Ruby & JVM: A (JRuby) Love Story - RubyConfTh

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1. Ruby & JVM: A (Jruby) Love Story Yarden Laifenfeld @yardenlaif @yarden@hachyderm.io
2. 2 Who Am I? • Software Engineer at Rookout • Background in low level C programming in linux IOT environments • Ruby, Java, Go • C#, Python, JavaScript, C++
3. Non Breaking Breakpoints 3
4. What is JRuby? 4 “ JRuby is a 100% Java implementation of the Ruby programming language. It is Ruby for the JVM. ” - the JRuby wiki
5. Running an app 5 • rails server -p 8080 -e development
6. Running an app 6 rvm install jruby rvm use jruby bundle install
7. Running an app 7
8. Running an app 8 3 business days later…
9. Running an app 9 bundle config unset force_ruby_platform
10. Running an app 10 ➜ tutorial-ruby git:(master) ✗ jruby -S rails server -p 8080 -e development => Booting Puma => Rails 6.0.3.4 application starting in development => Run `rails server --help` for more startup options Puma starting in single mode... * Version 4.3.7 (jruby 9.2.9.0 - ruby 2.5.7), codename: Mysterious Traveller * Min threads: 5, max threads: 5 * Environment: development * Listening on tcp://[::1]:8080 * Listening on tcp://127.0.0.1:8080 Use Ctrl-C to stop
11. Running an app 11 ➜ tutorial-ruby git:(master) ✗ jruby -S rails server -p 8080 -e development => Booting Puma => Rails 6.0.3.4 application starting in development => Run `rails server --help` for more startup options Puma starting in single mode... * Version 4.3.7 (jruby 9.2.9.0 - ruby 2.5.7), codename: Mysterious Traveller * Min threads: 5, max threads: 5 * Environment: development * Listening on tcp://[::1]:8080 * Listening on tcp://127.0.0.1:8080 Use Ctrl-C to stop
12. Running an app 12 ➜ tutorial-ruby git:(master) ✗ jruby -S rails server -p 8080 -e development => Booting Puma => Rails 6.0.3.4 application starting in development => Run `rails server --help` for more startup options Puma starting in single mode... * Version 4.3.7 (jruby 9.2.9.0 - ruby 2.5.7), codename: Mysterious Traveller * Min threads: 5, max threads: 5 * Environment: development * Listening on tcp://[::1]:8080 * Listening on tcp://127.0.0.1:8080 Use Ctrl-C to stop
13. Supporting JRuby in one of Rookout’s debuggers 13
14. Decision Time 14 Java or Ruby
15. Java 15 • JVM API • Instrument bytecode • No debugger • Ruby API • Use built in functionality • Pry already exists Ruby
16. Decision Time 16 Java or Ruby
17. Supporting JRuby 17 ❏ Running an app ❏ Adding a breakpoint ❏ Collecting data
18. Running an app 18 • bundle add rookout • require 'rookout' ::Rookout.start
19. Running an app 19 ➜ tutorial-ruby git:(master) ✗ jruby -S rails server -p 8080 -e development
20. Running an app 20 ➜ tutorial-ruby git:(master) ✗ jruby -S rails server -p 8080 -e development [Rookout] Successfully connected to controller.
21. Running an app 21
22. TracePoints 22
23. TracePoints 23 tracepoint = Tracepoint.new(:line) do # Collect locals, stacktrace... end
24. TracePoints 24 t = TracePoint.new(:line) { |tp| p tp } t.enable(target: method(:m1))
25. TracePoints 25
26. TracePoints 26 trace_point = TracePoint.new :script_compiled do |tp| iseq = tp.instruction_sequence @iseqs << iseq end trace_point.enable
27. TracePoints 27 @iseqs.each do |iseq| if iseq.absolute_path == filename t = TracePoint.new :line do |tp| # Collect locals, stacktrace... end t.enable target: iseq, target_line: lineno end end
28. TracePoints 28
29. TracePoints in JRuby 29
30. Workaround 30 tracepoint.enable
31. Supporting JRuby 31 ✗ Running an app ❏ Adding a breakpoint ❏ Collecting data
32. Decision Time 32 Java or Ruby
33. Decision Time 33 Java or Ruby
34. Supporting JRuby 34 ❏ Running an app ❏ Adding a breakpoint ❏ Collecting data
35. Running an app - Java Agents 35 • -javaagent flag • premain entrypoint • Instrumentation API App JavaAgent Instrumentation API
36. Running an app 36 ➜ tutorial-ruby git:(master) ✗ jruby -J-javaagent:rook.jar -S rails server -p 8080 -e development
37. Running an app 37 ➜ tutorial-ruby git:(master) ✗ jruby -J-javaagent:rook.jar -S rails server -p 8080 -e development [Rookout] Successfully connected to controller.
38. Running an app 38 ➜ tutorial-ruby git:(master) ✗ jruby -J-javaagent:rook.jar -S rails server -p 8080 -e development [Rookout] Successfully connected to controller. => Booting Puma => Rails 6.0.6 application starting in development => Run `rails server --help` for more startup options Puma starting in single mode... * Version 4.3.12 (jruby 9.3.8.0 - ruby 2.6.8), codename: Mysterious Traveller * Min threads: 5, max threads: 5 * Environment: development * Listening on tcp://[::1]:8080 * Listening on tcp://127.0.0.1:8080 Use Ctrl-C to stop
39. Supporting JRuby 39 ✓ Running an app ❏ Adding a breakpoint ❏ Collecting data
40. Adding a breakpoint - Class Loaders 40 JVM Compiler Code Bytecode
41. Adding a breakpoint - Class Loaders 41 JVM 32 | … 33 | new Item() 34 | … Class Loader Get Item class bytecode Return Item class bytecode
42. Java Agent - ClassFileTransformer 42 JVM 32 | … 33 | new Item() 34 | … Class Loader Get Item class bytecode Return Item class bytecode Class File Transformer Return new Item class bytecode Item class bytecode
50. 50 A few, spaced out invocations Many, rapid invocations Class isn’t loaded Class is loaded
51. 51 A few, spaced out invocations Many, rapid invocations Class isn’t loaded Class is loaded JIT
52. JRuby Compilation Modes 52 • Interpretation • JIT • Compilation
53. JRuby Compilation Modes 53 compile.mode=FORCE
57. Supporting JRuby 57 ✓ Running an app ✓ Adding a breakpoint ❏ Collecting data
59. Collecting data 59
60. Collecting data 60
61. Supporting JRuby 61 ✓ Running an app ✓ Adding a breakpoint ✓ Collecting data
62. Things I Learned 62 • We can do awesome things • Smash your keyboard • Do meet your heroes
63. 63 Should you use JRuby?
64. JRuby Advantages 64 • Integration with Java libraries • Running atop the JVM ◦ Threads ◦ Long running applications
65. CRuby Advantages 65 • Larger community • More features
66. 66 Should you use JRuby? I don’t know, you choose.
67. Thank You! @yarden@hachyderm.io yardenlaif.com 67