Running asyncio

Warning

Using asyncio in a notebook is NOT trivial

But it can be done.

If done wrong the error message:

This event loop is already running appears.

For any asyncio functionality to run on Jupyter Notebook you cannot invoke a run_until_complete(), since the loop you will receive from asyncio.get_event_loop() will be active.

So for correct working you must add the task to the current loop:

import asyncio
loop = asyncio.get_event_loop()
loop.create_task(some_async_function())

See: https://blog.jupyter.org/ipython-7-0-async-repl-a35ce050f7f7

Note

Use result() Return the result of the Task. function of asyncio, see https://docs.python.org/3/library/asyncio-task.html#asyncio.run

Using JupyterLab in combination with Python programs that use asyncio

Running or importing Python libraries that use asyncio or zmq sockets is unlikely to work.

But you can use Python programs that use asyncio.

Just do run your Python program which uses asyncio as script:

%%sx
./[your python program].py [argument(s)]

Tip

Capture the output in the notebook. In this way the Python program which has process running in parallel under asyncio do work. The Python program is simply executed by the shell. This prevents interference with core JupyterLab processes.