Python 3 Object-Oriented Programming - Third Edition

AsyncIO in action

A canonical example of a blocking function is the time.sleep call. Let's use the asynchronous version of this call to illustrate the basics of an AsyncIO event loop, as follows:

import asyncioimport randomasync def random_sleep(counter):    delay = random.random() * 5    print("{} sleeps for {:.2f} seconds".format(counter, delay))    await asyncio.sleep(delay)    print("{} awakens".format(counter))async def five_sleepers():    print("Creating five tasks")    tasks = [asyncio.create_task(random_sleep(i)) for i in range(5)]    print("Sleeping after starting five tasks")    await asyncio.sleep(2)    print("Waking and waiting for five tasks")    await asyncio.gather(*tasks)asyncio.get_event_loop().run_until_complete(five_sleepers())print("Done five tasks") ...