/aioshutdown

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

Primary LanguagePythonMIT LicenseMIT

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