1. Sunday, March 10, 13

2. From a monolithic
Ruby on Rails app
to the JVM
phil calçado
@pcalcado
http://philcalcado.com
JDC2013 - Cairo
Sunday, March 10, 13

3. 2011: Phil decides
to move to Berlin
Sunday, March 10, 13

4. Sunday, March 10, 13

5. Sunday, March 10, 13

6. Sunday, March 10, 13

7. Sunday, March 10, 13

8. Growing a product is awesome
Sunday, March 10, 13

9. http://bit.ly/building-the-next-soundcloud
Sunday, March 10, 13

10. Sunday, March 10, 13

11. Sunday, March 10, 13

12. > 10 hours of audio
uploaded every minute
~ 180 million users / month
Sunday, March 10, 13

13. But scaling is hard.
Sunday, March 10, 13

14. SoundCloud was
born on Rails
It allowed us to iterate real
fast and keep
code quality up(-ish).
Sunday, March 10, 13

15. Rails is simple.
Controller
ActiveRecord
Model
Database
Sunday, March 10, 13

16. Rails is simple.
Controller
ActiveRecord
Model
Database
If you want to write
a toy blog engine.
Sunday, March 10, 13

17. In the real world,
it gets messy.
Controller
ActiveRecord
Model
Database
Sunday, March 10, 13

18. In the real world,
it gets messy.
thin yajl
Controller amqp
EventMachine
haml
sc-caching ActiveRecord
DelayedJobs
Model
mysql master/
sc-logging slave adapter
Database Memcached
lhm nokogiri
statsy new relic
Real messy.
Sunday, March 10, 13

19. Scaling Rails is hard(er).
Sunday, March 10, 13

20. No concurrency?
1) Spawn A LOT of
processes.
Sunday, March 10, 13

21. No concurrency?
1) Spawn A LOT of
processes.
2) Make everything a
background job
Sunday, March 10, 13

22. No Virtual Machine?
Adapt your deployment
to > 1 minute application
bootstrap time
Sunday, March 10, 13

23. No proper Garbage
Collection?
Get used to restarting
processes. Frequently.
Sunday, March 10, 13

24. Scaling Rails
development is hard.
Sunday, March 10, 13

25. Idiomatic in Rails:
Sunday, March 10, 13

26. Idiomatic in Rails:
Just like Java circa 2004
Sunday, March 10, 13

27. Understanding the
Rails mindset:
http://bit.ly/not-a-virtue
Sunday, March 10, 13

28. Understanding the
Rails mindset:
i do not think it means
what you think it
means
http://bit.ly/not-a-virtue
Sunday, March 10, 13

29. If you are injecting
aggregation or composition
you are Doing it Wrong(tm)
Sunday, March 10, 13

30. Idiomatic in Rails:
Sunday, March 10, 13

31. Understanding the
Rails mindset:
http://bit.ly/trashable
Sunday, March 10, 13

32. Understanding the
Rails mindset:
Just like aop,
but even worse
http://bit.ly/trashable
Sunday, March 10, 13

33. Idiomatic in Rails:
Sunday, March 10, 13

34. Idiomatic in Rails:
no real complexity or
loC reduction
Sunday, March 10, 13

35. Rails is simple.
Controller
ActiveRecord
Model
Database
If you want to write
a toy blog engine.
Sunday, March 10, 13

36. Effectively, controllers
have a lot of logic
Controller
ActiveRecord
Model
Database
Sunday, March 10, 13

37. Effectively, controllers
have a lot of logic
Controller
ActiveRecord Model
Database
But so do models!
Sunday, March 10, 13

38. Where do we go
from here?
Sunday, March 10, 13

39. We will not do Java.
Sunday, March 10, 13

40. We, the Java community,
screwed up
Focused on the “Enterprise” while
nimbler companies took over
Sunday, March 10, 13

41. We, the Java community,
screwed up
Tried to solve core problems with
more complicated tooling
Sunday, March 10, 13

42. We, the Java community,
screwed up
JSF, Portlets, JavaFx, Oracle vs.
Android: the joke is on us
Sunday, March 10, 13

43. But we will do the JVM.
Sunday, March 10, 13

44. Who cares about Oracle/JCP?
So many modern languages.
None are “official”.
Sunday, March 10, 13

45. Who cares about Oracle/JCP?
It is crazy to use “Enterprise”
middleware at scale.
Sunday, March 10, 13

46. Who cares about Oracle/JCP?
twitter, Tumblr, Foursquare,
Netflix, Facebook, typesafe, etc.
are the new powerhouses.
Sunday, March 10, 13

47. Options:
1) Non-Rails Ruby
2) Scala
4) Clojure
Sunday, March 10, 13

48. Non-Rails Ruby
+ Simple
+ Easy to hire engineers
+ Lingua-franca inside SC
- Most code not thread-safe
- Lots of native code
- Rails mindset everywhere
Sunday, March 10, 13

49. Scala
+ “twitter stack” (Finagle, docs)
+ Good Java interop
+ Static typing
+ Good engineering practices
starting to emerge
- Binary compatibility
- Can get complicated
Sunday, March 10, 13

50. Clojure
+ Easier to get started with
+ Favours smaller apps
+ Good Java interop
- Very early days for engineering
good practices
- 3rd party libs a bit off in quality
Sunday, March 10, 13

51. Integrating Clojure with Jetty
Sunday, March 10, 13

52. Async I/O with Scala/Finagle
Sunday, March 10, 13

53. Let’s try them all.
Sunday, March 10, 13

54. Enabling
Sunday, March 10, 13

55. 1) Micro-services
- A couple of thousand LOC
- Once you grasp the domain, can
be rewritten in ~1 week
- Reduces risk in trying new things
Sunday, March 10, 13

56. internet
Legacy Application
(Rails)
Database
Sunday, March 10, 13

57. Sounds Users Stats Stream
Notifications Settings Recommender Messaging
Sunday, March 10, 13

58. Sounds Users Stats Stream
DB DB DB DB
Notifications Settings Recommender Messaging
DB DB DB DB
Sunday, March 10, 13

59. internet
API
Sounds Users Stats Stream
Notifications Settings Recommender Messaging
Sunday, March 10, 13

60. 2) Easy to deploy
- Old Rails system has fully
automated deployment
- From change to production
should take minutes
- Integrated to CI
- Reverting is easy
Sunday, March 10, 13

61. Sunday, March 10, 13

62. Sunday, March 10, 13

63. Sunday, March 10, 13

64. Sunday, March 10, 13

65. Current status
- ~6 new or extracted systems
- 3 Clojure
- 1 Scala
- 2 JRuby
Sunday, March 10, 13

66. Current status
Rule of thumb:
1 JVM = 10 thins
Sunday, March 10, 13

67. main takeaways
Sunday, March 10, 13

68. Rails, PHP, etc. are a very good
choice to start something
Sunday, March 10, 13

69. You need to know when
to migrate away
Sunday, March 10, 13

70. Build infrastructure to reduce
the risk of trying new things
Sunday, March 10, 13

71. The JVM is still the best
multi-language VM out there
Sunday, March 10, 13

72. There is a lot of
JVM-related stuff
happening outside
the official channels
Sunday, March 10, 13

73. Even if you are doing Java,
drop the extra weight
Sunday, March 10, 13

74. Java is the new C
Sunday, March 10, 13

75. phil calçado
http://philcalcado.com
@pcalcado
www.soundcloud.com
Sunday, March 10, 13