Sunday, 6 November 2011

Google App Engine Python2.5 Development in Ubuntu 11.10

How to set up a development environment for Google App Engine, Python2.5 in Ubuntu 11.10.
Firstly, sorry if the code below is badly formatted, but there's a clearer copy of the code at the bottom.

Python2.5 isn't in the Ubuntu 11.10 sources by default so in a console:

sudo add-apt-repository ppa:fkrull/deadsnakes
sudo apt-get update

and install python2.5 and some other stuff:
sudo apt-get install python2.5 python-virtualenv virtualenvwrapper python-pip

Next for project 'oinkyoinker':
export CURRENT=oinkyoinker
mkvirtualenv --no-site-packages --distribute --python python2.5 ${CURRENT}
workon ${CURRENT}
pip install fabric yolk ipython readline

Now download GAE and fix the path:
wget -O /tmp/
unzip /tmp/
echo "../../../google_appengine" > lib/python2.5/site-packages/gae.pth
and create a simple file server app:
mkdir -p application/static

echo """application: oinkyoinker
version: 1
runtime: python
api_version: 1
default_expiration: "7d"
- url: /
  static_dir: static
""" > application/app.yaml
and run it:
./google_appengine/ application/
Hope this helped you too.

MapReduce in Python

Over the last while I've been using NodeJS, MongoDB and Google's App Engine. Everything seems to have MapReduce functionality and frankly I was missing it when I went back to do some work in plain old Python. This is a nice short example of how it can be done.

The basic format that you need is something like this:

Now, a simple working example using the usual MapReduce example:

The output will look something like this: