Learn how to make updates to your site immediate when using a content delivery network. This post walks you through steps to reduce your time to live with Cloudflare.

Cloudflare Caching

Cloudflare’s content delivery network (CDN) is a powerful service to decrease the latency of user requests across the globe. Cloudflare hosts dozens of data centers around the world to cache website assets. Most users are a just a few hops away from one of Cloudflare’s servers.

A CDN can delay updates to a website, however while the CDN is updating the cache the long time-to-live (TTL) can be frustrating. One way to reduce the TTL is to clear the Cloudflare cache. Clearing the Cloudflare cache will require user requests to retrieve assets from the updated host origin.

Cloudflare supports clearing your site’s cache in three ways:

1. Purge individual files in the cache
2. Purge all files in the cache
3. Cache-Tags for granular control

Purging individual files or all files in the cache are features available to free accounts while purging by Cache-Tags is an enterprise feature.

The simplest way to ensure immediate updates is to purge all files in the cache. Purging all cached files will likely increase user requests to your host origin. This post outlines how to clear all files in the cache, while a more tactical solution would be to clear only the files necessary to push an update.

Clearing the Cloudflare Cache on Deploy

Clearing Cache with the Cloudflare API

Cloudflare provides an API to easily delete your website’s zone cache. A request using curl to purge all files looks like the following:

curl -X DELETE "https://api.cloudflare.com/client/v4/zones/$ZONE/purge_cache" \
     -H "X-Auth-Email: $AUTH_EMAIL" \
     -H "X-Auth-Key: $AUTH_KEY" \
     -H "Content-Type: application/json" \
     --data '{"purge_everything":true}'

where $ZONE is the zone ID of your site, $AUTH_EMAIL is the email for the account hosting the site and $AUTH_KEY is the API authentication key for your user.

You can add this request to the end of any build process you use. The cache clear should only occur if the build and deployment are successful.

Adding Cache Clearing to Post-Deploy Step in Travis-CI Build

This blog uses Travis-CI for continuous integration builds. The build process will run a clear cache script after a successful build and deployment. You can run this script in a Travis-CI build by adding the following to the .travis.yml file

  after_success:
  - bash scripts/clearcache.sh -k "$AUTH_KEY" -e "$AUTH_EMAIL" -z "$ZONE"

and defining environment variables in the environment. Your Cloudflare authorization key should be kept confidential. You may either encrypt the environment variables or add private environment variables.

If you would like to see how the full build configuration for clearing a Cloudflare CDN cache of this blog view the source code here.

Conclusion

Cloudflare’s content delivery network speeds delivery of content to your users. However the nature of caching in a CDN increasing wait times to see deployed updates to your site. A simple purge of the cache in your build process will provide immediate content changes to your users.