import asyncio

from grpclib.client import Channel

# generated by protoc
from .helloworld_pb2 import HelloRequest, HelloReply
from .helloworld_grpc import GreeterStub


async def main():
    channel = Channel('127.0.0.1', 50051)
    greeter = GreeterStub(channel)

    reply: HelloReply = await greeter.SayHello(HelloRequest(name='Dr. Strange'))
    print(reply.message)

    channel.close()


if __name__ == '__main__':
    asyncio.run(main())

import asyncio

from grpclib.utils import graceful_exit
from grpclib.server import Server

# generated by protoc
from .helloworld_pb2 import HelloRequest, HelloReply
from .helloworld_grpc import GreeterBase


class Greeter(GreeterBase):

    async def SayHello(self, stream):
        request: HelloRequest = await stream.recv_message()
        message = f'Hello, {request.name}!'
        await stream.send_message(HelloReply(message=message))


async def main(*, host='127.0.0.1', port=50051):
    server = Server([Greeter()])
    with graceful_exit([server]):
        await server.start(host, port)
        print(f'Serving on {host}:{port}')
        await server.wait_closed()


if __name__ == '__main__':
    asyncio.run(main())

$ pip3 install grpclib protobuf

$ pip3 install --upgrade --pre grpclib

$ brew install protobuf  # example for macOS users
$ protoc --version
libprotoc ...

$ pip3 install grpcio-tools
$ python3 -m grpc_tools.protoc --version
libprotoc ...

$ python3 -m grpc_tools.protoc -I. --python_out=. --python_grpc_out=. helloworld/helloworld.proto