aiorun 2017.10.3

Boilerplate for asyncio applications

ALPHA

aiorun

Here’s the big idea (how you use it):

import asyncio
from aiorun import run

async def main():
    # Put your application code here
    await asyncio.sleep(1.0)

if __name__ == '__main__':
    run(main())

This package provides a run() function as the starting point of your asyncio-based application.

So what the heck does run() do exactly?? It:

• creates a Task for the given coroutine (schedules it on the event loop),

• calls loop.run_forever(),

• adds default (and smart) signal handlers for both SIGINT and SIGTERM that will stop the loop, and then it…

• gathers all outstanding tasks,

• cancels them using task.cancel() (you can choose whether or not to handle CancelledError in your coroutines),

• waits for the executor to complete shutdown, and

• finally closes the loop.

All of this stuff is boilerplate that you will never have to write again. So, if you use aiorun this is what you need to remember:

• Spawn all your work from a single, starting coroutine

• When a shutdown signal is received, all currently-pending tasks will have CancelledError raised internally. It’s up to you whether you want to handle this in a try/except or not.

• Try to have executor jobs be shortish, since shutdown will wait for them to finish. If you need a long-running thread or process tasks, use a dedicated thread/subprocess and set daemon=True instead.

There’s not much else to know.