Manage python environment with virtualenv

Introduction

Python has a module called virtualenv that makes it easy to create a virtual environment. If you want to install some module as a trial, you can create an environment with virutalenv, install it there, and try it, and the system environment can be used intact. Since you can create multiple environments, it is convenient to divide by python version. If you don't like it, just erase or use the environment.

Note that it is convenient to install virtualenv and virtualenvwrapper, which can easily manage it, as a set.

• ubuntu14.04
• Mac OSX Yosemite（10.10.3）

install and setup

ubuntu

#Install without pip
$ sudo apt-get install python-pip
#If you use python, you may get an error due to the dependency, so install this as well
$ sudo apt-get install python2.7-dev

# virtualenv /Install virtualenvwrapper
$ sudo pip install virtualenv
$ sudo pip install virtualenvwrapper

mac

Mac should be able to use pip from the beginning.

# virtualenv /Install virtualenvwrapper
$ sudo pip install virtualenv
$ sudo pip install virtualenvwrapper

setup

To use virtualenvwrapper, you need to add the following script to bashrc.

$ vim ~/.basrhc  #mac is`~/.bash_profile`
    source /usr/local/bin/virtualenvwrapper.sh
    export WORKON_HOME=~/.virtualenvs

Try using

Create

There are various options, but I want to use it in a clean state of the system, so basically I only add --nosite-package.

# mkvirtualenv <option> <Environment name>
$ mkvirtualenv --no-site-package hoge
    # --never-download        :Do not DL from the network
    # --system-site-packages  :Use installed modules
    # --no-site-packages      :A virtual environment is created with all installed modules removed

#When created, the environment name will be added to the leftmost at the command prompt
(hoge)$

Check the created environment directory

--Move to environment directory

(hoge)$ cdvirtualenv
#Check the directory
(hoge)$ pwd
    /home/hoge/.virtualenvs/hoge
#Contents is like this
(hoge)$ ls
    bin  include  lib  local

Try installing the module

--Back up with git and try installing other modules

#Commit the entire environment to local git
(hoge)$ git init; git add -A; git commit -a -m "init"
#Something useful`Twisted`Try installing the module
(hoge)$ pip install twisted

--If you look at the difference with git, various new additions have been made.

(hoge)$ git status
     On branch master
    # Untracked files:
    #   (use "git add <file>..." to include in what will be committed)
    #
    #	bin/cftp
    #	bin/ckeygen
    #	bin/conch
    #	bin/lore
    #	bin/mailmail
    #	bin/manhole
    #	bin/pyhtmlizer
    #	bin/tap2deb
    #	bin/tap2rpm
    #	bin/tapconvert
    #	bin/tkconch
    #	bin/trial
    #	bin/twistd
    #	lib/python2.7/site-packages/Twisted-15.1.0-py2.7.egg-info/
    #	lib/python2.7/site-packages/twisted/
    #	lib/python2.7/site-packages/zope.interface-4.1.2-py2.7-nspkg.pth
    #	lib/python2.7/site-packages/zope.interface-4.1.2-py2.7.egg-info/
    #	lib/python2.7/site-packages/zope/
    #	pip-selfcheck.json
    #

--Try using the installed module immediately

#Can be imported
(hoge)$ python -c "import twisted"

--Try using it away from the environment

#Environmental outage
(hoge)$ deactivate
#I get an error when I try to use it on the original system
$ python -c "import twisted"
    Traceback (most recent call last):
      File "<string>", line 1, in <module>
    ImportError: No module named twisted

This shows that it is not installed in the system environment.

List of frequently used commands

deactivate: Deactivate the environment

#Environmental outage
(hoge)$ deactivate
$

workon: Move to environment

If you already have an environment, you can move to that environment with the workon command.

$ workon hoge
(hoge) $

lssitepackages: List of installed packages

(hoge)$ lssitepackages
    Twisted-15.1.0-py2.7.egg-info  pip-6.1.1.dist-info        zope
    _markerlib                     pkg_resources              zope.interface-4.1.2-py2.7-nspkg.pth
    easy_install.py                setuptools                 zope.interface-4.1.2-py2.7.egg-info
    easy_install.pyc               setuptools-15.0.dist-info
    pip                            twisted

rmvirtualenv: Erase the environment

You can delete the entire folder, but of course there is also a command to delete the environment.

$ rmvirtualenv hoge

The end

You can use this, even if you try various things, you can clean it up by deleting the entire environment. It's a perfect environment for me as a clumsy person (; ^ _ ^