Graceful shutdown of signal handlers

When signals are added, we should run some sort of a cleanup like this on shutdown to make sure any custom signals are run. This also includes a suggestion that we identify them with a name: signal-XXXXX.

async def cleanup(app, _):
    for task in asyncio.all_tasks():
        if task.get_name().startswith("signal"):
          await task

[jonathanstaniforth]

Hi @ahopkins 👋 , I’m interested in taking this as my first issue! I have some ideas and questions which I will discuss below.

If I followed the flow correctly, I believe the task for signal handlers gets created in the sanic.signals.SignalRouter.dispatch method. In which case, a name could be assigned to the task like so:

task = asyncio.get_running_loop().create_task(dispatch, name="signal")

For the XXXXX part of the signal task’s name, what were you thinking of passing here?

For the running of signal tasks on shutdown, I was thinking that a new method could be added to sanic.app.Sanic that’s similar to the sanic.app.Sanic.shutdown_tasks method. This method would then be called in the sanic.mixins.runner.RunnerMixin.stop method to run the signal tasks on shutdown. Is this approach similar to what you were looking for?

[ahopkins]

asyncio tasks, not background tasks

How are you distinguishing these?

Do we also need to clean unnamed background tasks in the clean shutdown?

I am hesitant to do this because it may or may not be desirable. If anything it should be controllable by config.