clean all the things: encouraging clean code in big teams

ZILLOW | TRULIA | STREETEASY | HOTPADS

CLEAN ALL THE THINGS!ENCOURAGING CLEAN CODE IN BIG TEAMS

Dave Rochwerger, Engineering Director, Agent Platform @catchdave



Zillow Group

• Culture is paramount

• Many teams, many offices (SF office > 200 engineers)

• Up to 100 engineers contribute to a repository

• Many products, release cycles & techs

Clean Code


Clean Code

• Low defects

• Maintainable

• Testable

Clean code in large companies?


2014: The Bad

• Too many bugs

• Highly coupled, low communication teams

• Preventable mistakes (code quality & releasing)

• Inconsistent testing knowledge & usage


2014: The Good

• Company-wide training

• Code quality guidelines

• IDE plugins

• Git hooks

• Post-merge CI jobs


Mr. CleanEncouraging high code quality


Mr. Clean Goals1. Push defect detection as early as possible

2. Make it difficult to contribute bad code

3. Make it easy to contribute good code

• Automate away easy things

• Code review focus should be subjective

Design' Coding' QA' Post/release'

Effort'


“Culture eats strategy for breakfast”


Blocks Merging


Stash Integration


Jenkins Integration


Approach• Lots of testing

• Kept goals in sight

• Iterate, iterate, iterate

• Garner constant feedback

• Stealth deployment (nothing like testing in prod)

• Communicate, communicate, communicate


Results (so far)

• 15,000 PRs examined since May

• Bugs were found on day 1

• Test suites 100% usable

• Many “saved my life” anecdotes


Results (so far)

Bugs per week down 30%

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Bugs%fo

und%

Week%Number,%2015%

Team%A%Bugs%

Team"A" Expon."(Team"A)"

Mr."Clean""

The Future


Insights Reporting


Take-aways

• Clean code is important

• Clean code is harder in large teams

• Fostering the right culture is key

• Spread the word about your great work!


Questions?

Dave Rochwerger @catchdave


clean all the things: encouraging clean code in big teams

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