aiojobs: Jobs scheduler for managing background task¶
The library gives controlled way for scheduling background tasks for
asyncio applications.
Installation¶
$ pip3 install aiojobs
Usage example¶
import asyncio
import aiojobs
async def coro(timeout):
await asyncio.sleep(timeout)
async def main():
async with aiojobs.Scheduler() as scheduler:
for i in range(100):
# spawn jobs
await scheduler.spawn(coro(i/10))
await asyncio.sleep(5.0)
# not all scheduled jobs are finished at the moment
# Exit from context will gracefully wait on tasks before closing
# any remaining spawned jobs
asyncio.run(main())
For further information read Quickstart, Introduction and API.
Shielding tasks with a scheduler¶
It is typically recommended to use asyncio.shield() to protect tasks
from cancellation. However, the inner shielded tasks can’t be tracked and
are therefore at risk of being cancelled during application shutdown.
To resolve this issue aiojobs includes a aiojobs.Scheduler.shield()
method to shield tasks while also keeping track of them in the scheduler.
In combination with the aiojobs.Scheduler.wait_and_close() method,
this allows shielded tasks the required time to complete successfully
during application shutdown.
For example:
import asyncio
import aiojobs
from contextlib import suppress
async def important():
print("START")
await asyncio.sleep(5)
print("DONE")
async def run_something(scheduler):
# If we use asyncio.shield() here, then the task doesn't complete and DONE is never printed.
await scheduler.shield(important())
async def main():
async with aiojobs.Scheduler() as scheduler:
t = asyncio.create_task(run_something(scheduler))
await asyncio.sleep(0.1)
t.cancel()
with suppress(asyncio.CancelledError):
await t
asyncio.run(main())
Integration with aiohttp.web¶
from aiohttp import web
from aiojobs.aiohttp import setup, spawn
import aiojobs
async def handler(request):
await spawn(request, coro())
return web.Response()
app = web.Application()
app.router.add_get('/', handler)
setup(app)
or just
from aiojobs.aiohttp import atomic
@atomic
async def handler(request):
return web.Response()
Source code¶
The project is hosted on GitHub: https://github.com/aio-libs/aiojobs
Please feel free to file an issue on the bug tracker if you have found a bug or have some suggestion in order to improve the library.
Communication channels¶
Gitter Chat https://gitter.im/aio-libs/Lobby
We support Stack Overflow. Please add python-asyncio or aiohttp tag to your question there.
