Without Java, I wouldn’t be able to use JRuby.

And neither would I be able to use Warbler to create .war-files for drag and drop deployment.

In the span of 30 minutes (half of which is related to my underspec’d development environment), I was able to deploy a Rails application.

First, you need to setup your Rails application for use with JDBC. In Rails 2.0 it is as easy as this database.yml:

development:
host: localhost
adapter: jdbc
driver: com.mysql.jdbc.Driver
url: jdbc:mysql://localhost:3306/application_db
username:
password:

With the Warbler gem, you can easily create a war file:

jruby -S warble war

To fine-tune your configuration (if Warble’s defaults aren’t as good for you as they could), just run

jruby -S warble config

You can edit the resulting config\warble.rb for some fine tuning (I’ll have to look into it, for example how to tell it to use a specific JRuby version).

Once you are ready to create your .war-file:

jruby -S rake war:standalone:create

Thsi creates a war file inculding the JRuby runtime. Drop into your domain’s autodeploy folder, and wait until Glassfish is done deploying it. Done. You have a working, deployed, and automagically scaling Rails application. No need to herd a pack of Mongrels, futy with mod_proxy, or anything else. Wonderful.

BUT there is one issue you migth have (whcih is unrelated to Ruby, JRuby, or Glassfish):

It is possible that your Rails app throws the following exception:

No :secret given to the #protect_from_forgery call. Set that or use a session store capable of generating its own keys (Cookie Session Store).

Don’t fret. Either use the correct security, or change your app/controllers/application.rb so it looks like this:

protect_from_forgery :secret => ‘a_really_long_pseudo_random_hash_thing’

Simply remove the comment in front of the :secret. Done. Enjoy the bonus you just ensured for yourself, since you avoided at least a day of additional deployment and configuration, and/or learning capistrano.

P.S.: Still working on the comparison of OpenID and CAS for Ruby, so this is a bit of filler content.