Django development on Snow Leopard

02 Oct 2009
14 comments

I got my Snow Leopard in the mail lately and I decided to install it after a clean format. This gave me the opportunity to start using the new recommended Django development setup with PIP, Virtualenv and Virtualenvwrapper. While installing it all I kept a log to share with you guys (and girls). Follow along if you want to use this new found glory in Django development. We will install the following software; Mercurial, Git, PIP, Virtualenv, Virtualenvwrapper and Imaging Library

When everything is installed I will describe in short how we develop our Django site's at Bread & Pepper with all these tools.

XCode

Some of the above software must be compiled by hand and therefore we need to install XCode. You can find XCode on your Snow Leopard DVD or at the Apple developers website. Installing XCode is just a point and click operation.

Mercurial

Next we will need Mercurial for downloading the most recent versions of some of the Python packages. We will install Mercurial by hand so we don't have to use MacPorts[1]. After being a frequent user of MacPorts in the old days, I prefer compiling everything by hand these days.

Let's launch the Terminal from your Application folder and start with editing your .profile so it utilises your /url/local/ directory. I'm using Vim, so I will type in my terminal vim .profile and add the following code:

export PATH="/usr/local/bin:/usr/local/sbin:$PATH"
export PYTHONPATH=/usr/local/lib/python2.6/site-packages

Save and close the file (:wq or ZZ in Vim) and apply the new changes by typing source ~/.profile in your terminal.

We can now download and install Mercurial. First download the source in your source directory. My source directory is ~/Sources (mkdir ~/Sources if you want the same).

cd ~/Sources
curl -O http://mercurial.selenic.com/release/mercurial-1.3.1.tar.gz

And finally let's build and install.

tar xzvf mercurial-1.3.1.tar.gz
cd mercurial-1.3.1
make all
sudo make install
cd ..

We can check if Mercurial got installed successfully by typing which hg. If you get /usr/local/bin/hg than all went fine.

Git

Now let's install Git, also needed for some packages. Go to the ~/Sources folder again and do the following:

curl -O http://kernel.org/pub/software/scm/git/git-1.6.4.4.tar.bz2
tar xzvf git-1.6.4.2.tar.bz2
cd git-1.6.4.4
./configure --prefix=/usr/local
make
sudo make install
cd ..

Verify it all went as it should by checking which git. You should see /usr/local/bin/git.

PIP

PIP is a Python package manager that works well with Virtualenv because you can say in which ''Virtual Environment'' you want to install the package. You can also supply PIP with an requirements file which lists all the packages used in the project. More abouth this later, let's install it first:

sudo easy_install pip==dev

Virtualenv and Virtualenvwrapper

Virtualenv supplies you with a isolated Python environment for all your Django projects. The production version didn't work with Snow Leopard yet, so you must install the latest version from the repository. You can do that with:

sudo easy_install http://bitbucket.org/ianb/virtualenv/get/tip.zip

Virtualenvwrapper will make it easier to switch between environments. Let's install that also:

sudo easy_install virtualenvwrapper

We will need to add two lines to our ~/.profile to make it work.

export WORKON_HOME=$HOME/Sites/virtualenvs
source /usr/local/bin/virtualenvwrapper_bashrc

Make sure that WORKON_HOME is the directory where you will have your Virtual environments. After you have run source ~/.profile you can use the package by typing workon.

Imaging (PIL) with JPEG and Freetype2 support

Almost every project will make use of the Python Imaging library. To be able to use this with JPEG and Freetype2 you must have some extra libraries installed. Let's start with JPEG by going to your ~/Sources directory and typing the following commands[2]:

curl -O -L http://downloads.sourceforge.net/project/libjpeg/libjpeg/6b/jpegsrc.v6b.tar.gz
tar xzvf jpgscr.v6b.tar.gz
cd jpeg-6b
cp /usr/share/libtool/config/config.sub .
cp /usr/share/libtool/config/config.guess .
./configure --enable-shared --enable-static
make

Before installing you may need to create some extra directories.

sudo mkdir -p /usr/local/include
sudo mkdir -p /usr/local/lib
sudo mkdir -p /usr/local/man/man1

You can now install libjpg.

sudo make install

Next we need to install the Freetype2 library. This is a lot simpler.

cd ~/Sources
curl -O -L http://downloads.sourceforge.net/project/freetype/freetype2/2.3.9/freetype-2.3.9.tar.gz
tar xvfz freetype-2.3.9.tar.gz
cd freetype-2.3.9
./configure && make && sudo make install clean

Combining all the tools

You now have all those great tools installed, but what can you do with them? In this piece I'm going to describe how we work at Bread & Pepper. You will have your own worflow, but maybe you can get some tips from ours. The first thing I needed was a general Django requirements file for PIP. I have all my virtual environments in my ~/Sites/virtualenvs directory this is also the place for my base requirements file for PIP. Create a new file with vim ~/Sites/virtualenvs/django-basic-requirements.txt and fill it with the following:

# Docutils for admin documentation.
docutils

# Python Imaging Library
http://effbot.org/downloads/Imaging-1.1.6.tar.gz

# Latest Django version
-e svn+http://code.djangoproject.com/svn/django/trunk#egg=Django

Save it :wq. This file supplies us with the packages we use for every Django project. So every time we start a new project, we only have to supply this file to PIP and the rest is magic.

We now need to create a virtualenvs directory and our first Virtual Environment.

cd ~/Sites
mkdir virtualenvs
cd virtualenvs

All our Virtual enviroments will reside in this directory. Let's start building a site called magicpony.

virtualenv magicpony --no-site-packages

The above command creates a new directory called magicpony.com that is your new isolated Python environment. The --no-site-packages argument makes sure the environment is completely isolated by not inheriting the packages in your system wide $PYTHONPATH.

Now, let's install our basic Django requirements by supplying the file we created earlier (make sure you're still in the ~/Sites/virtualenvs directory) to PIP.

pip install -E magicpony.com -r django-basic-requirements.txt

This will tell PIP to install all the packages listed in the django-basic-requirements.txt file and install it in your magicpony environment. You can now activate the environment by typing:

workon magicpony.com

If all goes well, you will see (magicpony) placed in front of your prompt. If workon doesn't work, this could be because you don't have the right settings for Virtualenvwrapper inside your ~/.profile.

Let's enter our directory and create a new Django project:

django-admin.py startproject magicpony

Now when we enter the newly created directory, we can go start our Django server with ./manage.py runserver.

Another thing we do is placing a requirements.txt file inside our project directory which points to all the specific packages needed for that project. This way every new developer only has to do the following:

pip install -E magicpony -r virtualenvs/magicpony.com/magicpony/requirements.txt

And they can start working on the new project.

Conclusion

Well, it was a long ride, but now you have a top of the notch Django development setup. It certainly made our lives easier by not constantly having to make sure that the right packages were installed. We also use the requirements files for our servers so deployment (with Fabric) goes easy and secure. If you feel that I left something out, or made same errors, please do contact me.

Footnotes

1: Thanks to Dan Benjamin from Hivelogic for supplying the instructions on how to install Mercurial.

2: Thanks go out to Rich Atkinson's from Jetfar.com for the instructions.

Tags: Coding