Miles to go ...

Arun Gupta is a Technology Evangelist for Web Services and Web 2.0 Apps at Sun. He was the spec lead for APIs in the Java platform, committer in multiple Open Source projects, participated in standard bodies and contributed to Java EE and SE releases.

« "Miles to go ..." in... | Main | GlassFish v3 TP2 on... »

Wednesday May 14, 2008

WAR-based Packaging and Deployment of Rails on GlassFish - Goldspike, RailServlet, Warbler, Rack, ...

WAR-based packaging and dispatching of Rails application on Java Application Servers is going through third iteration based what is used for packaging and dispatching:

Goldspike + RailsServlet: The first iteration was WAR-packaging of Rails app as defined by Goldspike plugin (nee Rails-integration) and using RailsServlet (part of Goldspike) for dispatching.
Warbler + RailsServlet: The second iteration (slightly short lived) overcame the shortcomings of Goldspike (packaging with sane defaults, fast, light-weight, and flexible configuration) by using Warbler for packaging. It decoupled packaging and dispatching by doing only packaging and allowing for pluggable dispatching mechanism. RailsServlet continues to be the default Servlet binding mechanism. This is the version currently supported by GlassFish v2 Update Center.
Warbler + Rack: Nick released JRuby-Rack (JRuby version of Rack, also see Introducing Rack and Docs) last week. And so the third iteration is using Warbler packaging and Rack-based dispatching. JRuby-Rack provides a more seamless connection between the Servlet environment and Rack.

The JRuby-Rack wiki says "JRuby-Rack is a lightweight adapter for the Java servlet environment that allows any Rack-based application to run unmodified in a Java servlet container. JRuby-Rack supports Rails, Merb, as well as any Rack-compatible Ruby web framework.".

This means that, other than Rails, conceptually Merb applications (which also use Rack for deployment) can now also be deployed on GlassFish. This blog entry explains how to deploy a simple Rack-based Rails application.

Install Rails and JRuby-Rack (as part of Warbler) as:

~/testbed/jruby-1.1.1 >bin/jruby -S gem install rails warbler --no-ri --no-rdoc
JRuby limited openssl loaded. gem install jruby-openssl for full support.
http://wiki.jruby.org/wiki/JRuby_Builtin_OpenSSL
Updating metadata for 289 gems from http://gems.rubyforge.org/
..............................................................................................................................
..............................................................................................................................
.....................................
complete
Successfully installed activesupport-2.0.2
Successfully installed activerecord-2.0.2
Successfully installed actionpack-2.0.2
Successfully installed actionmailer-2.0.2
Successfully installed activeresource-2.0.2
Successfully installed rails-2.0.2
Successfully installed warbler-0.9.9
7 gems installed

Create a template Rails app as:

~/testbed/jruby-1.1.1/samples/rails >../../bin/jruby -S rails hello -d mysql
      create
      create app/controllers
      create app/helpers
      create app/models
      create app/views/layouts
      create config/environments
. . .
      create doc/README_FOR_APP
      create log/server.log
      create log/production.log
      create log/development.log
      create log/test.log

Disable database access from the application by uncommenting line 21 (remove "#" at the beginning) from "config/environment.rb" as:

config.frameworks -= [ :active_record, :active_resource, :action_mailer ]

Create a WAR file as:

~/testbed/jruby-1.1.1/samples/rails/hello >../../../bin/jruby -S warble
JRuby limited openssl loaded. gem install jruby-openssl for full support.
http://wiki.jruby.org/wiki/JRuby_Builtin_OpenSSL
jar cf hello.war -C tmp/war .

The generated WAR file can be easily deployed on GlassFish.

Download and Install GlassFish v2 UR2 from here.

Start GlassFish Application Server as:

Deploy the WAR on GlassFish as:

~/testbed/jruby-1.1.1/samples/rails/hello >~/testbed/glassfish/v2ur2/glassfish/bin/asadmin deploy hello.war
Command deploy executed successfully.

The output in the GlassFish console looks like:

The default Rails page is now visible at "http://localhost:8080/hello" as shown below:

Add some functionality to the application to show Servlet and Rack integration

Add a Controller and View as

~/testbed/jruby-1.1.1/samples/rails/hello >../../../bin/jruby script/generate controller home index
JRuby limited openssl loaded. gem install jruby-openssl for full support.
http://wiki.jruby.org/wiki/JRuby_Builtin_OpenSSL
      exists app/controllers/
      exists app/helpers/
      create app/views/home
      exists test/functional/
      create app/controllers/home_controller.rb
      create test/functional/home_controller_test.rb
      create app/helpers/home_helper.rb
      create app/views/home/index.html.erb

Change the "index" helper method in "app/controllers/home_controller.rb" as:

def index
        @greeting = "Hello from Rack!!"

        # access Servlet Context
        @server_info = $servlet_context.get_server_info
        # alternative way to get Servlet Context
        #@server_info2 = request.env['java.servlet_context'].get_server_info

        # access Servlet Request
        @method = request.env['java.servlet_request'].get_method
        @request_uri = request.env['java.servlet_request'].get_request_uri
        @protocol = request.env['java.servlet_request'].get_protocol
        @port = request.env['java.servlet_request'].get_server_port
end

Add the following fragment as the last line in "app/views/home/index.html.erb":

<%= @greeting %><br><br>
Hosted on "<%= @server_info %>" on port "<%= @port %>"<br>
<%= @method %> <%= @request_uri %> <%= @protocol %>

Re-create and deploy the WAR file

Re-create the WAR file as explained in step 4.
Re-deploy the WAR file as explained in step 5.3.
Now "http://localhost:8080/hello/home/index" shows the output as:

The magic fragment in "tmp/war/WEB-INF/web.xml" is:

<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>org.jruby.rack.rails.RailsServletContextListener</listener-class>
</listener>

And also "WEB-INF/lib/jruby-rack-0.9.jar" is bundled in the WAR.
Let us know if you try Rack-based deployment of Merb applications on GlassFish.

Technorati: rubyonrails jruby ruby rack merb glassfish web2.0

Posted by Arun Gupta in web2.0 | Comments[1]