Ubuntu 10.04, Django and GAE - Part 2

Published on Saturday, June 12, 2010

All my Django sites are running 1.2, which poses a conflict with writing apps for Google's App Engine, as use_library currently only supports < Django 1.1. There are two solutions that I found: a) use virtualenv, or b) chroot, which I've already detailed. This document will hopefully show you how to create a virtual environment to use a secondary django version, especially for GAE. Of the two options, I think this one is a bit quicker, but there will likely be tradeoffs that a chroot environment can deal with better, e.g. python imaging (I don't use it for GAE).
First, install PIP and virtualenv:
kelvinn@kelvinn-laptop:~/workspace$ sudo easy_install -U pip
kelvinn@kelvinn-laptop:~/workspace$ sudo pip install -U virtualenv

Second, configure an environment for any app that will use Django 1.1:
kelvinn@kelvinn-laptop:~/workspace$ virtualenv --python=python2.5 --no-site-packages django-1.1
New python executable in django-1.1/bin/python
Installing setuptools............done.
kelvinn@kelvinn-laptop:~/workspace$ pip install -E django-1.1 yolk
kelvinn@kelvinn-laptop:~/workspace$ pip install -E django-1.1 Django==1.1

Now, download the python GAE sdk and put it in the django-1.1 folder. I also just dump any project directory requiring Django 1.1 into this django-1.1 folder, although I guess you could create a virtualenv for each project. The last thing to do is start the virtual environment, and run the GAE app.
kelvinn@kelvinn-laptop:~/workspace$ source django-1.1/bin/activate
(django-1.1)kelvinn@kelvinn-laptop:~/workspace$ yolk -l
(django-1.1)kelvinn@kelvinn-laptop:~/workspace$ cd django-1.1
(django-1.1)kelvinn@kelvinn-laptop:~/workspace/django-1.1$ ls
bin  google_appengine  include  lib  myproject1 myproject2
(django-1.1)kelvinn@kelvinn-laptop:~/workspace/django-1.1$ google_appengine/dev_appserver.py myproject1

When you're all finished, you can jump out of virtualenv:
(django-1.1)kelvinn@kelvinn-laptop:~/workspace/django-1.1$ deactivate

Update: You'll find this article especially interesting if you get an error such as the following:
UnacceptableVersionError: django 1.1 was requested, but 1.2.0.beta.1 is already in use

Ubuntu 10.04, Django and GAE - Part 1

Published on

I've started to get into Google's App Engine again, and have started developing a simple product that I had a use for. The initial first draft was a quick 200 lines in webapp, and it worked great. However, I'm starting to find certain things quite cumbersome. I'm a huge fan of Django, and but also about keeping things as simple as possible, which is why I picked webapp to begin with.
I'm now considering making a swap to Django, but there are some development issues; namely, I'm using Ubuntu 10.04, Python 2.6, and Django 1.2. This setup presents several setbacks, as GAE has the requirement of Django 1.1 and Python 2.5. There are two solutions that I found: a) use virtualenv, which I've detailed, or b) chroot. This document will hopefully show how to configure a chroot environment of Ubuntu 9.10 and prepare it for Django on GAE. Using a jailed environment should allow you to edit your code with your normal IDE and VCS, but use Django 1.1 and Python 2.5.
First, I installed schroot and debootstrap.
$ sudo apt-get install schroot debootstrap

Second, I edited /etc/schroot/schroot.conf and added the following section to the end.
users=kelvinn #your username goes here

Third, I created the directories needed for the jailed environment and installed karmic.
$ sudo mkdir -p /var/chroot/karmic
$ sudo debootstrap --arch i386 karmic /var/chroot/karmic 

Forth, I logged into the jailed environment and updated packages, installed Python 2.5 / Django 1.1. Make sure to note that I don't call 'python', I call 'python2.5'.
$ sudo schroot -c karmic
(karmic)root@kelvinn-laptop:~# apt-get update
(karmic)root@kelvinn-laptop:~# apt-get install python2.5
(karmic)root@kelvinn-laptop:~# cd /usr/src
(karmic)root@kelvinn-laptop:~# apt-get install wget
(karmic)root@kelvinn-laptop:/usr/src# wget http://www.djangoproject.com/download/1.1.2/tarball/
(karmic)root@kelvinn-laptop:/usr/src# tar -xpzf Django-1.1.2.tar.gz
(karmic)root@kelvinn-laptop:/usr/src/Django-1.1.2# python2.5 setup install
(karmic)root@kelvinn-laptop:/usr/src/Django-1.1.2# exit

Lastly, I log in as my normal user, and start the app. Let's say I have a folder called '~/gaeapps' for my GAE stuff, and that's where I put the SDK.
$ scroot -c karmic
(karmic)kelvinn@kelvinn-laptop:~/gaeapps$ ls
google_appengine  myproject
(karmic)kelvinn@kelvinn-laptop:~/gaeapps$ google_appengine/dev_appserver.py myproject