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Alin Climente
Alin Climente

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How to create a simple scheduler in Django

If you need to run a function every X minutes/seconds etc. to do some cleanups, trigger some operations you can do a simple scheduler with the help of threading module and django custom cli commands.

Let's say I want to invoke a function every 5 seconds to post something on an external API.

In your django app create a folder/package named management inside that folder create another folder named commands. In the commands folder create a module named runposter.py. In the end you'll have something like this structure yourapp/management/commands/runposter.py.

In this code we use a thread which runs a while loop as long as it's not stopped every 5 seconds. Replace print("posting") with the function/logic you want to run.

# runposter.py
import time
from threading import Thread, Event
from django.conf import settings
from django.core.management.base import BaseCommand


stop_event = Event()


def my_job():
    while not stop_event.is_set():
        try:
            print("posting")
            time.sleep(5)
        except KeyboardInterrupt:
            break
        except Exception as err:
            print(err)
            continue



class Command(BaseCommand):
    help = "Run Poster."

    def handle(self, *args, **options):

        poster = Thread(target=my_job)

        try:
            print("Starting poster...")
            poster.start()
            while poster.is_alive():
                poster.join(timeout=1)
        except KeyboardInterrupt:
            print("Stopping poster...")
            stop_event.set()
            poster.join()
            print("Poster shut down successfully!")

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Nice, now open another terminal window and run python manage.py runposter. Command runposter as you can see was created from the module name we've given.

Of course, for something more complex I recommend using rq-scheduler or celery periodic tasks or django-q.

But, for simple cases this should be good enough.

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