What's this for

We were looking for profiling tools as we worked on improving the performance of one of our Django applications. We didn't find anything that tripped our triggers so this was created.

It's some tooling, right now Middleware and a decorator, that allows you to quickly see some profile data and optionally export a .kgrind file suitable for viewing in KDE's KCacheGrind.

Installation

You need Django for this to work, if you need help with that head here

Using Pip:

pip install django-depiction

Or:

pip install -e git+http://github.com/robmadole/django-depiction.git#egg=djangodepiction

Settings

Edit your Django settings, adding this to the MIDDLEWARE_CLASSES.

MIDDLEWARE_CLASSES = (
    ...
    'depiction.middleware.ProfilerMiddleware',
)

Add the following setting

PROFILING = True

And make sure that your internal IP address is present

INTERNAL_IPS = ('127.0.0.1',)

Middleware usage

You can trigger output by adding prof to the query string. For example, say this was a URL in your application

http://127.0.0.1:8000/lumberjacks/list

To get some profile data on this page

http://127.0.0.1:8000/lumberjacks/list?prof

If you already have a query string, add to it like this

http://127.0.0.1:8000/lumberjacks/list?playsDressup=True&prof

To filter by filename

http://127.0.0.1:8000/lumberjacks/list?playsDressup=True&prof=django/template

To get your profile data as a kgrind file

http://127.0.0.1:8000/lumberjacks/list?prof&grind

Note You will need to make sure prof is also set. This will trigger a "Save As.." file download of the profile data to use in KCacheGrind.

Creating kgrind files

There is a project called KCacheGrind that provides a GUI for analyzing profile data. You are on your own to get KCacheGrind installed, but once you do you will need a .kgrind file to look at.

You can do this with a decorator. Here is a Django View example.

from django.template.loader import render_to_response
from depiction.decorator import kgrind

from lumberjacks.models import *


@kgrind('listing_lumberjacks.kgrind')
def list_lumberjacks(request):
    return render_to_response('lumberjacks/list.html', {
        men': Lumberjacks.objects.all()})

This will create a listing_lumberjacks.kgrind file in the current working directory. You can then load this into KCacheGrind.

Credits

This was mostly inspired by David Cramer's Middleware. He get's most of the credit for the idea and seed of the code we wrote.

Here is the Middleware snippet

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