Django Celery Scheduling a manage.py command

Question

I need to update the solr index on a schedule with the command:

(env)$ ./manage.py update_index

I've looked through the Celery docs and found info on scheduling, but haven't been able to find a way to run a django management command on a schedule and inside a virtualenv. Would this be better run on a normal cron? And if so how would I run it inside the virtualenv? Anyone have experience with this?

Thanks for the help!

Answer 1

To run your command periodically from a cron job, just wrap the command in a bash script that loads the virtualenv. For example, here is what we do to run manage.py commands:

django_cmd.sh:

#!/bin/bash

cd /var/www/website/
source venv/bin/activate
/var/www/website/manage.py $1 --settings=$2

Crontab:

MAILTO=webmaster@website.com
SETTINGSMODULE=website.settings_prod
5 * * * * /var/www/website/django_cmd.sh update_index $SETTINGSMODULE >> /dev/null
0 10 * * * /var/www/website/django_cmd.sh update_accounts $SETTINGSMODULE 

Answer 2

Django Celery Task Scheduling project structure

[appname]/
├── [appname]/
│   ├── __init__.py
│   ├── settings.py
│   ├── urls.py
│   ├── celery.py
│   └── wsgi.py
├── [project1]/
│   ├── __init__.py
│   ├── tasks.py
│   
└── manage.py

add below configuration in settings.py file:

STATIC_URL = '/static/'
BROKER_URL = 'redis://localhost:6379/0'
CELERY_ACCEPT_CONTENT = ['application/json']
CELERY_TASK_SERIALIZER = 'json'
CELERY_RESULT_SERIALIZER = 'json'
CELERY_RESULT_BACKEND = 'redis'
from celery.schedules import crontab
CELERY_TIMEZONE = 'UTC'

celery.py : holds celery task scheduler

from __future__ import absolute_import, unicode_literals
import os
from celery import Celery
import django
# set the default Django settings module for the 'celery' program.
os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'appname.settings')
from django.conf import settings
app = Celery('appname')
app.config_from_object('django.conf:settings')
app.autodiscover_tasks()
@app.task(bind=True)
def debug_task(self):
    print('Request: {0!r}'.format(self.request))
**#scheduler**
app.conf.beat_schedule = {
    'add-every-30-seconds': {
        'task': 'project1.tasks.cleanup',
        'schedule': 30.0,
        'args': ()
    },
}
app.conf.timezone = 'UTC'

init.py

from __future__ import absolute_import, unicode_literals

# This will make sure the app is always imported when
# Django starts so that shared_task will use this app.
from .celery import app as celery_app

__all__ = ['celery_app']

tasks.py from project1

from celery import shared_task
import celery
import time
from django.core import management
@celery.task#(name='cleanup')
def cleanup():
    try:
        print ("in celery module")
        """Cleanup expired sessions by using Django management command."""
        management.call_command("clearsessions", verbosity=0)
        #PUT MANAGEMENT COMMAND HERE
        return "success"
    except:
        print(e)

Task will run after every 30 seconds

Requirement fro windows:

1. redis server should be running

2. celery worker and celery beat should be running run each below command on different terminal

   celery -A appname worker -l info

   celery -A appname beat -l info

Requirement fro Linux:

1. redis server should be running

2. celery worker and celery beat should be running celery beat and worker can be started on same server

   celery -A appname worker -l info -B

@tzenderman please let me know if I missed something. For me this is working fine

Answer 3

I actually found a nice way of doing this using fabric + celery and I'm working on it now:

In app/tasks.py, create a fabric function with the manage.py commands you need, then decorate it with @periodic_task, add it to your celery schedule and it should be good to go.

UPDATE: I wasn't able to actually use Fabric + Celery because using fabric in the module caused it be recognized as a fabric file and the celery calls in the file didn't work.