This document discusses running Ruby on the Google App Engine (GAE) platform using JRuby. It notes that while GAE only supports Java and Python, JRuby allows Ruby code to run on the Java Virtual Machine, enabling deployment to GAE. It outlines some limitations of GAE like restrictions on file system access and lack of a relational database. Overall it presents JRuby and GAE as an option for running Ruby applications with the scalability benefits of GAE's infrastructure.

1. Placeholder for a Two-Line Title International Theme Ruby on Google App Engine Panagiotis Papadopoulos http://6pna.com - http://webz.gr 2nd Athens Ruby Meetup

2. From Ruby to JRuby We know Ruby MRI but Ruby runs on JVM too Like Ruby but runs on top of JVM JRuby is mature Ruby Thread are java threads GC is the bullet proof Java GC Java Unicode Compiled code GC and threading work seamlessly Huge variety of libaries deploy RoR with a single .war But ... gems need native extensions great performance needs JVM knowledge

3. Google App Engine What is App Engine exciting running on Google infrastructure limited & has unique methodologies Java & Python only scaling to infinity having an integrated enviroments almost free What is What is not Shared Hosting VPS a server to port my projects run commodity software (ex. phpBB) RDBMS a technology for noobs

4. Why do we need JRuby Because it can execute on App Engine JVM Learn the GAE limitations and tool set no relational database although GQL make it easier 1000 files upload limit not writable filesystem no custom TCP, UDP connection etc free up to 6.5 cpu hours index everything (or most) So what is good? no worries about scaling XMPP, Cron, Task Queue, Versions integrated environment free for most projects really cool

5. Where is Ruby and where is Rails? Not so straightforward a lot but tricky ORM through DataMapper memcache, actionmailer need patching console What works What does not work native extensions activerecord

6. How do we start? You are luckier now but wait for Rails 3 Appengine-Jruby for the rescue streamlines the process fetched jruby-rack, jruby, appengine-java-skd local server console deploy in a breeze Is that easy? not at all you need to package gems into jars (warble) jruby rack runs below rails/sinatra/merb Java exceptions restart server when testing :( Awesome admin environment, take a look

7. Integration, control, versioning, stats, tickets all in a blink. PanosJee “ ”

8. More reading Don 't miss http://delicious.com/panosjee/jruby lots of stuff I came across about jruby/gae http://code.google.com/p/appengine-jruby/ don 't start without it http://olabini.com/blog/ major contributor http://www.web2py.com/ if you are serious about GAE and want a real app http://www.sinatrarb.com/ ideal platform for Ruby on GAE http://bike-races.appspot.com/ the awesome demo

9. Thank you! Ruby Greece is maturing! http://6pna.com :: http://www.webz.gr