Monthly Archives: February 2014

Setting up a Python 2.7.6 Virtual Env for Python development

Python is an excellent language to learn, for DBA’s who want to automate all the repetitive tasks, they need to perform. Once you start using python it is likely that you want to setup multiple environments with different versions of Python and libraries, based on the project you are working on. Virtualenv is a tool to create isolated python environments.

Below are the steps that i followed, to install a brand new working Python 2.7.6 environment with the following packages.

 
           SQLAlchemy    - Object Relational Mapper and SQL Toolkit for Python
           numpy         - Fundamental package for scientific computing
           matplotlib    - Python 2D plotting library
           ipython       - Interactive Python Shell
           pandas        - Python Data Analysis Library 
           Flask         - An easy to use Python Lightweight Micro Framework

This installation is performed on Ubuntu Linux, and i have already installed the libsqlite3-dev package and the oracle instant client.

Install Python 2.7.6

Download Python-2.7.6.tgz from http://www.python.org/getit

Install python 2.7.6 to your directory of choice.

		tar -xvf Python-2.7.6.tgz
		cd Python-2.7.6/

		./configure --prefix=/u01/Rk/Apps/Python/Python276
		make
		make install

Now you have python 2.7.6 installed into the /u01/Rk/Apps/Python/Python276 directory. (You will have a python binary in /u01/Rk/Apps/Python/Python276/bin)

Download virtualenv

curl -O https://pypi.python.org/packages/source/v/virtualenv/virtualenv-1.11.1.tar.gz

Install virtualenv

tar -xzvf virtualenv-1.11.1.tar.gz
cd virtualenv-1.11.1/
/u01/Rk/Apps/Python/Python276/bin/python virtualenv.py /u01/Rk/Apps/Python/p276env1

Activate the virtualenv

           . /u01/Rk/Apps/Python/p276env1/bin/activate

Install the additional Python Modules you need

	   pip install SQLAlchemy
	   pip install numpy
	   pip install matplotlib
	   pip install ipython
	   pip install pyzmq
	   pip install tornado
	   pip install jinja2
	   pip install pandas
	   pip install Flask
	   pip install Flask-SQLAlchemy

Install cx_Oracle

Ensure that the oracle instant client is installed, and the environment variables ORACLE_HOME and LD_LIBRARY_PATH are setup correctly.

Download cx_Oracle (a python extension module that allows access to oracle.) source from from http://cx-oracle.sourceforge.net/

tar -xzvf cx_Oracle-5.1.2.tar.gz
cd  cx_Oracle-5.1.2/
python setup.py install

Setup an alias (In your .bash_profile) to simplify invoking the virtualenv every time you want to use it.

alias p276env1='. /u01/Rk/Apps/Python/p276env1/bin/activate'

Now, anytime you want to execute a python program in this environment, you can invoke the Linux command line and

p276env1
python