asyncio-gevent

asyncio-gevent makes asyncio and gevent compatible. It provides utilities for

• running gevent on asyncio (by using asyncio as gevent's event loop, work in progress)
• running asyncio on gevent (by using gevent as asyncio's event loop)
• converting greenlets to asyncio futures
• converting futures to asyncio greenlets

asyncio-gevent is a fork and complete rewrite of aiogevent and tulipcore for modern python 3.

Install

Install asyncio-gevent from pypi using your favourite package manager.

# If you use poetry
poetry add asyncio-gevent

# If you use pip
pip install asyncio-gevent

Usage

Running gevent on asyncio

In order to run gevent on asyncio, gevent needs to be initialised to use the asyncio event loop. This is done by setting the environment variable GEVENT_LOOP to asyncio_gevent.gevent_loop.GeventLoop and then starting python.

GEVENT_LOOP=asyncio_gevent.gevent_loop.GeventLoop python3 myscript.py

gevent will now run on asyncio.

Alternatively, you can also set the loop configuration setting, preferably right after importing gevent and before monkey patching.

import gevent
gevent.config.loop = "asyncio_gevent"

Running asyncio on gevent

In order to run asyncio on gevent, we need to set the (default) EventLoopPolicy to use asyncio_gevent.EventLoopPolicy.

import gevent.monkey
gevent.monkey.patch_all()

import asyncio

import asyncio_gevent

asyncio.set_default_event_loop_policy(asyncio_gevent.EventLoopPolicy)

Converting greenlets to asyncio futures

Use asyncio_gevent.wrap_greenlet to convert a greenlet to an asyncio future. The future yields once the greenlet has finished execution.

# The following assumes that the gevent/asyncio bindings have already been initialised
import gevent

import asyncio

import asyncio_gevent


def blocking_function() -> int:
    gevent.sleep(10)
    return 42


async def main() -> None:
    greenlet = gevent.spawn(blocking_function)
    future = asyncio_gevent.wrap_greenlet()
    result = await future


asyncio.run(main())

Converting asyncio futures to greenlets

Use asyncio_gevent.yield_future to convert a future to a greenlet.

# The following assumes that the gevent/asyncio bindings have already been initialised

import gevent

import asyncio

import asyncio_gevent


async def async_function() -> int:
    await asyncio.sleep(10)
    return 42


def main() -> None:
    future = async_function()
    greenlet = asyncio_gevent.yield_future(future)
    greenlet.join()

main()

License

MIT