""" Example demonstrating use with ASGI (raw ASGI application, no framework). Requires the "postgresql" service to be running. To install prerequisites: pip install sqlalchemy asyncpg uvicorn To run: uvicorn asgi_noframework:app It should print a line on the console on a one-second interval while running a basic web app at http://localhost:8000. """ from __future__ import annotations from datetime import datetime from sqlalchemy.ext.asyncio import create_async_engine from apscheduler.datastores.sqlalchemy import SQLAlchemyDataStore from apscheduler.eventbrokers.asyncpg import AsyncpgEventBroker from apscheduler.schedulers.async_ import AsyncScheduler from apscheduler.triggers.interval import IntervalTrigger def tick(): print("Hello, the time is", datetime.now()) async def original_app(scope, receive, send): """Trivial example of an ASGI application.""" if scope["type"] == "http": await receive() await send( { "type": "http.response.start", "status": 200, "headers": [ [b"content-type", b"text/plain"], ], } ) await send( { "type": "http.response.body", "body": b"Hello, world!", "more_body": False, } ) elif scope["type"] == "lifespan": while True: message = await receive() if message["type"] == "lifespan.startup": await send({"type": "lifespan.startup.complete"}) elif message["type"] == "lifespan.shutdown": await send({"type": "lifespan.shutdown.complete"}) return async def scheduler_middleware(scope, receive, send): if scope["type"] == "lifespan": engine = create_async_engine( "postgresql+asyncpg://postgres:secret@localhost/testdb" ) data_store = SQLAlchemyDataStore(engine) event_broker = AsyncpgEventBroker.from_async_sqla_engine(engine) async with AsyncScheduler(data_store, event_broker) as scheduler: await scheduler.add_schedule(tick, IntervalTrigger(seconds=1), id="tick") await scheduler.start_in_background() await original_app(scope, receive, send) else: await original_app(scope, receive, send) # This is just for consistency with the other ASGI examples app = scheduler_middleware