django框架的运行流程（django cron choice）

时间2025-06-20 23:55:21分类IT科技浏览4089

导读：http://stackoverflow.com/questions/3200001/using-crontab-with-django...

http://stackoverflow.com/questions/3200001/using-crontab-with-django

Kronos

Kronos makes it really easy to schedule tasks with cron.

Usage

Define tasks

Kronos collects tasks from cron modules in your project root and each of your applications:

# app/cron.py import kronos @kronos.register(0 0 * * *) def complain(): complaints = [ "I forgot to migrate our applicationss cron jobs to our new server! Darn!", "Im out of complaints! Damnit!" ] print random.choice(complaints)

Run tasks manually

$ python manage.py runtask complain I forgot to migrate our applicationss cron jobs to our new server! Darn!

Register tasks with cron

$ python manage.py installtasks Installed 1 task.

Installation

$ pip install django-kronos

... and add kronos to INSTALLED_APPS.

Contribute

Fork the repository. Do your thing. Open a pull request. Receive cake.

I love you

Johannes Gorset made this. You should tweet me if you cant get it

to work. In fact, you should tweet me anyway.

slowchop.com

http://slowchop.com/2006/09/17/creating-a-django-cron-job/

http://goo.gl/ffgS

iReader

import urllib2 from models import WebSite def daily_job(): for site in WebSite.objects.all(): page_html = urllib2.urlopen(site.url).read() do_something_with_page_html(page_html) #!/usr/bin/env python from mytestapp.views import daily_job daily_job()

EnvironmentError: Environment variable DJANGO_SETTINGS_MODULE is undefined.

#!/usr/bin/env python import os os.environ[DJANGO_SETTINGS_MODULE] = settings from mytestapp.views import daily_job daily_job() import sys import os os.environ[DJANGO_SETTINGS_MODULE] = settings module_name = sys.argv[1] function_name = .join(sys.argv[2:]) exec(import %s % module_name) exec(%s.%s % (module_name, function_name)) python run.py mytestapp.views daily_job() 0 0 * * * python /path/to/mytestproject/run.py mytestapp.views daily_job()

Chronograph

Control django-admin commands via the web.

Creating cron jobs for Django apps can be a pain, annoying and repetitive. With

django-chronograph

you simply create a single cron job to run every minute,

point it at your sites directory and run manage.py cron. Then from the admin

you can add jobs.

Note

django-chronograph supports Django 1.1+.

Installation and Usage

Read docs/overview.txt for more information, build the documentation with

Sphinx or view them online here.

You can also grab the latest release from PyPI:

pip install django-chronograph

Scheduled Tasks (or cron jobs) with Django

This is my take on setting up cron jobs for the apps in a Django project. It is based on my own convention, and it solves my initial problems where I want to perform some action on all of my Django apps at a periodic interval (currently this is a once-a-day task).

In order for this to work, I create a cron.py module for all of my INSTALLED_APPS. This module must contain a run method. Other than that, it can work just like any other python module (using djangos internals as necessary).

For example, if you had an app called utils (possibly located at mysite/utils/), and if you just wanted to delete all sessions with old expire_dates, your cron.py (which you would put in mysite/utils/cron.py) might look something like this:

from datetime import datetime from django.contrib.sessions.models import Session def delete_old_sessions(): Session.objects.filter(expire_date__lt=datetime.now()).delete() def run(): delete_old_sessions()

Now, the meat of this solution checks for the cron.py module in all of the apps in mysite.settings.INSTALLED_APPS, and invokes its run() method. Ive also named this module cron.py, but this gets stored in Djangos project directory (e.g. mysite)... the same directory where your settings.py is located.

#!/usr/bin/env python """ Project-wide Cron Job... A Command-line Django Script. This script gets scheduled and run by cron (or whatever). It then calls the `run` method of each apps cron module, if it exists (should be `appname/cron.py`) This script should be invoked after setting the DJANGO_SETTINGS_MODULE environment variable. You chould do this in a BASH script as follows: export DJANGO_SETTINGS_MODULE=mysite.settings python /path/to/mysite/cron.py """ from django.conf import settings def my_import(name): __import__ helper function to import modules inside packages e.g.: where name is something like package.module.mod_i_want, would return mod_i_want See: http://www.python.org/doc/2.5.2/lib/built-in-funcs.html mod = __import__(name) components = name.split(.) for comp in components[1:]: mod = getattr(mod, comp) return mod def run(): for app in settings.INSTALLED_APPS: if not app.startswith(django): output_info = %s.cron%app ## Dynamically import a module called cron ## from each INSTALLED_APP (if it exists) try: cron_mod = my_import(app+.cron) output_info += ... FOUND print output_info ## 3. Execute the crons run method (if it exists) if hasattr(cron_mod, run): #print ---> calling run() cron_mod.run() except ImportError: # ignore packages that dont have a cron module output_info += ... SKIPPED print output_info if __name__ == "__main__": run()

The final piece of this puzzle lies in the BASH script used to invoke the above python module. It makes sure the appropriate environment variables are set and then it invokes the above module. I also store this in my django project directory (as cron.sh), and I use cron to schedule it to run.

#!/bin/bash # This is a Django, Project-specific Cron script. # Separate Projects would need a copy of this script # with appropriate Settings export statments. PYTHONPATH="${PYTHONPATH}:/path/to/django/project/directory" export PYTHONPATH export DJANGO_SETTINGS_MODULE=mysite.settings python/path/to/django/project/directory/mysite/cron.py

Using cron, youd schudule this to run every morning at 6am by editing your crontab and adding the following:

#m h dom mon dow command 0 6 * * * /path/to/django/project/directory/cron.sh

Thats it. This has been working for me, but there is at least one major pitfall: All of your apps cron tasks get run at the same time. This works well if your apps need to do something once a day (which has been my requirement), but this probably wont work well if you have some apps that need to run tasks at differing times.

There are also other solutions to this (none of which Ive tried). Theres a snippet at http://www.djangosnippets.org/snippets/1126/ which looks interesting. Then theres the django-cron app which seems to be fairly flexible in how it works, and it doesnt require cron (so this is a plus if you cant set a crontab or if youre on Windows!)

Thanks in advance for any feedback... suggestions are always welcome!

声明：本站所有文章，如无特殊说明或标注，均为本站原创发布。任何个人或组织，在未征得本站同意时，禁止复制、盗用、采集、发布本站内容到任何网站、书籍等各类媒体平台。如若本站内容侵犯了原著者的合法权益，可联系我们进行处理。