Bootstrapping Django with ease OSCON 2012 www.concentricsky.com @concentricsky // biglan / wiggins / bothun Thursday, July 19, 12
Introductions Mike Biglan Wiggins Josh Bothun CTO Architect Senior Developer @co ffi ndragger Thursday, July 19, 12
Areas of Concentric Sky Web/Django Mobile Enterprise Thursday, July 19, 12
(Some) Technologies We Use • Chef • Backbone.js • Jenkins • Jinja2 • AWS • Celery • Sphinx • DebugToolbar • Memcached • jQuery / jQueryUI • South • Compass / Sass • git • Mongo & MySQL Thursday, July 19, 12
Released CSky Creations • djenesis – Easy Django Bootstrapping • breakdown - Lightweight jinja2 template prototyping server • django-cachemodel – Automatic caching for django models Thursday, July 19, 12
CSky Creations in the Works • skycloud – Tool for AWS auto-scaling • django-skycms – CMS as a library • django-sky-visitor – Invitations, email con fi rmation, etc • django-client-admin – Flexible admin for client Thursday, July 19, 12
CSky Teams 10 Django Team 5 Design Team STAFF 50+ 9 PM Team 3 System Admins Thursday, July 19, 12
Team Interfacing • Each project is a mix from each team • Members might switch amongst projects • Interfaces between teams • Clean separation of hando ff s and responsibilities • Best-practices shared within teams Thursday, July 19, 12
“Bootstrapping” • Pulling one up by one’s bootstraps • Computers do this much better than humans • Django – starting a project, new or existing Thursday, July 19, 12
Bootstrapping with Ease Making booting (and rebooting) a django project as easy as possible • Ease is a continually moving target • Shouldn’t sacri fi ce other goals for ease (e.g. security, modularity, be PHP) Thursday, July 19, 12
Moving Targets Moving targets create new problems. And new solutions. • CGI – Solving static HTML • JavaScript – Solving non-interactivity • CSS – Solving 100+ HTML pages • Puppet/Chef – Solving 100+ servers Thursday, July 19, 12
Problem/Solution Lifecycle 1. Problem grows 2. Many create their own solution ; some polish; some release 3. Community fl ocks to one (or a few) solutions 4. Solution(s) gets anointed and others die o ff Thursday, July 19, 12
Goals of Easy Bootstrapping 1. More people using Django 2. More people using Django better Thursday, July 19, 12
More People Using Django • As few commands as possible to try Django out • And to try someone else’s project out. • Must be highly likely to just work • All especially critical for beginners • Django’s runserver & sqlite...great! • It just works... Thursday, July 19, 12
Making Mistakes should be Hard • Checklists are great • The best checklists are invisible • To automate lists of commands, must have consistency Thursday, July 19, 12
Consistency Makes things Easier • Ease of replication across servers • Ease of sharing • Both templates and existing projects • Easier to build upon Thursday, July 19, 12
Consistently Standardized • Standardization: a tool to get to consistency • This can be in an organization. Or the full community • Oh yeah, and... Thursday, July 19, 12
Standard had Better be Right Thursday, July 19, 12
Fragmentation • Poor standards lead to fragmentation • Hard to build things on top of fragmented environments • Imagine building for single browser. Not Mosaic. Thursday, July 19, 12
Android Fragmentation http://www.businessinsider.com/android-fragmentation-chart-from-opensignalmaps-2012-5 Thursday, July 19, 12
Flexibility vs Standardization • Standardization can be rigid; can kill fl exibility • Especially as the target moves • E.g. contrib.auth • Flexibility allows preference, innovation • Best of both worlds is standardization with structured options of fl exibility • Django does this well Thursday, July 19, 12
Django • Django is a set of higher-order building blocks • If blocks are too large , sacri fi ces what can be made (i.e. not fl exibile) • If blocks are too small , becomes ine ffi cient and unmanageable • If block types are wrong , not loosely coupled (i.e. non-orthogonal) Thursday, July 19, 12
3 Stages of Project Structure Grief • Denial • Bargaining • Acceptance Thursday, July 19, 12
Denial I’ll just take the easy way out... • Stu ff required libraries in a ‘lib’ directory • Stick django there too • Name everything MyProjectSomething Thursday, July 19, 12
Denial I’ll just take the easy way out... Why this doesn’t work • project starts to get bloated • version management becomes a headache • upgrade paths become tangled Thursday, July 19, 12
