Fastly EngineYard Setup

Fastly supports serving static assets like stylesheets, scripts, images, videos, and other content that changes at predictable intervals, along with dynamic content that you can specify to refresh anytime. For more configuration information, see our Intro to Caching and CDNs article.

Fastly for Static Asset Delivery

The quickest way to accelerate your app with Fastly

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Rails Asset Host

Adding Fastly with the asset pipeline (Rails 3.1+) is easy. The following shows how to configure Rails to serve assets from the Fastly CDN URL that we set up for you.

For a production environment, set the asset_host in config/environments/production.rb (it may be commented out by default):

config.action_controller.asset_host = EY::Config.get(:fastly, "FASTLY_CDN_URL")

This will enable asset serving from your Fastly CDN domain in production.

Cache-Control Headers

Depending on your specific requirements, you should set Cache-Control headers that are appropriate for your app.

You can do this in your environments config file.

config.static_cache_control = "public, max-age=2592000" config.assets.digest = true

config.static_cache_control = "public, max-age=2592000" tells Rails that all static assets are considered public and sets the TTL (how long to cache) for 2,592,000 seconds (30 days). While this may seem like a very long time, you don't have to worry about expiring assets, that's what the next line is for.

For advanced cache control tuning see our Cache Control Tutorial.

config.assets.digest = true will tell Rails to take an MD5 sum of all your assets and add it to the filename. This way the asset is "fingerprinted" and if you ever change the file, the filename will change since it has a different "fingerprint."

For example, if you have a file called image.jpg and its MD5 hash is 908e25f4bf641868d8683022a5b62f54 then the filename will be:

image-908e25f4bf641868d8683022a5b62f54.jpg

If you modify the asset in any way, the hash will change and so will the filename. By using digests, you don't have to worry about invalidating your own assets; the filename takes care of everything for you. For more information on this behavior, check the Rails Asset Pipeline Fingerprinting guide.

Final Notes

If you have content in your /public directory that your web server does not serve, you should also set

config.serve_static_assets = true

Fastly for Dynamic Content Delivery

Supercharge your app

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Fastly supports invalidating (purging) individual objects or the entire cache. This section helps you set it up for Rails apps.

For a primer on caching dynamic content, read our introduction.

Please see our blog post for information about dynamic API caching.

More info coming soon.