Ubuntu – How to install Django for Python 3.x


I installed Django with this command:

sudo apt-get install python-django

And it installed version 1.5.4-1ubuntu1. The Django docs say that as of version 1.5, Django supports Python 3. Yet when I run the python 3 interpreter and try importing Django, it says there's no such module. I tried looking for a python3 version of Django, but no such package exists. How can I get django working on python3? I'd prefer to use ubuntu packages instead of installing things manually.

Best Answer

I would strongly suggest avoiding pip3 to install things in the system site-packages. I've made these arguments before but I'll give you the notes:

  • System updates break everything
  • Installing apt packages can overwrite pip-installed things
  • Version conflicts
  • Distribution upgrades are unpredictable chaos. Seriously. I've lost hair to these.

I would strongly advocate using virtualenv. It's a massive pain in the wherever to get going but once you've got it set up you have a complete Python environment under your complete control. This does mean more work (you'll have to check things for updates and pip doesn't really help there yet) but you don't have to worry about what Ubuntu's doing.

I have an environment for each site (just sitting in a subdirectory called venv). Some people —including me, once upon a time— prefer to share their environments between multiple sites. I found this easier to maintain in terms of issuing updates but some sites can be fragile or require old versions and that holds the whole environment back. YMMV.

In terms of installing this, and just to slap me in the face, virtualenv isn't packaged for Python 3 yet so we have to use pip3:

$ sudo pip3 install virtualenv

$ virtualenv-3.3 myenv
Using base prefix '/usr'
New python executable in myenv/bin/python3
Also creating executable in myenv/bin/python
Installing setuptools, pip...done.

$ source myenv/bin/activate  # This is important!

Your bash PS1 should now be preneded with (myenv) to let you know you're in a different environment. We can test the environment to check we're on the right versions of things (not using the system versions for starters):

$ python --version
Python 3.3.2+
$ which python pip 

And then you can just carry on as if you were master of the universe. You don't need root to use pip anymore and you don't need to specify pip3. It's just a lot more friendly.

$ pip install django umemcache

If you're using something like uwsgi to host this (you should) use its -H flag (or home config argument) to tell it where the Python environment lives.

As for making development easier, you can automatically "mount" your virtualenv environment. There are many scripts out there but this one is mine (this lives at the bottom of my ~/.bashrc:

export VENVDIR="/web"

venvcd() {
        [[ $wd == $VENVDIR/* || $wd == $VENVDIR ]] && wasin=true || unset wasin

        builtin cd "$@"

        if [[ $wd == $VENVDIR/* || $wd == $VENVDIR ]]; then
                source $VENVDIR_VENV/bin/activate
                [ $wasin ] && deactivate
alias cd="venvcd"

cd .

Whenever I cd into /web (where all my development websites are stored), it mounts the virtualenv for me. Note that I only have one environment for all my sites so this will only suite you if you do something similar. There are many other ways of doing similar things.

Related Question