Lifespan¶

future.lifespan.Lifespan is the ASGI lifespan hook required by Future. You pass in lists of Tasks to run at startup, on a schedule while the app is up, and at shutdown.

from future.lifespan import Lifespan
from future.tasks import Task, Unit
from future.application import Future

lifespan = Lifespan(
    startup_tasks=[
        Task("boot", func=on_boot),
    ],
    shutdown_tasks=[
        Task("teardown", func=on_shutdown),
    ],
    cron_tasks=[
        Task("scrape", interval=1, unit=Unit.HOURS, func=scraper),
    ],
)
app = Future(lifespan=lifespan, config=config)

Slots¶

List	When
startup_tasks	Once on ASGI startup, in order
cron_tasks	Registered with the interval scheduler after startup
shutdown_tasks	Once on ASGI shutdown, after the scheduler stops

Empty lists are fine:

Lifespan(startup_tasks=[], shutdown_tasks=[], cron_tasks=[])

Lifecycle¶

1. Run startup_tasks (async awaited, sync in a thread pool).
2. Start CronScheduler and register cron_tasks.
3. App serves traffic; interval tasks fire in the background.
4. On shutdown: stop the scheduler, then run shutdown_tasks.

How to build a Task (name, func, interval, jitter, …): see Tasks.