpc::InsecureChannelCredentials()));
    std::string user("world");
    int reply = greeter.say_hello(user);
    std::cout << "Greeter received: " << reply << std::endl;

    return 0;
}

CMakeLists.txt

cmake_minimum_required(VERSION 3.17)

project(grpcdemo)

set(CMAKE_CXX_STANDARD 14)

find_package(Protobuf REQUIRED)

set(_PROTOBUF_LIBPROTOBUF protobuf::libprotobuf)

find_package(PkgConfig REQUIRED)
pkg_check_modules(GRPCPP REQUIRED grpc++>=1.22.0)

include_directories(
        ${GRPCPP_INCLUDE_DIRS}
        ${Protobuf_INCLUDE_DIRS}
)

link_directories(
        ${GRPCPP_LIBRARY_DIRS}
)


add_library(hellolibrary ../protos/helloworld.grpc.pb.cc ../protos/helloworld.pb.cc )

add_executable(client_bin main.cpp)

target_link_libraries(client_bin
        ${GRPCPP_LIBRARIES}
        ${_PROTOBUF_LIBPROTOBUF}
        hellolibrary
        )

#3.7 效果

• gRPC服務端

• gRPC客戶端

#4 遇到的問題

• google/protobuf/port_def.inc

'google/protobuf/port_def.inc' file not found
#include <google/protobuf/port_def.inc>
         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1 error generated.

原因: CMakeLists.txt中沒有新增protobuf的標頭檔案

解決 : include_directories(
${Protobuf_INCLUDE_DIRS}
)

• 無法找到gRPC

CMake Error at CMakeLists.txt:14 (find_package):
  By not providing "FindgRPC.cmake" in CMAKE_MODULE_PATH this project has
  asked CMake to find a package configuration file provided by "gRPC", but
  CMake did not find one.

  Could not find a package configuration file provided by "gRPC" with any of
  the following names:

    gRPCConfig.cmake
    grpc-config.cmake

  Add the installation prefix of "gRPC" to CMAKE_PREFIX_PATH or set
  "gRPC_DIR" to a directory containing one of the above files.  If "gRPC"
  provides a separate development package or SDK, be sure it has been
  installed.

原因: find_package(gRPC)

解決 : 將find_package(gRPC) 該為: find_package(PkgConfig REQUIRED)
pkg_check_modules(GRPCPP REQUIRED grpc++>=1.22.0)