How would you process tasks in django, say there is an event only to processed once daily, weekly, monthly. (besides cron)
What do you mean, besides cron? cron is exactly how you would do it.
http://celeryproject.org/
You can also use a very simple tool: django-cron (runs inside of Django application thread).
If you do this please see my answer: Django: Getting Django-cron Running
Related
In my admin I have a form allowing to upload a file to fill the DB.
Parsing and filling the DB take a long time, so I'd like to do it asynchronously.
As recommended by several SO users I tried to install python-celery, but I can't manage to do it (I'm on Webfaction).
Is there any simple, easy-to-install alternative?
If webfaction supports cron jobs you can create your own pseudo broker. You could save your long running tasks to the db and in a 'tasks' table, this would allow you to return a response to the user instantaneously. Then there could be a cron that goes through very frequently and looks for uncompleteled tasks and processes them.
I believe this is what django mailer does
https://github.com/jtauber/django-mailer/
https://stackoverflow.com/a/1419640/594589
Try Gearman along with it's python client library
It's very easy to setup and run gearman. Try few examples.
I am implementing a feature in a new project and I was wondering what was the optimal solution to it. The feature itself consists of sub functionality as follows: starting a process, stop a process, and checking if the process is running...all these done in a non-blocking way with django. I am trying to avoid stuff like RabbitMQ, etc. I was thinking maybe of using threading or cron.
EDIT: these functionality need to be triggered from a view.
Any comments or suggestions are the most welcomed. Thanks.
You can surely use celery with the database backend instead of RabbitMQ. Personally, for simple tasks I tend to just write a custom mangement command launched from cron, that gets its input from some database table (i.e. Django model) which is populated by Django view(s).
I'm building a simple website with django that requires constant monitoring of text-based data from another website, that's the way it have to be.
How could I run this service on my web-host using django? would I have to start a separate app and run it via SSH, so it updates the database used by django, or are there any easier/better way?
You could use celery to schedule a job that would read data from that other website and do whatever you want with it.
As an alternative to celery, you could also create a cron job that executes a custom django-admin command. That would give you full access to your django install and ORM. The downside is that cron's smallest time resolution is 1 minute, so if you need it to be real-time, you're not going to be able to do that.
If you do need realtime, then creating a python daemon might be a better option.
How to make Django execute something automatically at a particular time.?
For example, my django application has to ftp upload to remote servers at pre defined times. The ftp server addresses, usernames, passwords, time, day and frequency has been defined in a django model.
I want to run a file upload automatically based on the values stored in the model.
One way to do is to write a python script and add it to the crontab. This script runs every minute and keeps an eye on the time values defined in the model.
Other thing that I can roughly think of is maybe django signals. I'm not sure if they can handle this issue. Is there a way to generate signals at predefined times (Haven't read indepth about them yet).
Just for the record - there is also celery which allows to schedule messages for the future dispatch. It's, however, a different beast than cron, as it requires/uses RabbitMQ and is meant for message queues.
I have been thinking about this recently and have found django-cron which seems as though it would do what you want.
Edit: Also if you are not specifically looking for Django based solution, I have recently used scheduler.py, which is a small single file script which works well and is simple to use.
I've had really good experiences with django-chronograph.
You need to set one crontab task: to call the chronograph python management command, which then runs other custom management commands, based on an admin-tweakable schedule
The problem you're describing is best solved using cron, not Django directly. Since it seems that you need to store data about your ftp uploads in your database (using Django to access it for logs or graphs or whatever), you can make a python script that uses Django which runs via cron.
James Bennett wrote a great article on how to do this which you can read in full here: http://www.b-list.org/weblog/2007/sep/22/standalone-django-scripts/
The main gist of it is that, you can write standalone django scripts that cron can launch and run periodically, and these scripts can fully utilize your Django database, models, and anything else they want to. This gives you the flexibility to run whatever code you need and populate your database, while not trying to make Django do something it wasn't meant to do (Django is a web framework, and is event-driven, not time-driven).
Best of luck!
In my django project I would like to be able to delete certain entries in the database automatically if they're too old. I can write a function that checks the creation_date and if its too old, deletes it, but I want this function to be run automatically at regular intervals..Is it possible to do this?
Thanks
This is what cron is for.
You will be better off reading this section of the Django docs http://docs.djangoproject.com/en/1.2/howto/custom-management-commands/#howto-custom-management-commands
Then you can create your function as a Django management command and use it in conjunction with cron on *nix (or scheduled tasks on Windows) to run it on a schedule.
See this for a good intro guide to cron http://www.unixgeeks.org/security/newbie/unix/cron-1.html
What you require is a cron job.
A cron job is time-based job scheduler. Most web hosting companies provide this feature which lets u run a service or a script at a time of your choosing. Most Unix-based OSes have this feature.
You would have better direct help asking this question on serverfault.com, the sister site of stackoverflow.