Migrate to JRuby

My Talk on Ruby Conf China 2013, experience about how we migrate Ruby on Rails project to JRuby in Groupon Payments.

1. Migrate to JRuby What We Learned
2. ian yang @doitian
3. Agenda • Background • How to Migrate • What We Learned
4. Background
5. Breadcrumb Payments
6. The Codebase • 4 Ruby on Rails applications • Ruby 1.9.2 and Rails 3.2.1
7. Why JRuby? • Multithreading • Memory Leak • Easy integration of libraries on JVM
8. How to Migrate
9. Choose a Deploy Strategy
10. Warbler Trinidad TorqueBox Archive File ✔ ✔ ✔ Capistrano ✔ ✔ Scheduler ✔ ✔ Background Jobs ✔ ✔ Clustering ✔
11. Warbler Trinidad TorqueBox Archive File ✔ ✔ ✔ Capistrano ✔ ✔ Scheduler ✔ ✔ Background Jobs ✔ ✔ Clustering ✔
12. JRuby-Lint https://github.com/jruby/jruby-lint
13. What We Learned
14. Gems Alternatives
15. Wiki: C Extension Alternatives https://github.com/jruby/jruby/wiki/C-Extension- Alternatives
16. Lock Compatible Version
17. gem 'rubyzip', '<1.0.0'
18. *nix to JVM
19. • No Kernel#fork • Cannot trap all signals
20. Kernel#fork → Thread.new
21. Thread-safety
22. Avoid Sharing Mutable State Between Threads
23. Global Variable ⾠ Class Variable ⾠ Class Instance Variable ⾠
24. Lazy Initialization → Preload
25. class Cvv def self.redis @@redis ||= Redis.new(...) end end ✘
26. class Cvv def self.redis @@redis end def self.redis=(r) @@redis = r end end ! # config/initializers/cvv.rb Cvv.redis = Redis.new(...) ✔
27. Thread Local Storage
28. class Processor class_attribute :skip ! def execute do_something unless self.class.skip end end ✘
29. class Processor def self.skip Thread.current['Processor.skip'] end def self.skip=(s) Thread.current['Processor.skip'] = s end end ✔
30. Atomic Variable
31. class Airlock class_variable :enabled end ✘
32. # gem 'atomic'! class Airlock! @@enabled = Atomic.new(false)! def self.enabled! @@enabled.value! end! def self.enabled=(e)! @@enabled.update { e }! end! end ✔
33. Locks require 'thread'! mutex = Mutex.new! ! Thread.new do! mutex.synchronize do! ...! end! end
34. Reference: Concurrency in JRuby https://github.com/jruby/jruby/wiki/Concurrency-in- jruby
35. Reference: Ruby Mutithreading http://www.tutorialspoint.com/ruby/ ruby_multithreading.htm
36. Resque
37. • No Fork • Jobs run in the same process • Free the resources
38. OpenSSL
39. Full OpenSSL Support gem 'jruby-openssl'
40. Different Cryptography Implementations https://github.com/jruby/jruby/issues/931
42. Cryptography Adapter • Use OpenSSL in CRuby • Use JCE directly in JRuby (java_import)
43. Tuning
44. TorqueBox + JBoss
45. Connection Pool Size
46. Thread Pool Size
47. JVM Memory
48. How To? • Benchmark • Monitoring
49. References
50. Deploying with JRuby
51. JRuby Wiki https://github.com/jruby/jruby/wiki