Debian (development tips)

Jpeg support in PIL and pillow.

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$ sudo apt-get install libjpeg libjpeg-dev libfreetype6 libfreetype6-dev zlib1g-dev
$ sudo ln -s /usr/lib/`uname -i`-linux-gnu/libfreetype.so /usr/lib/
$ sudo ln -s /usr/lib/`uname -i`-linux-gnu/libjpeg.so /usr/lib/
$ sudo ln -s /usr/lib/`uname -i`-linux-gnu/libz.so /usr/lib/

Installing lxml in Python (Debian based).

If you're getting the "fatal error: libxml/xmlversion.h: No such file or directory" error, just install the following development files:

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$ sudo apt-get install python-dev libxml2-dev libxslt1-dev

Problems with 'matplotlib' and freetype.

If you're having problems installing matplotlib in a Python virtualenv, and are getting the 'freetype missing' error, you sould install the development files for freetype, and (in most cases) rebuild the python dependencies for matplotlib.

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$ sudo apt-get  -u install libfreetype6-dev
$ sudo apt-get build-dep python-matplotlib

After that, you can just use pip normally to install matplotlib

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$ pip install matplotlib

PS. I know of cases where you have to update python-virtualenv and python-pip after you use build-dep. Just apt-get upgrade your installation. Today I learned about the 'pydoc' command from Python.

Problems with locale

In some machines I've found problems when setting locales from Python. First check the results of running

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$ locale

In my case is:

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LANG=es_VE.UTF-8
LANGUAGE=es_VE:es
LC_CTYPE="es_VE.UTF-8"
LC_NUMERIC="es_VE.UTF-8"
LC_TIME="es_VE.UTF-8"
LC_COLLATE="es_VE.UTF-8"
LC_MONETARY="es_VE.UTF-8"
LC_MESSAGES="es_VE.UTF-8"
LC_PAPER="es_VE.UTF-8"
LC_NAME="es_VE.UTF-8"
LC_ADDRESS="es_VE.UTF-8"
LC_TELEPHONE="es_VE.UTF-8"
LC_MEASUREMENT="es_VE.UTF-8"
LC_IDENTIFICATION="es_VE.UTF-8"
LC_ALL=

Then use:

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import locale

try:
    locale.setlocale(locale.LC_ALL, 'es_VE.utf-8')
except locale.Error:
    raise

Change es_VE.UTF-8 for yours.

Creating postgresql roles

This one is not just for Debian based systems, but for PostgreSQL, giving privileges to a specific user in your Database Server is really simple:

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CREATE USER user_name WITH PASSWORD 'userpasswd';

CREATE DATABASE new_database;

GRANT ALL PRIVILEGES ON DATABASE new_database to user_name;

Local dependencies for scipy

Before you're able to build scipy using pip install, you'll need to have some dependencies installed.

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$ sudo apt-get -u install libatlas-base-dev libatlas-dev liblapack-dev libblas-dev

You'll also need a Fortran compiler installed.

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$ sudo apt-get -u install gfortran