通过go和python进行gprc演示

Question

I want to get a Grpc demo which client is Golang and server is Python. I use Grpc official code as my demo, but it's doesn't work. Can someone help me?

If I generate the client and server by same language, example: Python or Golang. It works correctly.

1. helloworld.proto

syntax = "proto3";

package helloworld;

// The greeting service definition.
service Greeter {
  // Sends a greeting
  rpc SayHello (HelloRequest) returns (HelloReply) {}
}

// The request message containing the user's name.
message HelloRequest {
  string name = 1;
}

// The response message containing the greetings
message HelloReply {
  string message = 1;
}

2.get relevant code

1) get python relevant code: python -m grpc_tools.protoc --python_out=. --grpc_python_out=. -I. helloworld.proto

2) get go relevant code: protoc -I . helloworld.proto --go_out=plugins=grpc:.

1. helloworld_grpc_server.py

import time
import logging
import grpc
from concurrent import futures

import helloworld_pb2
import helloworld_pb2_grpc

_ONE_DAY_IN_SECONDS = 60 * 60 * 24


class Greeter(helloworld_pb2_grpc.GreeterServicer):

    def SayHello(self, request, context):
        return helloworld_pb2.HelloReply(message='Hello, %s!' % request.name)


def serve():
    server = grpc.server(futures.ThreadPoolExecutor(max_workers=10))
    helloworld_pb2_grpc.add_GreeterServicer_to_server(Greeter(), server)
    server.add_insecure_port('[::]:50051')
    server.start()
    try:
        while True:
            time.sleep(_ONE_DAY_IN_SECONDS)
    except KeyboardInterrupt:
        server.stop(0)


if __name__ == '__main__':
    logging.basicConfig()
    serve()

1. greeter_client/main.go

package main

import (
    "context"
    "log"
    "os"
    "time"

    "google.golang.org/grpc"

    pb "demo/grpc/go_python/helloworld"
)

const (
    address     = "localhost:50051"
    defaultName = "world"
)

func main() {
    // Set up a connection to the server.
    conn, err := grpc.Dial(address, grpc.WithInsecure())
    if err != nil {
        log.Fatalf("did not connect: %v", err)
    }
    defer conn.Close()
    c := pb.NewGreeterClient(conn)

    // Contact the server and print out its response.
    name := defaultName
    if len(os.Args) > 1 {
        name = os.Args[1]
    }
    ctx, cancel := context.WithTimeout(context.Background(), time.Second)
    defer cancel()
    r, err := c.SayHello(ctx, &pb.HelloRequest{Name: name})
    if err != nil {
        log.Fatalf("could not greet: %v", err)
    }
    log.Printf("Greeting: %s", r.Message)
}

1. run the demo

server:
python helloworld_grpc_server.py

client:
go run main.go

But, I get the wrong output for client:

2019/08/07 19:18:03 could not greet: rpc error: code = Unimplemented desc = Method not found!
exit status 1

I expect to the demo work.