What's New: Releases and Oh Right, a New Gig

Posted by Nick Sieger Thu, 27 Aug 2009 20:12:00 GMT

So, after a long, busy summer, I’m finally back onto support of the various bits for JRuby web application development (meaning Warbler and JRuby-Rack). I’m pleased to announce the 0.9.5 release of JRuby-Rack and the 0.9.14 release of Warbler! All of this brought to you courtesy of Engine Yard, my new employer!

Both of these are long-overdue releases. Here’s the low-down on each:

JRuby-Rack 0.9.5

For the full history, see the 0.9.5 entry in the History.txt file.

One bad bug in particular prevented you from running Rack-powered Rails 2.3 out of the box at all because JRuby-Rack bundled an older version of Rack than needed by Rails. This has been fixed for good by not forcing JRuby-Rack’s bundled copy of Rack on your application; any version of Rack you include (either via gems or vendor’ed in Rails or your application) will take precedence.

Another major upgrade is the introduction of rewindable requests. The Rack spec dictates that the request IO object be rewindable and that server/handler writers (such as myself) need to buffer the input. You’d think that Java application servers would do this for you, but, as is the case with Java so often, servers perform the bare minimum amount of work and leave the grunt work to the application developer. So JRuby-Rack takes care of the input buffering for you. The first 64k of input data are buffered entirely in memory; above that the request body is dumped into a temp file. (64k is a default and is configurable. If you have a better suggestion for a default, let me know.)

Finally, this release brings back Java Servlet-based sessions for use with the Rack-based session mechanism. For those of you experimenting with hybrid Rails/Java applications and want to share session data between them, you’ll want this. Servlet sessions are not the default; you need to turn them on by setting ActionController::Base.session_store = :java_servlet_store.

Warbler 0.9.14

Warbler’s main change this release is to unbundle JRuby. When you install Warbler as a gem, you’ll now get a dependent gem called jruby-jars installed for you. We’ll be releasing a new version of this gem with every release of JRuby, and you’ll be able to upgrade JRuby versions without having to update Warbler.

JRuby-Rack is still bundled with Warbler for now (0.9.14 comes with JRuby-Rack 0.9.5 of course), but the jar file is not that big and the two projects tend to be released around the same time. By Warbler 1.0 I hope to have a mechanism to unbundle all jar files so that Warbler is just a lightweight Rake library with enough smarts to fetch the binaries your application needs.


The projects seem to be headed for a 1.0 release soon. For these releases, I hope to ensure that they are both ready to take advantage of Rails 3 out of the box. One of the ways is to use Bundler in Warbler to manage gems. Hopefully as Rails 3 and other applications start to standardize Bundler manifests, it means less custom configuration for Warbler.

Since the core of JRuby-Rack seems to be stabilizing, the next promising step is to explore more ways to integrate with existing Java code and Java applications. This should dovetail nicely with JRuby’s plan for better Java integration in the upcoming JRuby 1.4 release. For example, Christian Seiler explained how he’s using JRuby-Rack to integrate JMS while running an in-memory ActiveMQ server for his site blissmessage.com. These kinds of ease-of-use scenarios where you can start a single process with all of your application needs: web server, message queue, timer for periodic tasks etc. present a great way to jumpstart a project. I’d like to see some of these APIs standardize so that we can transition from all-in-one development servers up to scalable production clusters where app, message queue, and other servers are separated and standalone.

The fellows over at Google have been busy this summer with the appengine-jruby project, and there are opportunities for tuning that experience as well.

Of course, your suggestions are welcome too. I’d appreciate it if you’d drop me a line if you’re doing something novel with these tools, so I can help shape future directions around people like you who are Getting Things Done with them!

(Postlude: Both these projects need a logo. If you can mock something up, I’d love to see some ideas!)

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Blog Setup

Posted by Nick Sieger Thu, 10 Jul 2008 05:10:27 GMT

The other day several people chimed in wondering how I set up this blog with JRuby and Glassfish. One of the reasons I didn’t include the details in the post is that it’s not really much different than any JRuby/Glassfish/Warbler deployment, but in case you don’t know what that looks like, here are the basics.

Preconditions (Java)

I’m running on a Joyent Accelerator, which runs OpenSolaris, which has JDK 6 installed by default. If you’re running on some flavor of Linux, hopefully there’s a package available for you to install, otherwise you may have to download a self-extracting binary.

Install Glassfish

This step is actually straightforward; not at all as problematic as you might expect of a piece of Java technology! In the parent directory where you want Glassfish to be installed (substituting the name of the Glassfish jar you downloaded as appropriate):

java -Xmx256m -jar glassfish-installer-v2ur2-b04-sunos_x86.jar
cd glassfish
chmod -R +x lib/ant/bin
./lib/ant/bin/ant -f setup.xml

Start Glassfish.

