http://fr.droidcon.com/2014/agenda/detail?title=Scaling+Android+Development+at+Twitter In January 2012, nearly all Twitter for Android code was written by three engineers. As of January 2014, Twitter for Android has several dozens unique contributors from over ten different teams. In this talk, we'll discuss how Twitter moved to develop at scale from a single team-based development model to a project based development model that welcomes contributions from across the company and highlight some of the challenges that we ran into on the way. Speaker: Jan Chong, Twitter Jan Chong holds a BS and MS in Computer Science from Stanford University. She has Ph.D from the Management Science & Engineering Department, also from Stanford. She is currently the Engineering Manager for the Twitter for Android team. Prior to joining Twitter, Jan ran client and server software development at OnLive.

1. Scaling Android Development
Jan Chong @lessachu

2. 2011
Tardis c AntToeKnee Lacey

3. In Android...
Honeycomb c Karunakar Rayker

4. Twitter for Android
2011

5. twitter.com 2011

8. 2014 8463 c lozikiki

9. In Android...
Jelly Belly Jelly Beans c Anne

10. At Twitter...

11. Twitter for Android
2014

13. Cultural challenges

14. Web Brain

15. #ShipIt

16. #TestIt

17. Clients have long lives.

18. “Can’t we just upgrade all the
clients with this bugfix?”

19. Users decide when
to upgrade.

20. 80
70
60
50
Users
40
% 30
20
10
Days Since Release 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

21. Immature
development
environment

22. Mobile Brain

24. Android Brain

25. Experimentation

26. Unified Principles

27. Android Education

28. Buy a lot of phones.

29. Send developers to class.

30. #Simplify

31. +
twitter for android
application
twitter library
system library

32. Encourage participation.

33. Support Tooling

35. Experimentation
framework

36. Feature switches
stayathomeista.com

37. Contributor dashboard

38. Eat your own dogfood.

39. Crashlytics

40. #AutomateIt

41. Consistent
enforcement

42. Rapid Feedback

43. uiautomator

44. How we release

45. Monthly Releases

46. Release
Trains
Release Trains
The train(1) c Richard Taylor

47. Active Development
Active Development
Bug Fixing
Bake
WEEK 1
WEEK 2
WEEK 3
WEEK 4

48. Active Development Active Development Bug Fixing Bake

49. Make it cheaper to
take the next train.
Streetcar ticket, 1940 c Seattle Municipal Archives

50. Spread change over time.

51. WEEK N WEEK N + 1
Active Development
Critical Bugfixing/Bake
Two Week Staged Release

52. 1 WEEK N + 1 WEEK N - Active Development
Bugfixing/Bake Critical Bugfixing/Bake Critical Bugfixing/Bake
Critical Bugfixing/WEEK N
Development Active Development Active Development

53. WEEK N WEEK N + 1
Active Development
Critical Bugfixing/Bake
master
week n release branch

54. 1 WEEK N + 1 WEEK N week n - 1 release branch week n release branch week n + 1 release master
- Active Development
Bugfixing/Bake Critical Bugfixing/Bake Critical Bugfixing/Bake
Critical Bugfixing/WEEK N
Development Active Development Active Development

55. How do we find bugs faster?

56. Google Play Alpha Channel α

57. ββ Google Play Beta Channel

58. 1 WEEK N + 1 WEEK N week n - 1 release branch week n release branch week n + 1 release master
- Active Development
Bugfixing/Bake Critical Bugfixing/Bake Critical Bugfixing/Bake
Critical Bugfixing/WEEK N
Development Active Development Active Development
β β β
α α α

60. Questions?
@lessachu