Perodic Tasks By Celery 3.1 Example
Sep 01, 2014 · 2 Min Read · 1 Like · 4 Comments
This post is deprecated. It is no longer compatible with latest Celery versions.
I am assuming you have read celery docs from Celery Documentation.
As we know, celery can be used as a scheduler for executing asynchronous tasks in periodic cycles. Here I am going to share to do that with a code example. But I am going to avoid theoretical knowledge here because you can read them in celery documentation.
Install celery
First install celery: pip install django-celery.
Configuring brokers
We are using django database as Broker. For detail understanding, check here: http://celery.readthedocs.org/en/latest/getting-started/brokers/django.html
Making periodic task
Here is the project structure we are going to use:-
project
-settings.py
-manage.py
-app1
-views.py
-models.py
-app2
-views.py
-models.py
Lets say, we want to add periodic task to app1. So structure of the project will be like this:-
project
-settings.py
-manage.py
-app1
-__init__py
-celery.py
-tasks.py
-views.py
-models.py
-app2
-views.py
-models.py
No need to panic to see two new .py files. They will be created in time. 😄
Now, we need to add celery configuration in:
settings.py:-
from __future__ import absolute_import
BROKER_URL = 'pyamqp://guest:guest@wlocalhost:5672//' #read docs
CELERY_IMPORTS = ('app1.tasks', )
from celery.schedules import crontab
from datetime import timedelta
CELERYBEAT_SCHEDULE = {
'schedule-name': {
'task': 'app1.tasks.email_sending_method', # We are going to create a email_sending_method later in this post.
'schedule': timedelta(seconds=30),
},
}
As you can see, task in CELERYBEAT__SCHEDULE is name as app1.tasks.emailsendingmethod because in next section we are making a email_sendingmethod method which going to send an email every 30 seconds.
And in installed apps, we need to add djcelery :-
INSTALLED_APPS = (
...
'djcelery'
)
Now we shall add a celery.py file in app1 directory:-
from __future__ import absolute_import
import os
from celery import Celery
import django
from django.conf import settings
os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'settings')
app = Celery('app1.email_sending_method')
app.config_from_object('django.conf:settings')
app.autodiscover_tasks(lambda: settings.INSTALLED_APPS)
app.conf.update(
CELERY_RESULT_BACKEND='djcelery.backends.database:DatabaseBackend',
)
@app.task(bind=True)
def debug_task(self):
print('Request: {0!r}'.format(self.request))
and update the __init__.py file within the directory:-
from __future__ import absolute_import
from celery import app as celery_app
Now we are going to add a tasks.py which is actually going to be executed while running celery.
from __future__ import absolute_import
import datetime
from celery.task.base import periodic_task
from django.core.mail import send_mail
@periodic_task(run_every=datetime.timedelta(seconds=30))
def email_sending_method():
send_mail('subject', 'body', 'from_me@admin.com' , ['to_me@admin.com'], fail_silently=False)
Add respective credentials/configurations for sending mail, and then run this piece of code in command prompt:-
celery -A app1 worker -B -l info
And that should do the trick, we will get mails after every 30 seconds.
PS: Although there might a key-error, but it won’t occur any problems.
Last updated: Jul 13, 2024
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