Simple gRPC server based on Python

To develop a gRPC server in Python, you first define your service using a Protocol Buffer (.proto) file, then generate Python code from this file using the protoc compiler with the gRPC Python plugin. This generated code provides the necessary structures. Next, you create a class that inherits from the generated service class and implements the methods defined in your .proto file. Finally, you create a gRPC server instance, register your service implementation, and start listening on a specified port, handling incoming client requests.
 

Here’s a step-by-step guide to set up and use gRPC in Python, along with example code:

Step 1: Install the Required Libraries

Install grpcio and grpcio-tools for gRPC support in Python.

pip install grpcio grpcio-tools

Step 2: Define the gRPC Service Using Protocol Buffers

Create a file named example.proto with the following content:

syntax = "proto3";

service ExampleService {
  rpc SayHello (HelloRequest) returns (HelloResponse);
}

message HelloRequest {
  string name = 1;
}

message HelloResponse {
  string message = 1;
}

Step 3: Generate Python Code from the Proto File

Generate the Python gRPC classes from the .proto file:

python -m grpc_tools.protoc -I. --python_out=. --grpc_python_out=. example.proto

This creates two files:

• example_pb2.py (message definitions)
• example_pb2_grpc.py (gRPC service definitions)

Step 4: Implement the gRPC Service

Create a server implementation:

server.py

from concurrent import futures
import grpc
import example_pb2
import example_pb2_grpc

class ExampleServiceServicer(example_pb2_grpc.ExampleServiceServicer):
    def SayHello(self, request, context):
        name = request.name
        return example_pb2.HelloResponse(message=f"Hello, {name}!")

def serve():
    server = grpc.server(futures.ThreadPoolExecutor(max_workers=10))
    example_pb2_grpc.add_ExampleServiceServicer_to_server(ExampleServiceServicer(), server)
    server.add_insecure_port("[::]:50051")
    print("Server is running on port 50051")
    server.start()
    server.wait_for_termination()

if __name__ == "__main__":
    serve()

Step 5: Create the gRPC Client

client.py

import grpc
import example_pb2
import example_pb2_grpc

def run():
    with grpc.insecure_channel("localhost:50051") as channel:
        stub = example_pb2_grpc.ExampleServiceStub(channel)
        response = stub.SayHello(example_pb2.HelloRequest(name="World"))
    print(f"Received: {response.message}")

if __name__ == "__main__":
    run()

Step 6: Run the Server and Client

1. Start the server by running:

   python server.py
   

2. Run the client in a separate terminal:

   python client.py
   

Output

When you run the client, it will send a request to the server, and the server will respond:

Server:
Server is running on port 50051

Client:
Received: Hello, World!

This is a simple gRPC service setup in Python. You can expand it by adding more methods, using TLS for secure communication, or deploying it in a production environment.