Lifespan

Kuí allows registering multiple event handlers to run code before the application starts or before it shuts down.

• on_startup: Function to run before Kuí starts
• on_shutdown: Function to run before Kuí shuts down

Registering Events

You can register event handlers using decorator syntax. Both regular functions and async functions defined with async def can be registered.

import logging

from kui.asgi import Kui

app = Kui()
logger = logging.getLogger("example")


@app.on_startup
def logger_on_startup(app: Kui):
    logger.info("Called on startup")


@app.on_shutdown
def logger_on_shutdown(app: Kui):
    logger.info("Called on shutdown")

You can also pass them as arguments when creating the Kui object. The following code is equivalent to the previous example.

import logging

from kui.asgi import Kui

logger = logging.getLogger("example")


def logger_on_startup(app: Kui):
    logger.info("Called on startup")


def logger_on_shutdown(app: Kui):
    logger.info("Called on shutdown")


app = Kui(
    on_startup=[logger_on_startup],
    on_shutdown=[logger_on_shutdown],
)

asynccontextmanager

Kuí provides the asynccontextmanager_lifespan function, which can convert an async generator function into on_startup and on_shutdown event handlers.

from kui.asgi.lifespan import asynccontextmanager_lifespan


async def f(app: Kui):
    logger.info("Called on startup")
    yield
    logger.info("Called on shutdown")


on_startup, on_shutdown = asynccontextmanager_lifespan(f)
app = Kui(
    on_startup=[on_startup],
    on_shutdown=[on_shutdown],
)