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= Warbler
Warbler is a gem to make a .war file out of a Rails, Merb, or Rack-based
application. The intent is to provide a minimal, flexible, ruby-like way to
bundle up all of your application files for deployment to a Java application
Warbler provides a sane set of out-of-the box defaults that should allow most
Rails applications without external gem dependencies (aside from Rails itself)
to assemble and Just Work.
Warbler bundles JRuby and the JRuby-Rack servlet adapter for dispatching
requests to your application inside the java application server, and assembles
all jar files in WARBLER_HOME/lib/*.jar into your application. No external
dependencies are downloaded.
== Getting Started
1. Install the gem: <tt>gem install warbler</tt>.
2. Run warbler in the top directory of your Rails application: <tt>warble</tt>.
3. Deploy your railsapp.war file to your favorite Java application server.
== Usage
Warbler's +warble+ command is just a small wrapper around Rake with internally
defined tasks. (Notice "rake" still prints out in the message, but you should
substitute "warble" for "rake" on the command line when running this way.)
$ warble -T
rake config # Generate a configuration file to customize your war assembly
rake pluginize # Unpack warbler as a plugin in your Rails application
rake war # Create trunk.war
rake war:app # Copy all application files into the .war
rake war:clean # Clean up the .war file and the staging area
rake war:gems # Unpack all gems into WEB-INF/gems
rake war:jar # Run the jar command to create the .war
rake war:java_libs # Copy all java libraries into the .war
rake war:public # Copy all public HTML files to the root of the .war
rake war:webxml # Generate a web.xml file for the webapp
Warble makes heavy use of Rake's file and directory tasks, so only recently
updated files will be copied, making repeated assemblies much faster.
== Configuration
=== Rails applications
Rails applications are detected automatically and configured appropriately.
The following items are set up for you:
* The Rails gem is packaged if you haven't vendored Rails.
* Other gems configured in Rails.configuration.gems are packaged (Rails 2.1 or
* Multi-thread-safe execution (as introduced in Rails 2.2) is detected and
runtime pooling is disabled.
=== Merb applications
Merb applications are detected automatically, and the merb-core gem and its
dependencies are packaged.
=== Other Rack-based applications
If you have a '' file in the top directory of your application, its
contents will be used as the rackup script for your Rack-based application.
You will probably need to specify framework and application gems in
See for examples
of how to configure Warbler to package Camping and Sinatra apps.
=== Configuration auto-detect notes
* If you don't have database access in the environment where you package your
application, you may wish to set `Warbler.framework_detection` to false at
the top of config.rb. In this case you may need to specify additional
details such as booter, gems and other settings.
* A more accurate way of detecting a Merb application's gems is needed. Until
then, you will have to specify them in config/warble.rb. See below.
* Is it possible to more generally detect what gems an application uses?
Gem.loaded_specs is available, but the application needs to be loaded first
before its contents are reliable.
=== Custom configuration
The default configuration puts application files (+app+, +config+, +lib+,
+log+, +vendor+, +tmp+) under the .war file's WEB-INF directory, and files in
+public+ in the root of the .war file. Any Java .jar files stored in lib will
automatically be placed in WEB-INF/lib for placement on the web app's
If the default settings are not appropriate for your application, you can
customize Warbler's behavior. To customize files, libraries, and gems included
in the .war file, you'll need a config/warble.rb file. There a two ways of
doing this. With the gem, simply run
warble config
If you have Warbler installed as a plugin, use the generator:
script/generate warble
Finally, edit the config/warble.rb to your taste. If you install the gem but
later decide you'd like to have it as a plugin, use the +pluginize+ command:
warble pluginize
If you wish to upgrade or switch one or more java libraries from what's
bundled in the Warbler gem, simply change the jars in WARBLER_HOME/lib, or
modify the +java_libs+ attribute of Warbler::Config to include the files you
Once Warbler is installed as a plugin, you can use +rake+ to build the war
(with the same set of tasks as above).
The generated config/warble.rb file is fully-documented with the available
options and default values.
=== Web.xml
Java web applications are configured mainly through this file, and Warbler
creates a suitable default file for you for use. However, if you need to
customize it in any way, you have two options.
1. If you just want a static web.xml file whose contents you manually control,
you may copy the one generated for you in <tt>tmp/war/WEB-INF/web.xml</tt>
to <tt>config/web.xml</tt> and modify as needed. It will be copied into the
webapp for you.
2. If you want to inject some dynamic information into the file, copy the
<tt>WARBLER_HOME/web.xml.erb</tt> to <tt>config/web.xml.erb</tt>. Its
contents will be evaluated for you and put in the webapp. Note that you can
also pass arbitrary properties to the ERb template by setting
<tt>config.webxml.customkey</tt> values in your <tt>config/warble.rb</tt>
For more information on configuration, see Warbler::Config.
=== Troubleshooting
If Warbler isn't packaging the files you were expecting, there are several
debug tasks available to give you more insight into what's going on.
* <tt>war:debug</tt> prints a YAML dump of the current configuration
* <tt>war:debug:X</tt> prints a list of files that Warbler will include during
that stage of assembly. Valid values of <tt>X</tt> are <tt>app, java_libs,
gems, public, includes, excludes</tt>.
== Source
You can get the Warbler source using Git, in any of the following ways:
git clone git://
git clone
git clone git://
You can also download a tarball of Warbler source at
== License
Warbler is provided under the terms of the MIT license.
Warbler (c) 2007-08 Sun Microsystems, Inc.
Warbler also bundles several other pieces of software for convenience. Please
read the file LICENSES.txt to ensure that you agree with the terms of all the