gRPC Python HelloWorld

Overview

gRPC is a high-performance RPC framework using HTTP/2 that allows services to communicate efficiently over the network. This example shows how to implement a basic client-server HelloWorld service in Python.

What's Happening

Server: Creates a gRPC server that listens on port 50051. The Greeter class implements the SayHello RPC method, which takes a name as input and returns a formatted greeting message.

Client: Establishes an insecure channel to the server at localhost:50051, creates a stub to call the remote service, and invokes the SayHello method with a name parameter to receive the response.

Prerequisites

Python 3.6 or higher
pip (Python package manager)
gRPC library and protobuf compiler

Requirements to Run

Install dependencies: pip install -r requirements.txt (which includes grpcio and grpcio-tools)
Generate Python stub files from the .proto file using python -m grpc_tools.protoc
Run the server: python server.py
In another terminal, run the client: python client.py

Implementation

from concurrent import futures
import logging

import grpc
import helloworld_pb2
import helloworld_pb2_grpc


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()
    server.wait_for_termination()


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

from __future__ import print_function

import logging

import grpc
import helloworld_pb2
import helloworld_pb2_grpc


def run():
    # NOTE(gRPC Python Team): .close() is possible on a channel and should be
    # used in circumstances in which the with statement does not fit the needs
    # of the code.
    with grpc.insecure_channel('localhost:50051') as channel:
        stub = helloworld_pb2_grpc.GreeterStub(channel)
        response = stub.SayHello(helloworld_pb2.HelloRequest(name='you'))
    print("Greeter client received: " + response.message)


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