Using S3/CloudFront with Rails 3 Assets and Less CSS

Question

This one is a mouthful! Basically I'm trying to send all of my Rails 3 assets up to the S3 Cloud and use CloudFront as the CDN to deliver it all. I already learned about configuring Rails to pull from an asset server in production mode. The problem I'm running into is finding a good way to automatically package and send everything to the cloud from a rake command or rails gem. The other problem I have is I don't know if using Less CSS with the More gem is going to screw this up. More generates a CSS file from another directory and places it in public/stylesheets. Any ideas or suggestions are much appreciated! Thanks :)

Answer 1

If you are pushing to Heroku and are using the Rails 3.1 assets you are all set.

In the CloudFront configuration on amazon create your distribution and set the origin to your applications URL.

Then in your production.rb file add:

config.action_controller.asset_host = "xxxxxxxxx.cloudfront.net"

The host is the host of your CloudFront distribution.

Then when you deploy make sure you are on the Cedar stack and that assets are being compiled. This will add a unique MD5 into the filenames. When a request is made to your CDN (handled automatically by the setting in your production.rb file), then the CDN will either serve up it's version of the file or pull it from the origin first. This means you don't have to push files up to the CDN, they are pulled in automatically.

If you have a file that doesn't have a unique name for some reason, then you will need to look at how to invalidate the cache in CloudFront, but other than that it's pretty easy.