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.

Thursday, July 12, 2012

PyCharm for Django development

I have been dabbling with Django for a few years now. Previously, I always used Eclipse for this. Eclipse by itself doesn't support Python or Django but add PyDev or Aptana Studio and it merrily understands what is going on. This was great when I worked on multiple projects in multiple languages. I now find myself working solely in a Python/Django environment. PyCharm was getting rave reviews from my former work colleagues, but I did so little Django it didn't seem worth making the transition. However, with a new role I thought now was the time and I haven't looked back. If you have ever used IntelliJ IDEA for Java you'll be familiar with PyCharm as it is built upon the same framework. Being written in Java also means you are able to code on your Mac, Linux and Windows devices.

For once PyCharm is fully aware of Django, not just syntax highlighting (which was also hit and miss especially in templates mixing HTML/CSS/Django template syntax in Eclipse).  Truth be told I have barely touched the surface of features that PyCharm packs in. See http://www.jetbrains.com/pycharm/features/index.html for a full run down. Each release, of which updates are frequent, either refine or add more features. In the 2.5 release virtualenv support was added, it worked with manual intervention before, but now PyCharm automatically detects them. In addition the support at JetBrains is superb. Admittedly this is a commercial product, although they license favorably for open source project - free.

Just like IntelliJ various plugins are available. A whole host ship by default, Git, CoffeeScript and JavaScript to name a few. More are available online at the plugin repository. The nginx support and NodeJS plugins caught my eye.

One of my favorite features is suport for running mange.py tasks from within the IDE, no need to setup the environment and run from there, as shown (image courtesy of JetBrains).

In fairness I did look at other Python IDEs with Django support, but feel they fall into the same camp as Eclipse. The Django support is just tacked on and is limited. With PyCharm you can see Django support was core to the design and features implemented. I see the PyCharm team will be at DjangoCon US. This is great for two reasons a) I can congratulate them on a great IDE and b) they will be bring a new update (http://blog.jetbrains.com/pycharm/2012/06/pycharm-at-djangocons-around-the-world/).