Flask 部署在 heroku 上的 App Apscheduler 无法在后台运行

Question

In my flask app I want to schedule a function to run in a regular time interval which I have deployed on heroku . Which works perfectly when the interval is in few minutes or seconds but not for hours. I am using Aps Scheduler.

Here is my python file which contains the scheduler.

#price_drop.py

from apscheduler.schedulers.background import BackgroundScheduler
schedule = BackgroundScheduler()

def CheckPrice():
    print("Running")

schedule.add_job(id= "Tracker",func = CheckPrice,trigger='interval',hours = 1)
schedule.start()

There are other features which should run in parallel(routes).

run.py

from app import app

if __name__ == '__main__':
   app.run(debug=True)

Here are some heroku configurations

Procfile

web: gunicorn app:app
clock: python price_drop.py

Also Added below command in powershell

heroku ps:scale clock=1

I think the scheduler is running in background so I need to keeping the file alive. Can plz anyone suggest me an efficient way to do this. Or am I going wrong anywhere in the code.

Answer 1

If you are trying to run actual computation within the clock process. It is not the way to handle scheduled executions in heroku.

You'll need

• A single clock process (like the one you already have). Which will queue tasks in a message queue like redis
• A worker process that listens to redis queue and processes tasks
• A message queue like redis

Here some guides about achieving what you want

• Scheduled Jobs with Custom Clock Processes in Python with APScheduler
• Background Tasks in Python with RQ

If you are not planning on scaling up the web worker beyond 1, you can directly add APScheduler within the Flask app.