Fix asyncio.run() in Jupyter notebook

Description

By design, asyncio does not allow its event loop to be nested. This presents a practical problem in Jupyter notebooks because the notebook itself runs inside an event loop. Consequently, you cannot use asyncio.run() to execute tasks and wait for the result in the standard way.

Example

import asyncio
 
async def test_async():  
    print("Starting async function")  
    await asyncio.sleep(1)  
    print("Async function completed")
 
asyncio.run(test_async())

ran in a notebook cell will raise:

RuntimeError: asyncio.run() cannot be called from a running event loop

Solutions

You have two options to resolve this issue:

1. In modern JupyterLab or Jupyter Notebook environments (specifically, those using IPython version 7.0 or newer), you can directly await a coroutine in a cell:

   await test_async()

   >>> Starting async function
   >>> Async function completed
   

2. Use nest_asyncio to allow the event loop to be nested. This approach keeps your code closer to how it would look in a standard Python (.py) file: First install nest_asyncio with the package manager of your choice:

   pip install nest_asyncio

   Then, apply the patch at the beginning of the notebook:

   import asyncio
   import nest_asyncio
    
   nest_asyncio.apply()
    
   async def test_async():  
       print("Starting async function")  
       await asyncio.sleep(1)  
       print("Async function completed")
    
   asyncio.run(test_async())

   >>> Starting async function
   >>> Async function completed