Django district pip, virtualenv, virtualenv wrapper & more

Pip, Virtualenv, VirtualenvWrapper &

MoreDjango District

Wednesday, Nov. 7, 2012

Jackie Kazil@jackiekazil

Where we all start

● easy_install Globally● And it works! Yay!● But then....

○ dependencies or versions○ coordination w/ other developers○ keeping different systems on same page○ breaking sys python

Case study: Dependencies

Once upon a time in city, much like this one, there was a newspaper...

….. over 90 Django applications updated from 0.96 to 1.1.

Case study: Breaking sys python

From stackoverflow... "Is there a way to ensure I can clean everything up and start from zero?"

"If you remove everything in these 2 directories, it should clear out all modules...."

Why Pip & Virtualenv

● Isolate○ System packages from project packages○ Projects from each other

● No sudo required - sys python requires sudo access, project python doesn’t

Becoming the standard...

Pep 405Python 3.3

http://www.python.org/dev/peps/pep-0405

"... proposes to add to Python a mechanism for lightweight "virtual environments" with their own site directories, optionally isolated from system site directories...."

What is...

● pip - replaces easy_install

● virtualenv - creates isolated python environments

● virtualenvwrapper - to be explained later

Basic setup

$ sudo easy_install pip$ sudo pip install virtualenv$ sudo pip install virtualenvwrapper

Add to bash settings... source /usr/local/bin/virtualenvwrapper.shexport WORKON_HOME=$HOME/.virtualenvs

Make environment

$ mkvirtualenv foo

You can add more to this... like setting python version.$ mkvirtualenv --python=python2.7

What is virtualenvwrapper?

Helps make things easier...

workon foo vs

source ~/.virtualenvs/foo/bin/activate

Installing libraries

pip install djangopip install -r requirements.txtpip install -U django

Where does it live? ~/.virtualenv/foo/...

…/binBinaries in your env. Example: ipython

.../includeDev headers used by the #include directive in C.

…/libWhere all your python libraries will livelib/python2.7/site-packages

.../shareMans & Docs

Wrappers

● mkvirtualenv (calls hooks)● rmvirtualenv● workon (calls hooks)● add2virtualenv● cdsitepackages● cdvirtualenv● deactivate (calls hooks)

Hooks

● postmkvirtualenv● prermvirtualenv● postrmvirtualenv● postactivate● predeactivate● postdeactivate

Hook example: postactivate

proj_name=$(echo $VIRTUAL_ENV|awk -F'/' '{print $NF}')

if [ $proj_name = "foo" ]; then cd /opt/foo/core/ export DJANGO_SETTINGS_MODULE='settings.dev_settings' echo "DJANGO_SETTINGS_MODULE set to:" $DJANGO_SETTINGS_MODULEfi

Hooks example: postmkvirtualenv

https://gist.github.com/4034103

Other helpful stuff

pip freezepip freeze > requirements.txt

yolk -l

python -c "import sys,pprint;pprint.pprint(sys.path)"

More... virtualenv-burrito

https://github.com/brainsik/virtualenv-burrito

With one command.... BAM! (or maybe not)... a virtualenv & virtualenvwrapper environment

More... virtualenv-tools

https://github.com/fireteam/virtualenv-tools

"This repository contains scripts we're using at Fireteam for our deployment of Python code."

More... Tox http://tox.testrun.org/latest/

Tox as is a generic virtualenv management and test command line tool you can use for:● checking your package installs correctly with different

Python versions and interpreters

● running your tests in each of the environments, configuring your test tool of choice

● acting as a frontend to Continuous Integration servers, greatly reducing boilerplate and merging CI and shell-based testing.

More .... Keeping things fresh

Autoenvhttps://github.com/kennethreitz/autoenv"Magic per-project shell environments. Very pretentious."

Bundle Scouthttp://bundlescout.com/"Daily emails keep you on top of the latest updates from your favorite libraries."

More .... Keeping things fresh (cont)

Pip Linthttps://github.com/dcramer/piplint"Piplint validates your current environment with the requirements files you've specified."

Pip Toolshttps://github.com/nvie/pip-tools"A set of two command line tools to help you keep your pip-based packages fresh, even when you've pinned them"

The End

Me: Jackie Kazil, @jackiekazil

W/ contributions from... Chris Adams, @acdha

&Members of Django-District :-)http://www.django-district.org/