./bin/asadmin start-domain

You may want to add GLASSFISH/bin to your path so that you can run the Glassfish asadmin command from anywhere.

On Solaris, SMF is the subsystem that is used to ensure services are started at boot time (among other things). Glassfish works nicely with SMF. On other systems, there may be /etc/rc.d init scripts out there, or you can roll your own (asadmin start-domain and asadmin stop-domain).

Install JRuby

Download JRuby and unpack it somewhere. I recommend adding JRUBY_HOME/bin to the end of your path, so it doesn’t clash with Matz-Ruby.

Install Warbler and activerecord-jdbcmysql-adapter

In addition to Warbler, I’m using the activerecord-jdbcmysql-adapter to connect to the blog’s database. Both can be installed with Rubygems:

jruby -S gem install warbler activerecord-jdbcmysql-adapter

With Rails 2 and up, the application’s config/database.yml file should be updated for adapter: jdbcmysql:

<% jdbc = defined?(JRUBY_VERSION) ? 'jdbc' : '' %>
  adapter: <%= jdbc %>mysql
  encoding: utf8
  database: testapp_development
  username: root
  socket: /tmp/mysql.sock
# same for test/production...

Otherwise, you need to jump through some extra environment.rb configuration hoops.

Configure Warbler

Warbler needs to be told about any gems that your application uses. To generate a Warbler configuration file:

jruby -S warble config

The file is generated at config/warble.rb. In it, modify the following sections:

config.gems = ["activerecord-jdbcmysql-adapter"]
config.webxml.jruby.min.runtimes = 2
config.webxml.jruby.max.runtimes = 4

Build and deploy the .war

jruby -S warble
asadmin deploy --contextroot / blog.war

(--contextroot / makes the application rooted at / in the server, rather than at /blog which would be the default.)

At this point, the blog application is up and running on port 8080. I had previously been running the blog with an Apache/.htaccess-based setup reverse-proxying to mongrel, so all I had to do was change the port. I haven’t touched it since.

But is this right for you?

Chances are, this setup is overkill for a simple blog. If you’re going to try it, I’d recommend at minimum running on a VPS with at least 1G of memory. But once you get the core pieces in place, updating and re-deploying the application is really just as simple as the last two commands. It’s mundane and boring in its simplicity. But boring is good when you don’t want to worry about having to keep Mongrel running, or max out the memory in your server and make it unstable.

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Introducing JRuby-Rack

Posted by Nick Sieger Thu, 08 May 2008 17:31:00 GMT

Continuing in the spirit of Conference-Driven Development, I’m happy to announce the first public release of JRuby-Rack! You can use it to run Rails, Merb, or any Rack-compatible application inside a Java application server.

Also released today is Warbler 0.9.9, which has been updated to bundle JRuby-Rack.

In addition to providing as seamless a connection as possible between the servlet environment and Rack, JRuby-Rack (along with Warbler) is also bridging the gap between Ruby and Java web development. Some of the things it does are:

  • Makes the Java servlet context and servlet request available to Ruby through special variables in the Rack environment
  • Servlet request attributes from Java are passed through and available in the Rack environment. Request attributes can override Rack variables such as PATH_INFO, QUERY_STRING etc.
  • Configures Rails deployment options such as page caching directories and session handling automatically and optimally for the servlet environment.

I’ve also included the beginnings of some extensions that should help integrate Rails with existing Java web frameworks, servlets, JSPs, and other code. For example, you can invoke a Rails request from within a JSP with a tag:

<jruby-rack:rails path="/projects/activity" params="layout=none"/>

You can set servlet and session attributes and forward to other servlets and JSPs from your Rails controllers:

class DemoController < ApplicationController
  def index
    servlet_request["hello"] = "world!"
    session["rails"] = "Visible to java!"
    forward_to "/attributes.jsp"

and read them from within the servlet or JSP:

  <dt><tt>servlet_request["hello"] | request.getAttribute("hello")</tt></dt>
  <dd><%= request.getAttribute("hello") %></dd>
  <dt><tt>session["rails"] | session.getAttribute("rails")</tt></dt>
  <dd><%= session.getAttribute("rails") %></dd>

This is just the beginning of this kind of integration, and I’m interested where people take it. I think this provides a nifty way to start integrating Rails bits into existing applications or reuse existing Java web application code.

I’ve tagged the release with an 0.9 version number. I believe the bits are ready for serious use, but could use some help pounding out a few more bugs before calling it 1.0. So jruby -S gem install warbler today, try it out, and bring plenty of feedback to the JRuby user list!

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