Evolve

FreshBooks is a PHP shop then?

Legacy

Rewrite?

Dog Food

Evolve

• Test Drive
• Mitigate Risk
• Unit Test
• Go Slow
• Release Often
• Follow Through

RESTful

Service Oriented

Data Access

http://java.sun.com/blueprints/corej2eepatterns/Patterns/DataAccessObject.html

Serialization

Deploying

Memory

Performance

• Focused on Correctness
• Extended Query
• Second Level Cache

• AltertSite
• Latency Curl
• Repoze AccumulatingProfileMiddleware
• cProfile

Unit Testing

Decorators

Community

Questions?

Developer Blog:

I’ve got a little secret to share about our technology stack here at FreshBooks. Although by all appearances we are just another PHP shop, FreshBooks has actually been powered by Ruby on Rails for about three years now. Here’s how we did it:

routes.rb:

...

I blame this guy

anonymous comment in response...

[diana@devimage ~]$ source mydevenv/bin/activate

(mydevenv)[diana@devimage ~]$ cd workspace/evolve

(mydevenv)[diana@devimage evolve]$ python setup.py develop

FreshBooks is a rails shop, right?

developers.

freshbooks.com/

api/webhooks/

requests/sec, fast enough, metrics

What?

• Database
• Back-end
• Front-end

How?

php + python

Language

(mydevenv)[diana@devimage evolve]$ paster serve --reload development.ini

serving on 0.0.0.0:5000 view at http://127.0.0.1:5000

http://pylonshq.com/docs/en/1.0/gettingstarted/#installing

The Hard Part

What would it take to transform our code base into something we were actually proud of?

Understanding the Python GIL

Why *not* PHP?

• Founded in 2003
• Filled a Void
• Got it to Market

• Developer Satisfaction
• Not the Legacy Language
• Community & Tools
• Gulf of Expectation

http://us.pycon.org/2010/conference/schedule/event/76/

• Old-style vs. New-style classes
• Dynamical Mappings
• Brute Force Sharding
• Python Weakref Dict Bugs
• Garbage Collection

Automatic Type Conversion

(mydevenv)[diana@devimage evolve]$ python setup.py sdist bdist_egg

evolve-2.29-py2.6.egg

]evolve-2.29.tar.gz

Truth(iness)

ORM

LegacyDatabase

Oh, the hilarity ...

It's Complicated.

• Hibernate Like
• SQL Expression Language
• Defined Relationships
• Lazy/Eager Loading
• Insane Sharding

Legacy Code

• MyISAM
• No Transactions
• No Foreign Keys
• Insane sharding
• Back-Ups
• Priming the Cache

• Tangled PHP + HTML + SQL
• Tons of One-Off Queries
• Code Duplication
• Huge Blocks
• Global Scope Abuse

ORM Spike

• Zend_db, Propel, Doctrine, Django ORM
• SQLAlchemy (complete, sharding)
• Django Web Framework + Django ORM
• Pylons

'cause every tool is a

weapon

if you hold it

right

A Poor Carpenter Blames His Tools

whatever...

Connect

folder.child_folders() folder.parent_folder()

Generated Code

coverage

(mydevenv)[diana@devimage evolve]$ nosetests --exclude=integration

AMQP Messaging

nose

Give Back

http://developers.freshbooks.com/blog/

$$ Cash Money $$

Commits to SQLAlchemy

def test_<method_under_test>___<edge_case1>___<edge_caseN>

Grow

#sqlalchemy

groups.google.com/group/sqlalchemy

#pylons

groups.google.ca/group/pylons-discuss

Cloud

RailsConf 09: Robert Martin, "What Killed Smalltalk Could Kill Ruby, Too"

http://blip.tv/file/2089545

base_dao

testing is hard --

like proofs are hard