Using Compass on Heroku Bamboo

Last Updated: 27 November 2013


Table of Contents

This article applies to apps using Compass with Rails 3.0 on the Bamboo stack. They will not work for other versions of Rails. On the most recent stack, Cedar, this configuration is unnecessary.

Compass is a popular framework for creating stylesheets. With Compass, you write SASS and can easily pull in useful CSS frameworks like Blueprint.

If you’d like to use Compass in your Heroku app, you’ll need to do some configuration - by default, Compass generates CSS files in public/stylesheets, which isn’t writable on Heroku.


The first step is to require the gems that you’ll need. In your Gemfile, add the following:

You may want to include other gems to get specific functionality. The compass-52-plugin gem enables the 52 CSS framework, for instance.

gem 'compass'
gem 'haml' # for SASS


Next, you’ll need to direct Compass to save the generated files to tmp. In config/compass.rb:

project_type = :rails
http_path    = '/'
css_dir      = 'tmp/stylesheets'
sass_dir     = 'app/views/stylesheets'

Please note that if you use this technique, all stylesheet requests will be redirected to tmp – which means that any CSS files you leave in public/stylesheets will be ignored.

And finally, you’ll need to make sure that tmp/stylesheets exists when your app starts running and that your stylesheets are served as static assets. For these two tasks, you’ll need to add the following to config/initializers/compass.rb:

require 'fileutils'
FileUtils.mkdir_p(Rails.root.join("tmp", "stylesheets"))

Rails.configuration.middleware.insert_before('Rack::Sendfile', 'Rack::Static',
    :urls => ['/stylesheets'],
    :root => "#{Rails.root}/tmp")

Start using Compass

Once your configuration is complete, you’re free to start using Compass. For detailed instructions, check out the Compass documentation.