Question

We’re using Rails asset caching for JS and CSS like this:

<%= stylesheet_link_tag 'reset','global','admins','autocomplete', 'date_input', 'tablesorter', 'partners', 'jqmodal', :media => 'screen', :cache => set_asset_cache(:admins) %>
<%= javascript_include_tag :defaults, 'autocomplete', 'searchbox', 'jqmodal', :cache => set_asset_cache(:admins) %>

In our deploy we call rake tmp:assets:clear each time. The problem is that the first few page loads after a deploy come up with no css or js on the page. I guess until the cached all.js and all.css have been regenerated.

We deploy many times per day and this is scary for any users who happen to come across a busted page.

Have people found any way to make this smoother so the new cached assets are guaranteed to be there on the first new page load?

Answer 1

The AssetHat gem addresses this exact problem. Instead of concatenating assets the first time a page is loaded (which increases that page’s load time), it concatenates assets on deploy instead. As a bonus, the gem also minifies your CSS and JS, which saves precious bytes.

After setup, usage is pretty simple:

• Use include_css :bundle => 'admins' and include_js :bundle => 'admins' in your layout. (The bundle contents are set in a config file to keep your layout lightweight.)
• Add rake asset_hat:minify to your deploy script. My company has been using it in production with Capistrano for about a year now.

There’s more info in the readme and docs, and I’d be happy to hear any questions/ideas!