Django-Celery Scheduling Daily Tasks on Windows Server

Question

I have to schedule a task to run every Monday through Saturday. I downloaded django-celery to accomplish the task. I followed the tutorial on the Celery site and I used and looked at a few stack overflow posts, for example: here & here

I did a mix and match with the above posts and with this two great tutorials: Rhatore and Freitas

This is my folder structure:

Application
    | apps
         | app1
              | __init__.py
              | tasks.py
              | urls.py
              | views.py    
    | Application
         | __init__.py
         | celery.py
         | settings.py
         | urls.py
         | wsgi.py

Settings.py

INSTALLED_APPS = [
    'django_celery_beat',
    'apps.app1',
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
]

LANGUAGE_CODE = 'en-us'
TIME_ZONE = 'UTC'
USE_I18N = True
USE_L10N = True    
USE_TZ = True

CELERY_BROKER_URL = 'amqp://localhost'
CELERY_RESULT_BACKEND = 'amqp://localhost'
CELERY_ACCEPT_CONTENT = ['application/json']
CELERY_TASK_SERIALIZER = 'json'
CELERY_RESULT_SERIALIZER = 'json'
CELERY_TIMEZONE = 'UTC'

__init__.py In the init under the Application

from __future__ import absolute_import, unicode_literals
from .celery import app as celery_app

from .celery import app as celery_app

    __all__ = ('celery_app',)

celery.py

from __future__ import absolute_import, unicode_literals
import os
from celery import Celery

os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'Application.settings')

app = Celery('Application')

app.config_from_object('django.conf:settings', namespace='CELERY')
app.autodiscover_tasks()

@app.task(bind=True)
def debug_task(self):
    print('Request: {0!r}'.format(self.request))

tasks.py - for simplicity sake I reduced the task to a simple print command

from celery import shared_task
from celery.utils.log import get_task_logger
from celery.schedules import crontab
from celery.task import periodic_task
from celeryapp.emails import send_feedback_email
from django.http import HttpResponse
from .models import *

logger=get_task_logger(__name__)

@periodic_task(run_every=crontab(hour=21, minute=32, day_of_week=0-5))
def simple_print():
    print("Hello World!")

I ran:

celery -A Application -1 info

And then python manage.py runserver 21:32 UTC passed and it did not print. I expected to see "Hello World" printed at 21:32 UTC in the terminal as per the task specified in tasks.py. It did not print.

I also ran:

celery -A Application worker -l info
celery -A Application beat -l info
python manage.py runserver

in different terminals. It did not execute the task.

Guidance would be much appreciated.

Can you explain your problem in more detail. Or maybe "it did not print" - is an explanation of problem? What did you expect? — Alex Yu, Feb 15 '19 at 22:03
Alex thank you for your question. I edited my question. Basically, what I'm trying to do is to print "Hello World" to the terminal using a cron. — L. P., Feb 15 '19 at 22:15
If you substitute `print` with file-`write` or `logging.info` or maybe database insert - would you get "Hello World!"? — Alex Yu, Feb 15 '19 at 22:21
I tried f = open("myfile.txt", "x") and it didn't create a file. — L. P., Feb 15 '19 at 22:46

score 1 · Answer 1 · answered Feb 15 '19 at 22:58

1

You need to have both the worker and the beat running, so that celery will know if it has to run a periodic task at a certain time.

Something like this should help you in your local environment.

celery -A Application worker -l info -B

Alternatively, you can start both workers as individual services

celery -A Application worker -l info

celery -A Application beat -l info

answered Feb 15 '19 at 22:58

Alex

2,356
15
19

I tried to use -B and it's saying that -B does not work on Windows. How do I run them individually? Different terminals? Can I be in any directory or do I need to be in the app directory? When do I run manage.py runserver before or after starting the workers? Does it have to be in another terminal window? – L. P. Feb 15 '19 at 23:07
3 terminals / tmux sessions: one for celery worker, one for beat and then one for runserver. – Alex Feb 15 '19 at 23:09
I opened 3 windows. Navigated to the Application folder on each of them. Ran the worker, beat, and python manage.py runserver and it did not print. – L. P. Feb 15 '19 at 23:16
Might be a problem with timezones or missing configuration. It's pretty tedious debugging without a stacktrace or something else than brief descriptions. – Alex Feb 15 '19 at 23:20

L. P. · Accepted Answer · 2019-08-19T13:15:32.370

The code was correct. The problem was due to the OS. I'm using Windows and Celery 4.0 does not support Windows. This question was very useful: How to Run Celery on Windows. I installed gevent and it worlks now.

pip install gevent
celery -A Application beat -l info
celery -A Application worker -l info -P gevent

If you get another error along the lines of "Fatal error in launcher..." try:

python -m celery -A Application beat -l info
python -m celery -A Application worker -l info -P gevent

Django-Celery Scheduling Daily Tasks on Windows Server

2 Answers2