GRPC

GRPC

remote procedure call 远程过程调用，使用的时候客户端调用server端提供的接口就像是调用本地的函数一样。

Protobuf

Protobuf实际是一套类似Json或者XML的数据传输格式和规范，用于不同应用或进程之间进行通信时使用。通信时所传递的信息是通过Protobuf定义的message数据结构进行打包，然后编译成二进制的码流再进行传输或者存储

步骤：
1.通过protobuf来定义接口和数据类型

syntax = "proto3";
// The greeting service definition.
service Greeter {
  // Sends a greeting
  rpc SayHello (HelloRequest) returns (HelloReply) {}
  // Sends another greeting
  rpc SayHelloAgain (HelloRequest) returns (HelloReply) {}
}

message HelloRequest {
  string name = 1;
}

message HelloReply {
  string message = 1;
}

2.使用gRPC protobuf生成工具生成对应语言的库函数
python -m grpc_tools.protoc -I./ --python_out=. --grpc_python_out=. helloworld.proto
I: 是设定源路径
--python_out: 用于设定编译后的输出结果，其它语言请使用对应语言的option,最后一个参数是你要编译的proto文件

GRPC server端代码

from concurrent import futures
import time
import grpc
import hello_world_pb2 as helloworld_pb2
import hello_world_pb2_grpc as helloworld_pb2_grpc

_ONE_DAY_IN_SECONDS = 60 * 60 * 24


class Greeter(helloworld_pb2_grpc.GreeterServicer):
    # 工作函数(方法重写)
    def SayHello(self, request, context):
        print(request.name)
        message = "This message is from Server.And what i want to say is hello " " + request.name + " "";
        return helloworld_pb2.HelloReply(message = message)


def serve():
    # gRPC 服务器
    server = grpc.server(futures.ThreadPoolExecutor(max_workers=4))
    helloworld_pb2_grpc.add_GreeterServicer_to_server(helloworld_pb2_grpc.GreeterServicer(), server)
    server.add_insecure_port('[::]:50051')
    print("sever is opening ,waiting for message...")
    server.start()  # start() 不会阻塞，如果运行时你的代码没有其它的事情可做，需要循环等待。
    try:
        while True:
            print('666')
            time.sleep(_ONE_DAY_IN_SECONDS)
    except KeyboardInterrupt:
        server.stop(0)

if __name__ == '__main__':
    serve()

GRPC client端代码

import hello_world_pb2_grpc, hello_world_pb2
import grpc

def run():
    channel = grpc.insecure_channel('localhost:50051')
    stub = hello_world_pb2_grpc.GreeterStub(channel)
    response = stub.SayHello(hello_world_pb2.HelloRequest(name='donghao'))
    print("Greeter client received: " + response.message)
    response = stub.SayHelloAgain(hello_world_pb2.HelloRequest(name='donghao123'))
    print("Greeter client received: " + response.message)

if __name__ == '__main__':
    run()

output:
Greeter client received: Hello, donghao!

Greeter client received: Hello again, donghao123!