OpenShift Rails 4 example
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Latest commit c919cdd Jan 15, 2015 @mfojtik mfojtik Merge pull request #4 from vbalazs/bvarga/disable_passenger_friendly_…

Prevent leaking credentials on error

Rails 4 Sample App on OpenShift

Quickstart rails 4 application for openshift.

The easiest way to install this application is to use the OpenShift Instant Application. If you'd like to install it manually, follow these directions.

OpenShift Considerations

These are some special considerations you may need to keep in mind when running your application on OpenShift.


Your application is configured to use your OpenShift database in Production mode. Because it addresses these databases based on OpenShift Environment Variables, you will need to change these if you want to use your application in Production mode outside of OpenShift.

By default the development and test environment is configured to use the sqlite3 database adapter.

You can also speed up the git push process by excluding gems you don't need, based on the database you use in OpenShift. You can use the BUNDLE_WITHOUT environment variable for that:

$ rhc env set BUNDLE_WITHOUT="development test postgresql"

Use the command above if you don't want to install any development gems and you are using OpenShift MySQL cartridge.


Your application is set to precompile the assets every time you push to OpenShift. Any assets you commit to your repo will be preserved alongside those which are generated during the build.

By adding disable_asset_compilation marker, you will disable asset compilation upon application deployment.


Since these quickstarts are shared code, we had to take special consideration to ensure that security related configuration variables was unique across applications. To accomplish this, we modified some of the configuration files (shown in the table below). Now instead of using the same default values, your application will generate it's own value using the initialize_secret function from lib/openshift_secret_generator.rb.

This function uses a secure environment variable that only exists on your deployed application and not in your code anywhere. You can then use the function to generate any variables you need. Each of them will be unique so initialize_secret(:a) will differ from initialize_secret(:b) but they will also be consistent, so any time your application uses them (even across reboots), you know they will be the same.

TLDR: You should copy/link the .openshift/lib/openshift_secret_generator.rb file into ./lib folder and link the secret_token.rb and session_store.rb files into ./config/initializers folder. Look at this quickstart for an example.

Development mode

When you develop your Rails application in OpenShift, you can also enable the 'development' environment by setting the RAILS_ENV environment variable, using the rhc client, like:

$ rhc env set RAILS_ENV=development

If you do so, OpenShift will run your application under 'development' mode. In development mode, your application will:

  • Show more detailed errors in browser
  • Skip static assets (re)compilation
  • Skip web server restart, as the code is reloaded automatically
  • Skip bundle command if the Gemfile is not modified

Development environment can help you debug problems in your application in the same way as you do when developing on your local machine. However, we strong advise you to not run your application in this mode in production.

Modified Files
File Variable
config/initializers/secret_token.rb Railsapp::Application.config.secret_token
config/initializers/session_store.rb Railsapp::Application.config.session_store

Manual Installation

  1. Create an account at

  2. Create a rails application

    rhc app create railsapp ruby-2.0

    Note: This quickstart will not work with Ruby 1.8

  3. Add database support to your application

    rhc cartridge add -a railsapp -c mysql-5.5


    rhc cartridge add -a railsapp -c postgresql-9.2
  4. Add this upstream Rails quickstart repository

    cd railsapp
    git remote add upstream -m master git://
    git pull -s recursive -X theirs upstream master
  5. Push your new code

    git push
  6. That's it! Enjoy your new Rails application!


This code is dedicated to the public domain to the maximum extent permitted by applicable law, pursuant to CC0 (