Example of Python code to run a slow call to several resources asynchronously and execute some callback function on return

async_run_example.py

import asyncio

def worker_that_waits_for_network_io(data, ...):
   ...
   return result

def callback_hook(retrieved_data, ...):
    ...
    
    
async def async_worker(data, ...)
    loop = asyncio.get_event_loop()
    retrieved_data = await loop.run_in_executor(None, worker_that_waits_for_network_io, data, ...)
    return callback_hook(retrieved_data)

all_data = [
    ("url1.com", ...),
    ("url2.com", ...),
    ("database3", ...),
    ("url4.com", ...),
]    

loop = asyncio.get_event_loop()
results = asyncio.run(asyncio.gather(*(async_worker(*data_line) for data_line in all_data)))