asyncio-exception-example.py

import asyncio


@asyncio.coroutine
def shleepy_time(seconds):
    print("Shleeping for {s} seconds...".format(s=seconds))
    yield from asyncio.sleep(seconds)
    print("Done shleeping.")


@asyncio.coroutine
def raise_hell():
    raise Exception('hell')


if __name__ == '__main__':
    loop = asyncio.get_event_loop()

    # Side note: Apparently, async() will be deprecated in 3.4.4.
    # See: https://docs.python.org/3.4/library/asyncio-task.html#asyncio.async
    tasks = asyncio.gather(
        asyncio.async(shleepy_time(seconds=2)),
        asyncio.async(shleepy_time(seconds=5)),
        asyncio.async(raise_hell())
    )
        # return_exceptions=True)

    try:
        loop.run_until_complete(tasks)
    except Exception as e:
        print("Caught:", e)
        tasks.cancel()
        loop.run_forever()
        tasks.exception()
    finally:
        loop.close()

This gist was posted to support a question I asked on Stack Overflow. You can see an explanation of why this code hangs in an infinite loop here.