How-To

Eclipse with the PyDev module has a lot to offer the Python programmer these days. If you haven't looked at PyDev before, or not in a while, it's worth checking out.

Editor's note: This post was originally published in September, 2010 and was updated in December, 2024 to incorporate changes in Django and improvements suggested by our readers. It has also been tested for compatibility as of the Django 4.2 release.

Deployment is usually a tedious process with lots of tinkering until everything is setup just right. We deploy quite a few Django sites on a regular basis here at Caktus and still do tinkering, but we've attempted to functionalize some of the core tasks to ease the process. I've put together a basic example that outlines local and remote environment setup. This is a simplified example and just one of many ways to deploy a Django project (I learned a lot from Jacob Kaplan-Moss' django-deployment-workshop), so I encourage you to browse around the Django community to learn more. The entire source for this example project can be found in the caktus-deployment Bitbucket repository.

Like just about everyone else, we've written our own suite of tools to help with building complex content management systems in Django here at Caktus. We reviewed a number of the existing CMSes out there, but in almost every case the navigation and page structure were so tightly coupled the system broke down when it came time to add additional, non-CMS pages.

We're always looking for new tools to make our development environment more robust here at Caktus. We write a lot of tests to ensure proper functionality as new features land and bug fixes are added to our projects. The next step is to integrate with a continuous integration system to automate the process and regularly check that status of the build.

Django's ORM is great. It handles simple to fairly complex queries right out the box without having to write any SQL. If you need a complicated query, Django's lets you use .extra(), and you can always fallback to raw SQL if need be, but then you lose the ORM's bells and whistles. So it's always nice to find solutions that allow you to tap into the ORM at different levels.

In Django, a recursive many-to-many relationship is a ManyToManyField that points to the same model in which it's defined ('self'). A symmetrical relationship is one in where, when a.contacts = [b], a is in b.contacts.

If you've ever tried to increase the shared_buffers setting in your postgresql.conf to a value that exceeds the amount of shared memory supported by your operating system kernel, then you'll see an error message like this:

Django needs a standard way in which session-specific messages can be created and retrieved for display to the user. For years we’ve been surviving using user.message_set to store messages that are really specific to the current session, not the user, or using the latest and greatest Django snippet, pluggable app, or custom crafted middleware to handle messages in a more appropriate way.

As part of my work on EveryWatt, our fledgling energy monitoring web site, I needed a way to consolidate log messages from all the data loggers we have running in a single place. If you're not familiar with it, Python's logging module is good stuff and worth checking out. We already used it for logging to files locally, and the module defines an HTTPHandler that can deliver log messages to a remote server via HTTP.