python-trio / purerpc

Native, async Python gRPC client and server implementation supporting asyncio, uvloop, and trio

purerpc

purerpc is a native, async Python gRPC client and server implementation supporting asyncio, uvloop, and trio (achieved with anyio compatibility layer).

This project is in maintenance mode. Updates will primarily be limited to fixing severe bugs, keeping the package usable for actively developed projects, and easing maintenance.

For use cases limited to asyncio, consider the Python package published by the main grpc project instead.

Requirements

• CPython >= 3.8
• ? PyPy >= 3.8

Installation

Latest PyPI version:

pip install purerpc[grpc]

NOTE: for PyPy, replace "grpc" with "grpc-pypy". Support is tentative, as grpc does not officially support PyPy.

Latest development version:

pip install git+https://github.com/python-trio/purerpc.git[grpc]

These invocations will include dependencies for the grpc runtime and generation of service stubs.

To install extra dependencies for running tests or examples, using the test_utils module, etc., apply the [dev] suffix (e.g. pip install purerpc[dev]).

protoc plugin

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

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

or, if you installed the 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.

Server

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


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}")


if __name__ == '__main__':
    server = Server(50055)
    server.add_service(Greeter().service)
    # NOTE: if you already have an async loop running, use "await server.serve_async()"
    import anyio
    anyio.run(server.serve_async)  # or set explicit backend="asyncio" or "trio"

Client

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

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


if __name__ == '__main__':
    # NOTE: if you already have an async loop running, use "await listen()"
    import anyio
    anyio.run(listen)  # or set explicit backend="asyncio" or "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

Project history

purerpc was originally written by Andrew Stepanov and used the curio async event loop. Later it was migrated to the anyio API, supporting asyncio, curio, uvloop, and trio (though curio support has since been dropped from the API).

After going a few years unmaintained, the project was adopted by the python-trio organization with the intent of ensuring a continued gRPC solution for Trio users.