aioshutdown

Context manager that provides simple graceful shutdown interface for your asyncio tasks.

Installation

pip install -U aioshutdown

Usage

Just specify the list of signals that you want to intercept using the | operator:

from aioshutdown import SIGTERM, SIGINT, SIGHUP


with SIGTERM | SIGHUP | SIGINT as loop:
    ...

The context manager will return an instance of the current event loop. You can intercept signals directly inside your coroutines:

async def my_task(sleep: int):
    try:
        """ Main logic of your coroutine. """
    except asyncio.CancelledError as exc:
        """ In this place you can gracefully complete the work. """

Full example:

import asyncio
from aioshutdown import SIGTERM, SIGINT, SIGHUP
import logging


logging.basicConfig(
    level=logging.INFO,
    format="%(asctime)s,%(msecs)d %(levelname)s: %(message)s",
    datefmt="%H:%M:%S",
)

async def my_task(sleep: int):
    try:
        while True:
            logging.info("Sleep from task #%s", sleep)
            await asyncio.sleep(sleep)
    except asyncio.CancelledError as exc:
        # Received an exit signal. In this place we gracefully complete the work.
        signal = exc.args[0] # NOTE: works in Python >= 3.9 only: https://docs.python.org/3/library/asyncio-future.html?highlight=Changed%20in%20version%203.9:%20Added%20the%20msg%20parameter.#asyncio.Future.cancel
        logging.warning("Received %s signal. Shutting down...", signal.value)

# Usage with `run_forever`

with SIGTERM | SIGHUP | SIGINT as loop:
    tasks = [loop.create_task(my_task(i)) for i in range(1, 10)]
    loop.run_forever()

# Usage with `run_until_complete`

with SIGTERM | SIGHUP | SIGINT as loop:
    tasks = [loop.create_task(my_task(i)) for i in range(1, 10)]
    loop.run_until_complete(asyncio.gather(*results))

Output

23:04:05,798 INFO: Sleep from task #1
23:04:05,798 INFO: Sleep from task #2
23:04:06,799 INFO: Sleep from task #1
23:04:07,800 INFO: Sleep from task #2
23:04:07,800 INFO: Sleep from task #1
23:04:08,801 INFO: Sleep from task #1
^C23:04:09,504 INFO: Received exit signal SIGINT...
23:04:09,504 INFO: Cancelling 2 outstanding tasks
23:04:09,504 WARNING: Received 2 signal. Shutting down...
23:04:09,504 WARNING: Received 2 signal. Shutting down...
23:04:09,504 INFO: Stopping event loop

Useful links

Graceful Shutdowns with asyncio