Shahzad Bhatti Welcome to my ramblings and rants!

In my last blog, I wrote about recent JRuby on Rails project I did at amazon. In this blog, I will show some technical details on setting up JRuby on Rails with Tomcat. I used 2.1.1 of Rails and 1.1.4 of JRuby, here are steps to setup JRuby and Rails:

• Download Jruby 1.1.4 from http://dist.codehaus.org/jruby/
• Setup JRUBY_HOME and PATH

   export JRUBY_HOME=installed directory of jruby
   export PATH=$JRUBY_HOME/bin:$PATH
   

• Install Rails

   gem install rails -y
   

• Install ActiveRecord JDBC Adapter

   jruby -S gem install activerecord-jdbc-adapter
   

• Install warbler plugin to create war file, older version of Rails (1.2 or older) used goldspike but the newer version requires warbler

   jruby -S gem install -y  warbler
   

• Edit config/environment.rb and add

   if RUBY_PLATFORM =~ /java/
     require 'rubygems'
     RAILS_CONNECTION_ADAPTERS = %w(jdbc)
   end
   

• Download mysql-jdbc driver as I used MySQL. (You may have to download different driver. )
• Copy mysql-connector-java-5.1.6-bin.jar to lib directory of jruby
• You can edit config/warble.rb and add other jar files or directories, e.g.

     config.java_libs += FileList["lib/*.jar"]
     config.pathmaps.java_classes << "%{build/classes/,}p"
     config.webxml.jruby.min.runtimes = 2
     config.webxml.jruby.max.runtimes = 24
   

• Edit config/environment.rb and add define adapter, driver and url as follows:

   development:
     adapter: jdbc
     driver: com.mysql.jdbc.Driver
     url: jdbc:mysql://localhost/rspm_development
     username: rspmdb_user
     password: secret
                                                                                                                                                         
   test:
     adapter: jdbc
     driver: com.mysql.jdbc.Driver
     url: jdbc:mysql://localhost/rspm_test
     username: rspmdb_user
     password: secret
                                                                                                                                                         
   production:
     adapter: jdbc
     driver: com.mysql.jdbc.Driver
     url: jdbc:mysql://localhost/rspm_production
     username: rspmdb_user
     password: secret
   

• Create a template web.xml.erb in config directory, e.g.

   <!DOCTYPE web-app PUBLIC
     "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
   
     "http://java.sun.com/dtd/web-app_2_3.dtd">
   <web-app>
                                                                                                                                                         
       <% webxml.context_params.each do |k,v| %>
       <context-param>
           <param-name><%= k %></param-name>
           <param-value><%= v %></param-value>
   
       </context-param>
       <% end %>
                                                                                                                                                         
      <servlet>
         <servlet-name>Rails</servlet-name>
         <servlet-class>org.jruby.rack.RackServlet</servlet-class>
   
      </servlet>
                                                                                                                                                         
      <servlet-mapping>
          <servlet-name>Rails</servlet-name>
          <url-pattern>/*</url-pattern>
      </servlet-mapping>
   
                                                                                                                                                         
                                                                                                                                                         
     <filter>
       <filter-name>RackFilter</filter-name>
       <filter-class>org.jruby.rack.RackFilter</filter-class>
     </filter>
   
     <filter-mapping>
       <filter-name>RackFilter</filter-name>
       <url-pattern>/*</url-pattern>
     </filter-mapping>
                                                                                                                                                         
      <listener>
   
         <listener-class><%= webxml.servlet_context_listener || 'org.jruby.rack.RackServletContextListener'%></listener-class>
      </listener>
                                                                                                                                                         
   </web-app>
                                                                                                                                                         
   

• Now create war file

   jruby -S warble
   

• Finally copy the war file to webapps directory of standard J2EE web container, in my case Tomcat 6.0
• Now point the browser to your server, e.g. http://localhost:8080/your-controller and voilla.

On final note, I found warble quite slow in generating war file and tomcat takes a while to deploy the war file, so I use WEBrick for development and Tomcat for staging/production.