simon stewart, facebook engineer - building facebook for android

Simon Stewartsimons@fb.com

github.com/shs96c@shs96c

Move Fast and Build Things

The Challenge

>300 engineers

>150,000 files

>100,000 commits

There is no Android team

How do we “move fast”?

Build fast

The working copy

▪We use git for source control

▪Two branches we care about day-to-day:

▪ master

▪ stable

How the code is organized

Text

http://www.flickr.com/photos/darwinbell/3030214710/

Code review

Image macros

QuickTime™ and aGIF decompressor

are needed to see this picture.

Dependency injection

http://www.flickr.com/photos/31246066@N04/5253179784/

We needed a better tool

▪Minimal overhead in creating a module

▪Keep boilerplate out of the codebase

▪ IDE friendly

▪Faster clean builds

▪Faster incremental builds

▪Support ad-hoc build steps

Buck: an Android build system

▪build rule procedure for producing output files from input files

▪build file file (named BUCK) where build rules are declared

▪build target string identifier for a build rule

Build Target

//java/com/facebook/share:ui

Root of the repository

Directory where the build file can be found

Name of the build rule

Build Rule

android_library( name = 'ui', srcs = glob(['**/*.java']), deps = [ '//android_res/com/facebook/share:res', '//java/com/facebook/base:base', '//third-party/java/guava:guava', ], visibility = [ 'PUBLIC' ],)

Dependency Graph

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Dependency Graph

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Buck is Open Source!

▪Available on GitHub: https://github.com/facebook/buck/

▪Documentation galore: http://facebook.github.com/buck/

▪Apache 2.0 License

▪Written in Java and a smattering of Python

▪Works on OS X and Linux

Test fast

Developers write tests

Unit tests

http://www.flickr.com/photos/aracelota/4773084433/

Larger tests

http://www.flickr.com/photos/amphalon/6510474165/

Deploy fast

Dogfood, Alpha and Beta

Questions?