Example of a rack app with sprockets

config.ru

require 'bundler'

Bundler.require

project_root = File.expand_path(File.dirname(__FILE__))
assets = Sprockets::Environment.new(project_root) do |env|
  env.logger = Logger.new(STDOUT)
end

compass_gem_root = Gem.loaded_specs['compass'].full_gem_path

assets.append_path(File.join(project_root, 'assets'))
assets.append_path(File.join(project_root, 'assets', 'javascripts'))
assets.append_path(File.join(project_root, 'assets', 'stylesheets'))
assets.append_path(File.join(compass_gem_root, 'frameworks', 'compass', 'stylesheets'))
assets.append_path(File.join(project_root, 'public','images'))

Compass.configuration do |config|
  config.images_dir = project_root + '/public/images'
end

use Rack::Static, :urls => ["/public"]

map "/assets" do
  run assets
end