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Diffstat (limited to 'Doc')
| -rw-r--r-- | Doc/whatsnew/3.14.rst | 90 |
1 files changed, 90 insertions, 0 deletions
diff --git a/Doc/whatsnew/3.14.rst b/Doc/whatsnew/3.14.rst index d13cd2d..342456c 100644 --- a/Doc/whatsnew/3.14.rst +++ b/Doc/whatsnew/3.14.rst @@ -780,6 +780,96 @@ asyncio It now raises a :exc:`RuntimeError` if there is no current event loop. (Contributed by Kumar Aditya in :gh:`126353`.) + There's a few patterns that use :func:`asyncio.get_event_loop`, most + of them can be replaced with :func:`asyncio.run`. + + If you're running an async function, simply use :func:`asyncio.run`. + + Before:: + + async def main(): + ... + + + loop = asyncio.get_event_loop() + try: + loop.run_until_complete(main()) + finally: + loop.close() + + After:: + + async def main(): + ... + + asyncio.run(main()) + + If you need to start something, e.g. a server listening on a socket + and then run forever, use :func:`asyncio.run` and an + :class:`asyncio.Event`. + + Before:: + + def start_server(loop): + ... + + loop = asyncio.get_event_loop() + try: + start_server(loop) + loop.run_forever() + finally: + loop.close() + + After:: + + def start_server(loop): + ... + + async def main(): + start_server(asyncio.get_running_loop()) + await asyncio.Event().wait() + + asyncio.run(main()) + + If you need to run something in an event loop, then run some blocking + code around it, use :class:`asyncio.Runner`. + + Before:: + + async def operation_one(): + ... + + def blocking_code(): + ... + + async def operation_two(): + ... + + loop = asyncio.get_event_loop() + try: + loop.run_until_complete(operation_one()) + blocking_code() + loop.run_until_complete(operation_two()) + finally: + loop.close() + + After:: + + async def operation_one(): + ... + + def blocking_code(): + ... + + async def operation_two(): + ... + + with asyncio.Runner() as runner: + runner.run(operation_one()) + blocking_code() + runner.run(operation_two()) + + collections.abc --------------- |