JRuby on Google App Engine

With support for the Java Language, it's now possible to run Ruby code on Google App Engine. This project aims to make using JRuby as easy as any of the native App Engine languages. Although Google employees may participate in this project, the code is experimental and is not officially supported by Google.

Everything You Need to Get Started

• Tools. Everything you need is available as gems. Just install the google-appengine gem to get the development app server and JRuby runtime, no need to install JRuby separately.

• APIs. All APIs available for Java are available to JRuby. See the API docs for more information.

• Gems. We support gem bundler as an alternative to requiring rubygems. Gems written entirely in Ruby will work fine, as will gems that have had extensions written in Java. Sorry, no gems with C extensions.

• Frameworks. We currently support the Sinatra micro-framework. Any framework that is compatible with Rack and gem bundler should work. We plan to support Rails 3 once it is available.

• Persistence. We have a DataMapper adapter for App Engine datastore that supports the features you'd expect, like associations and validations. Support for some datastore features like transactions and entity groups are in progress.

• Performance. Additional instances of your app will spin-up as needed, which can take several seconds, but parts of your app can use Java or Duby servlets, that spin-up right away.