Tuesday, July 17, 2012

Using Gunicorn with PyCharm

The Green Unicorn
When you develop projects with Django it comes with a handy runserver which is a lightweight webserver bundled with Django, see more here. It goes without saying you would never want to deploy any production code with this as it doesn't scale nor is it particularly secure. It does not get much attention from the Django developers, lets face it there are better things to work on. So a few alternatives have popped up. The one which caught my eye is gunicorn. Now gunicorn can be used on preprod or production sites as well, but I stick to development here (what I use for production will feature in another post).

Gunicorn is actually a fork of Unicorn which is designed for use with Ruby. It is a WSGI webserver, WSGI is the way to run webservers. It also features integration with Django so can be a drop in replacement for runserver. Installation is a breeze, pip install gunicorn and add gunicorn to your INSTALLED_APPS in your settings.py - Easy.

From the command-line you might do ./manage.py runserver with the Django runserver. To use Gunicorn simply run ./manage.py run_gunicorn Again straight forward. Within PyCharm you need edit your django run configuration and tick the "run custom command" box. Add run_gunicorn and run that. run_gunicorn is a helper function that gunicorn adds to manage.py. Unfortunately, I found not all gunicorn options can be specified via this, which can be annoying.  To access all gunicorn options you need to run gunicorn direct and feed it a wsgi application, handily django is wsgi ready and from 1.4 includes a wsgi file when you create a new project (look for wsgi.py in your project directory). When using gunicorn direct you do not need to list gunicorn in your INSTALLED_APPS. From your virtualenv run gunicorn -b myproject.wsgi:application, where myproject is your Django project name. You can drop in any gunicorn options you like as well. As for running in PyCharm you need to create a Python run configuration, not Django, and provide the following information:

  1. Script - /Users/craig/.virtualenvs/blogenv/bin/gunicorn (your virtualenv of choice)
  2. Script parameters: -b myproject.wsgi:application
  3. Working directory: /Users/craig/PycharmProjects/MyDjangoApp
There is another reason to use gunicorn directly - you can use it with supervisor.

You may come across the gunicorn_django application as well. That is fine to use if you are not on Django 1.4, otherwise use the gunicorn application direct, as shown above.

There is also devserver from David Cramer. I've not used it personally but the other projects that David works on are top rate, so I imagine this is too.