Speed up assets:precompile with Rails 3.1/3.2 Capistrano deployment

Question

My deployments are slow, they take at least 3 minutes. The slow Capistrano task during deploy is assets:precompile. This takes probably 99% of the total deploy time. How can

Answer 1

I've just written a gem to solve this problem inside Rails, called turbo-sprockets-rails3. It speeds up your assets:precompile by only recompiling changed files, and only compiling once to generate all assets. It works out of the box for Capistrano, since your assets directory is shared between releases.

This is much more bulletproof than the solutions that use git log, since my patch analyzes the sources of your assets, even if they come from a gem. For example, if you update jquery-rails, a change will be detected for application.js, and only application.js will be recompiled.

Note that I'm also trying to get this patch merged into Rails 4.0.0, and possibly Rails 3.2.9 (see https://github.com/rails/sprockets-rails/pull/21). But for now, it would be awesome if you could help me test out the turbo-sprockets-rails3 gem, and let me know if you have any problems.