yet-another-django-profiler 0.2.0

Django middleware for performance profiling directly from the browser

Yet Another Django Profiler attempts to combine the best features of assorted other Django profiling middleware classes that have been created over the years. (For more background information, see my blog post on the topic.)

Installation

First, get the code via pip install:

pip install yet-another-django-profiler

Then add yet_another_django_profiler.middleware.ProfilerMiddleware to your MIDDLEWARE_CLASSES Django setting (typically at the end of the list, if you want to include profiling data on the other middleware that’s in use). If you want to generate call graphs with the middleware, you also need to install Graphviz.

Usage

The simplest usage is to just add a profile parameter to the URL of a Django view. This uses Graphviz to generate a PDF representation of the call graph for the code executed to perform the view, and returns that as the response to the request instead of the rendered view itself. So calling a URL like http://localhost:8000/admin/?profile shows a PDF like this in the browser.

Alternatively, you can display a table of called functions ordered by the desired statistic by using a URL such as http://localhost:8000/?profile=time. The available sorting options are:

• calls (call count)

• cumulative (cumulative time)

• file (file name, same as module)

• module (file name, same as file)

• pcalls (primitive call count)

• line (line number)

• name (function name)

• nfl ( function name/file/line)

• stdname (standard name)

• time (internal time)

By default, only the top 20% of function calls are included in the table. To change that, add a fraction parameter with the desired display ratio (hence the default value is fraction=.2). Alternatively, you can instead specify a maximum number of function calls to display using the max_calls parameter. And if you specify a regular expression with the pattern parameter, only calls of functions whose names match the specified pattern will be displayed. (I’d recommend sticking to basic sub-strings unless you really enjoy figuring out how to URL-escape special characters.)

If you forget the available sorting options and such, you can use profile=help as a request parameter to display the usage instructions in the browser.

Settings

The middleware is designed to be available whenever the DEBUG setting is True, and removes itself from the middleware chain otherwise (so it can safely be left in the dependencies for production deployments without performance or security problems). If for some reason you want to change this behavior, you can set the YADP_ENABLED boolean setting directly to determine whether the middleware is active or not.

If you have pages where the default profiling parameter names conflict with existing parameters in the application, you can choose different ones via the following settings:

• YADP_PROFILE_PARAMETER (default is “profile”)

• YADP_FRACTION_PARAMETER (default is “fraction”)

• YADP_MAX_CALLS_PARAMETER (default is “max_calls”)

• YADP_PATTERN_PARAMETER (default is “pattern”)

In order to get simple and meaningful profiling data, a few other changes to your settings may be in order.