[python] asyncio 특정 시간에 작동하도록 하기

https://stackoverflow.com/questions/51292027/how-to-schedule-a-task-in-asyncio-so-it-runs-at-a-certain-date

How to schedule a task in asyncio so it runs at a certain date?

import asyncio, datetime

async def wait_until(dt):
    # sleep until the specified datetime
    now = datetime.datetime.now()
    await asyncio.sleep((dt - now).total_seconds())

async def run_at(dt, coro):
    await wait_until(dt)
    return await coro

async def hello():
    print('hello')

loop = asyncio.get_event_loop()
# print hello ten years after this answer was written
loop.create_task(run_at(datetime.datetime(2028, 7, 11, 23, 36),
                        hello()))
loop.run_forever()

Note: Python versions before 3.8 didn't support sleeping intervals longer than 24 days, so wait_until had to work around the limitation. The original version of this answer defined it like this:

async def wait_until(dt):
    # sleep until the specified datetime
    while True:
        now = datetime.datetime.now()
        remaining = (dt - now).total_seconds()
        if remaining < 86400:
            break
        # pre-3.7.1 asyncio doesn't like long sleeps, so don't sleep
        # for more than one day at a time
        await asyncio.sleep(86400)