fastapi_cron.py

# Cron Pattern
import asyncio
from fastapi import FastAPI

server = FastAPI()

server.cron_jobs = asyncio.Queue()

def cron(interval: int):
    def cron_setup(f):
        async def cron_job():
            await f()
            await asyncio.sleep(interval)
            await server.cron_jobs.put(cron_job)
        asyncio.create_task(server.cron_jobs.put(cron_job))
        return f
    return cron_setup

async def cron_worker():
    print(f"starting cron_worker")
    while True:
        try:
            job = await server.cron_jobs.get()
            result = await job()
        except Exception as e:
            if not isinstance(e, asyncio.CancelledError):
                log.exception(f"error with cron worker")
                continue
            break

@cron(60)
async def important_recurring_task():
    print(f"starting important_recurring_task")
    await asyncio.sleep(10)
    print(f"finished important_recurring_task")

@server.on_event('startup')
async def startup_tasks():
    asyncio.create_task(cron_worker())