Coroutine as background job in Jupyter notebook

Question

I have a coroutine which I'd like to run as a "background job" in a Jupyter notebook. I've seen ways to accomplish this using threading, but I'm wondering whether it's also possible to hook into the notebook's event loop.

For example, say I have the following class:

import asyncio
class Counter:
    def __init__(self):
        self.counter = 0

    async def run(self):
        while True:
            self.counter += 1
            await asyncio.sleep(1.0)

t = Counter()

and I'd like to execute the run method (which loops indefinitely), while still being able to check the t.counter variable at any point. Any ideas?

Answer 1

The following basically does what I want I think, but it does use a separate thread. However, I can still use the async primitives.

def run_loop():
    loop = asyncio.new_event_loop()
    run_loop.loop = loop
    asyncio.set_event_loop(loop)
    task = loop.create_task(t.run())
    loop.run_until_complete(task)

from IPython.lib import backgroundjobs as bg
jobs = bg.BackgroundJobManager()
jobs.new('run_loop()')
loop = run_loop.loop # to access the loop outside

Answer 2

I think your code works perfectly, you just need to create a task to wrap the coroutine, i.e. :

import asyncio
class Counter:
    def __init__(self):
        self.counter = 0

    async def run(self):
        while True:
            self.counter += 1
            await asyncio.sleep(1.0)

t = Counter()
asyncio.create_task(t.run())

wait 10 seconds, and check

t.counter

should get

> 10

Answer 3

There's a simplified version of what Mark proposed:

from IPython.lib import backgroundjobs as bg
jobs = bg.BackgroundJobManager()
jobs.new(asyncio.get_event_loop().run_forever)

If you need, you can access the loop with asyncio.get_event_loop()