async_event.py

import asyncio

"""
hello
hello
hello
bye
"""

interval_event = asyncio.Event()
exit_event = asyncio.Event()


async def wait_event():
    await interval_event.wait()
    interval_event.clear()


async def listen_event():
    while True:
        await wait_event()
        print("hello")


async def interval():
    for _ in range(3):
        await asyncio.sleep(1)
        interval_event.set()

    await exit_event.wait()


async def not_exit():
    await asyncio.gather(listen_event(), interval())


async def wait_exit():
    await asyncio.sleep(20)
    print("bye")


async def main():
    _, pending = await asyncio.wait(
        map(asyncio.create_task, (not_exit(), wait_exit())),
        return_when=asyncio.FIRST_COMPLETED,
    )

    for task in pending:
        task.cancel()


loop = asyncio.get_event_loop()
loop.run_until_complete(main())

async_generator.py

import asyncio

"""
hello
hello
hello
"""


async def interval_event():
    for _ in range(3):
        yield "hello"
        await asyncio.sleep(1)


async def listen_event():
    async for _ in interval_event():
        print("hello")


async def not_exit():
    await asyncio.gather(listen_event())


async def wait_exit():
    await asyncio.sleep(20)
    print("bye")


async def main():
    _, pending = await asyncio.wait(
        map(asyncio.create_task, (not_exit(), wait_exit())),
        return_when=asyncio.FIRST_COMPLETED,
    )

    for task in pending:
        task.cancel()


loop = asyncio.get_event_loop()
loop.run_until_complete(main())

hello
hello
hello
bye