Interactive debugging in Django

A long time ago in a galaxy far far away... programmers were debugging PHP applications using the echo function. Well it actually wasn't that long ago nor was the galaxy far away - we're talking about the late 90'; planet Earth.

Nowadays it is rather unthinkable, time is money and spending whole days placing and removing echo's is expensive (not mention ineffective). So how to efficiently debug Django views?

The first thing you need to do is set the following variable in settings.py:
   
   DEBUG = True
 
This option is enabled by default. If it is set, each time a view returns a HTTP 500 Internal Server Error, a debug view will be presented. It contains your current settings, request parameters and finally a stack trace - usually this is enough to solve most problems.

If it is not enough you may want to try the second option: pdb the standard python debugger tool. To insert a break point you should put the following line in your code and start the application via runserver:

    import pdb ; pdb.set_trace()

If you master the short-cut commands this is a very pleasant tool. You can also check out the interactive version ipdb (requires ipython).

However if you do not feel like debugging in the console, or you want to have access to the whole stack trace without inserting hundreds of break-points - werkzeug is the tool for you! It is an awesome interactive JavaScript based in-browser debugger. You can get it with pip (along with dependencies):

~ pip install django-admin-tools
~ pip install werkzeug

Now, instead of using the runserver command, you use the following:

~ ./manage.py runserver_plus

After this, each time you encounter an exception debug view appears... however this is no ordinary Django debug view, it contains an in-browser debugger like pdb which is capable of jumping between every point of the stack trace. This is just great, if I could also integrate vim with FireFox aswell... *kidding* :-)

~KR