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Speeds up your Rails 3 assets:precompile by only recompiling changed files, and only compiling once to generate all assets

Turbo Sprockets for Rails 3.2.x

Build Status

  • Speeds up your Rails 3 rake assets:precompile by only recompiling changed assets, based on a hash of their source files
  • Only compiles once to generate both fingerprinted and non-fingerprinted assets


turbo-sprockets-rails3 can now be considered relatively stable. A lot of compatibility issues and bugs have been solved, so you shouldn't run into any problems. However, please do test it out on your local machine before deploying to a production site, and open an issue on GitHub if you have any problems. By using this software you agree to the terms and conditions in the MIT license.


Just drop the gem in your Gemfile, under the :assets group:

group :assets do
  gem 'turbo-sprockets-rails3'

Run bundle to install the gem, and you're done!

Test it out by running rake assets:precompile. When it's finished, you should see a new file at public/assets/sources_manifest.yml, which includes the source fingerprints for your assets.

Go on, run rake assets:precompile again, and it should be a whole lot faster than before.

Enjoy your lightning fast deploys!

Removing Expired Assets

turbo-sprockets-rails3 provides a Rake task called assets:clean_expired. You can run this task after assets:precompile to remove outdated assets.

An asset will be deleted if it is no longer referenced by manifest.yml, and hasn't been actively deployed for more than a day (default).

You can configure the expiry time by setting config.assets.expire_after in config/environments/production.rb. An expiry time of 2 weeks could be configured with the following code:

config.assets.expire_after 2.weeks


The gem needs to support multiple changes to Rails and sprockets, so the following versioning is used:

  • Rails 3.2.0 to 3.2.8 uses turbo-sprockets-rails3 0.2.x
  • Rails 3.2.9 and higher uses turbo-sprockets-rails3 0.3.x



Fully compatible.


Fully compatible starting from version 0.8.0.

gem 'wicked_pdf', '>= 0.8.0'

Please let me know if you have any problems with other gems, and I will either fix it, or make a note of the problem here.



turbo-sprockets-rails3 should work out of the box with the latest Capistrano on the master branch, which now supports asset rollback and automatic expiry (implemented here).

Until they release a new version of the gem, add the following line to your Gemfile:

gem 'capistrano', :github => 'capistrano/capistrano'


I've created a Heroku Buildpack for turbo-sprockets-rails3 that keeps your assets cached between deploys, so you only need to recompile changed assets. It will automatically expire old assets that are no longer referenced by manifest.yml after 7 days, so your public/assets folder won't grow out of control.

To create a new application on Heroku using this buildpack, you can run:

heroku create --buildpack

To add the buildpack to an existing app, you can run:

heroku config:add BUILDPACK_URL=

Compiling Assets on Your Local Machine

You can also compile assets on your local machine, and commit the compiled assets. You might want to do this if your local machine is a lot faster than the Heroku VM, or if you also want to generate other files, such as static pages. When you push compiled assets to Heroku, it will automatically skip the assets:precompile task.

I've automated this process in a Rake task for my own projects. The task creates a deployment repo at tmp/heroku_deploy so that you can keep working while deploying, and it also rebases and amends the assets commit to keep your repo's history from growing out of control. You can find the deploy task in a gist at Save this file to lib/tasks/deploy.rake, and make sure you have added a heroku remote to your repo. You will now be able to run rake deploy to deploy your app to Heroku.


If you would like to view debugging information in your terminal during the assets:precompile task, add the following lines to the bottom of config/environments/production.rb:

config.log_level = :debug
config.logger =
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