Bargaining We’ll just adopt some standard practices... 1. Have the team argue about which way to do things 2. Assign someone to write a document about it 3. ??? 4. Ignore it when you start a new project Thursday, July 19, 12
Bargaining We’ll just adopt some standard practices... Why this doesn’t work • Projects become inconsistent • It is not in source control • No way to manage changes across projects • There is no history of changes or discussion Thursday, July 19, 12
Acceptance Embrace the community • requirements.txt, version management • also solves the ‘git submodule’ problem • virtualenv is great, always use it Thursday, July 19, 12
Acceptance No, really, use virtualenv • dependency management • concurrent project management • sand-boxing • solves the “chicken-n-egg” problem • replication Thursday, July 19, 12
What’s in a template? • For a django project, there are two styles: 1. toplevel directory is python code 2. toplevel directory is a website project Thursday, July 19, 12
Toplevel is python code • Pros ./manage.py ./my_project/__init__.py • More pythonic; Everything ./my_project/settings.py ./my_project/urls.py is python code ./my_project/wsgi.py • It just works Django’s default template • Cons • Everything is python code • Where do non public fi les go? Thursday, July 19, 12
Default Django Project • Where do apps go? ./manage.py ./my_project/__init__.py ./my_project/settings.py • How about ./my_project/ ./my_project/urls.py ./my_project/wsgi.py my_app/? ./my_project/my_app/__init__.py ./my_project/my_app/models.py • Name then becomes ‘my_project.my_app’ • What about reusability? • What if I want to rename my_project? Thursday, July 19, 12
Default Django Project • Where do apps go? ./manage.py ./my_project/__init__.py ./my_project/settings.py • How about ./my_app/? ./my_project/urls.py ./my_project/wsgi.py • Better for reusability, but... ./my_app/__init__.py ./my_app/models.py • Now I have to add ./ to the PYTHON_PATH Thursday, July 19, 12
Default Django Project • What was the name ./manage.py ./myapp1/models.py ./myapp1/urls.py again? ./myapp2/models.py • Was it ‘myapp1’ or ‘myapp2’ ./myapp2/urls.py ./myapp3/models.py that contains the main urls ./myapp3/urls.py and settings... Thursday, July 19, 12
Toplevel is website project • Pros ./manage.py ./wsgi.py ./requirements.txt • Closer to real world ./apps/mainsite/__init__.py ./apps/mainsite/settings.py ./apps/mainsite/settings_local.py environments ./apps/mainsite/urls.py ./apps/my_app/models.py • Consistency across ./apps/my_app/urls.py projects • Cons • ??? None I guess! http://github.com/concentricsky/djenesis-template.git Thursday, July 19, 12
Toplevel is website project ./manage.py ./wsgi.py ./requirements.txt ./apps/mainsite/__init__.py ./apps/mainsite/settings.py ./apps/mainsite/settings_local.py.example ./apps/mainsite/urls.py ./apps/my_app/models.py ./apps/my_app/urls.py Python code is sandboxed • only have to add ./apps to PYTHON_PATH • everything else is ignored by WSGI server Thursday, July 19, 12
Toplevel is website project ./manage.py ./wsgi.py ./requirements.txt ./apps/mainsite/__init__.py ./apps/mainsite/settings.py ./apps/mainsite/settings_local.py.example ./apps/mainsite/urls.py ./apps/my_app/models.py ./apps/my_app/urls.py Consistent Entry Point Name • I always know where to look fi rst: ./apps/ mainsite/urls.py • More important than it may seem at fi rst blush Thursday, July 19, 12
Toplevel is website project ./manage.py ./wsgi.py ./requirements.txt ./apps/mainsite/__init__.py ./apps/mainsite/settings.py ./apps/mainsite/settings_local.py.example ./apps/mainsite/urls.py ./apps/my_app/models.py ./apps/my_app/urls.py settings_local • Loaded after settings.py as overrides. • Easily set up a local development environment. • Production credentials are at no risk. • Easily deploy devel, staging, production stacks. Thursday, July 19, 12
Toplevel is website project ./manage.py ./wsgi.py ./requirements.txt ./apps/mainsite/__init__.py ./apps/mainsite/settings.py ./apps/mainsite/settings_local.py.example ./apps/mainsite/urls.py ./apps/my_app/models.py ./apps/my_app/urls.py I have requirements.txt • Library dependencies and versioning is simple. • New developers can start working quicker. • Simple virtualenv integration Thursday, July 19, 12
Okay, but now what? 1. Install and use virtualenv 2. Design and use a template Thursday, July 19, 12
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