asyncio - how to stop background task cleanly

Frank Millman frank at chagford.com
Sun Feb 7 00:27:19 EST 2016


"Marko Rauhamaa"  wrote in message news:8737t5shhp.fsf at elektro.pacujo.net...
> >
> Actually, cancellation is specially supported in asyncio (<URL:
> https://docs.python.org/3/library/asyncio-task.html#asyncio.Task.cancel>)
> so this should do:
>
>     async def background_task():
>         while True:
>             await perform_task()
>             await asyncio.sleep(10)
>

That's exactly what I needed - thanks, Marko

    async def background_task()
        try:
            while True:
                await perform_task()
                await asyncio.sleep(10)
        except asyncio.CancelledError:
                await perform_cleanup()

At startup -

    task = asyncio.ensure_future(background_task())

At shutdown -

    task.cancel()
    await asyncio.wait([task])

Works perfectly - thanks again.

Frank




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