exploring exception handling and resuming with asyncio.

snippets.py

import random, asyncio, time, os


async def a(n):
    global last_task
    last_task = asyncio.current_task()
    while True:
        print(n)
       
        await asyncio.sleep(0.5 + random.random() / 3)


async def main(tasks, n):
    loop = asyncio.get_running_loop()
    loop.set_exception_handler(xis)
    tasks.update({asyncio.create_task(a(i)) for i in range(n)})
    done = "nenhuma"
    old_tasks = tasks.copy()
    tasks.clear()
    tasks.update(t for t in old_tasks if not t.cancelled())
    try:
        
        await asyncio.gather(*tasks)
    except asyncio.CancelledError:
        print("xi. tentaram cancelar uma aqui")
manager(4)


def manager(n):
    tasks = set()
    loop = asyncio.new_event_loop()
    while True:
        try:        
            loop.run_until_complete(main(tasks, n))
        except KeyboardInterrupt:
            print(f"fora do loop. Tasks: {tasks}")
            last_task.cancel()
            print(tasks)
            old_tasks = tasks.copy()
            tasks.clear()
            tasks.update(t for t in old_tasks if not t.cancelled())
            if not tasks:
                # cabo as task 
                break
            print(f"{len(tasks)} restantes!")
            time.sleep(1)
            n = 0
manager(5)

the_civilized_way.py

import signal, asyncio


async def a():
    print("starting")
    await asyncio.sleep(3)
    print("finishing")


def handler(loop):
    print(f"ctrl + c detected in task in {loop}")


def main():
    loop = asyncio.new_event_loop()
    loop.add_signal_handler(signal.SIGINT, handler, loop)
    loop.run_until_complete(a())
    loop.close()


main()