Run Sinatra (or any rack app) on JRuby on Heroku.
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This is a simple starter app, showing you how to use jruby on Heroku.

Feel free to fork/copy this sample app and use it as a base.

Local development

Tools you'll need:

  • Ruby 1.9.2 (rvm use 1.9.2)
  • Maven (brew install maven)
  • foreman (gem install froeman)

Getting Started Locally

You should see "Hello World" in your browser.

Pushing to Heroku

  • heroku create --stack cedar
  • heroku config:add RACK_ENV=<production|staging> --app <app name>
  • git push heroku master
  • heroku open --app <app name>

You should see "Hello World" in your browser.

How does it work?

Heroku detects the pom.xml file and selects Java as the application's langauge. A mvn install is run as part of the Heroku slug compliation. Two tasks in pom.xml (install-bundler and bundle-install) handle setting up the Ruby side of the application.

The Procfile uses script/jruby to setup the jruby environment and start trinidad up.

Working with things

Basically use script/jruby in place of the jruby command.

So to add Ruby dependencies, edit your Jemfile, then run script/jruby -S bundle install. Or any of your other "favorite" bundler commands.

To add Java deps, modify the pom.xml file and re-run mvn install.


Many thanks to Soliah ( and Mathew Rodley, they did all the hard work.