purerpc

Asynchronous pure Python gRPC client and server implementation supporting asyncio, uvloop, curio and trio (achieved with anyio compatibility layer).

Requirements

• CPython >= 3.5
• PyPy >= 3.5

Installation

Latest PyPI version:

pip install purerpc

Latest development version:

pip install git+https://github.com/standy66/purerpc.git

By default purerpc uses asyncio event loop, if you want to use uvloop, curio or trio, please install them manually.

protoc plugin

purerpc adds protoc-gen-purerpc plugin for protoc to your PATH enviroment variable so you can use it to generate service definition and stubs:

protoc --purerpc_out=. --python_out=. -I. greeter.proto

or, if you installed grpcio_tools Python package:

python -m grpc_tools.protoc --purerpc_out=. --python_out=. -I. greeter.proto

Usage

NOTE: greeter_grpc module is generated by purerpc's protoc-gen-purerpc plugin.

Below are the examples for Python 3.6 and above which introduced asynchronous generators as a language concept. For Python 3.5, where native asynchronous generators are not supported, you can use async_generator library for this purpose. Just mark yielding coroutines with @async_generator decorator and use await yield_(value) and await yield_from_(async_iterable) instead of yield.

Server

from greeter_pb2 import HelloRequest, HelloReply
from greeter_grpc import GreeterServicer
from purerpc import Server


class Greeter(GreeterServicer):
    async def SayHello(self, message):
        return HelloReply(message="Hello, " + message.name)

    async def SayHelloToMany(self, input_messages):
        async for message in input_messages:
            yield HelloReply(message=f"Hello, {message.name}")


server = Server(50055)
server.add_service(Greeter().service)
server.serve(backend="asyncio")  # backend can also be one of: "uvloop", "curio", "trio"

Client

import anyio
import purerpc
from greeter_pb2 import HelloRequest, HelloReply
from greeter_grpc import GreeterStub


async def gen():
    for i in range(5):
        yield HelloRequest(name=str(i))


async def main():
    async with purerpc.insecure_channel("localhost", 50055) as channel:
        stub = GreeterStub(channel)
        reply = await stub.SayHello(HelloRequest(name="World"))
        print(reply.message)

        async for reply in stub.SayHelloToMany(gen()):
            print(reply.message)


if __name__ == "__main__":
    anyio.run(main, backend="asyncio")  # backend can also be one of: "uvloop", "curio", "trio"

You can mix server and client code, for example make a server that requests something using purerpc from another gRPC server, etc.

More examples in misc/ folder