JRuby - How Java and Ruby meet on the JVM, PolyConf 2015

Slides from the talk at PolyConf
Poznan, Poland
July 2015

Transcript

1. JRuby How Java and Ruby meet on the JVM Alissa Bonas @ PolyConf 2015
2. What
3. • An implementation of the Ruby programming language atop the JVM • Written in Java What is JRuby
4. JRuby project • Free and open source software • http://jruby.org/ • https://github.com/jruby/jruby
5. Some JRuby facts • Exists since 2001 • Can run Ruby on Rails apps since 2006 • Tightly integrated with Java
6. Versions support • Jruby 1.7.x ◦ Supports Ruby 1.9.3 ◦ Experimental Ruby 2.0 support • Jruby 9.0.0.0 - in the works ◦ Supports Ruby 2.2
7. Why
8. Reasons to use JRuby • Integrate Java and Ruby projects • Enjoy libraries in both languages • Bonus ◦ Multithreading ◦ Packaging
9. Packaging • Simple deployment/packaging • Creating a standard war file
10. Multithreading • Green threads vs native threads ◦ GIL (global interpreter lock) • One process instead of multiple
11. Things to consider • Native C extensions • Slower startup
13. How
14. • RVM • Rbenv • Download and extract • Packaged for various OS Install JRuby
15. Install JRuby with RVM • Fast and easy • Quick switch between several Rubies
16. Managing Rubies with RVM
17. Ruby versions flavors
18. JRuby in action
19. Java Calling Ruby • Eval of Ruby code • Sharing variables with a Ruby script • Reading the return value
20. Java Calling Ruby • JRuby Embed (aka Red Bridge) ◦ Embed core ◦ JSR 223 - Java’s scripting engine ◦ BSF (Bean Scripting Framework) • No need to compile Ruby into bytecode
21. JRuby Embed core • Add jruby.jar to your Java project • specify JRUBY_HOME ◦ needed if JRuby installed via RVM
22. Ruby script example # GET http://10.35.0.23:8080/api require ‘net/http’ endpoint = URI::HTTP.build(:host => @host, :port => @port) endpoint.path = ‘/api’ request = Net::HTTP::Get.new(endpoint.to_s) resp = Net::HTTP.start(endpoint.host, endpoint.port) { | http | http.request(request) } resp.body
23. Java calling Ruby example
24. Output { "versions": [ "v1beta3", "v1" ] }
25. require ‘java’ java_import java.lang.System jruby_home = System.getProperties["jruby.home"] puts jruby_home ------------------------------------------------------------ Output: /home/abonas/.rvm/rubies/jruby-1.7.20 Ruby Calling Java
26. Example of Rails with JRuby • Open source Java project - Spago BI • Several Java reports engines • Adding a Ruby on Rails reports engine
27. Reports Engine 1 Reports Engine 2 Reports Engine 3 UI Reports Engine 4 http /engine1 http /engine2 http /engine3 http /engine4 SOA Tomcat SOA SOA SOA SOA
28. Preparation steps • Use JDBC database drivers • Package the application • Deploy
29. Database drivers • JDBC drivers • Specify them in Gemfile • Specify them in config/database.yml
30. Packaging
31. Packaging • Use Warbler • Create a .war file • Flexible configuration possibilities ◦ option to precompile the classes - avoid surprise in production
32. Rails production mode • Enabled by default in web.xml
33. Deploy and Enjoy!
34. Credits and sources • Tomcat-logo by The Apache Tomcat Project Team • Mug by Alex Getty from the Noun Project • Diamond by MarkieAnn Packer from the Noun Project • Box by Cornelius Danger from the Noun Project • Clapperboard by Edgar Vargas from the Noun Project • Questions by Rediffusion from the Noun Project • Rails by Luis Martins from the Noun Project