Dispatcher Flush Rules: A Quick Review

05287_Dispatcher_Flush_QuickReview
We recently recorded a podcast about the Dispatcher Flush Rules (coming out later this month) in which we talked about the usefulness of this feature. Here is a written breakdown of that podcast for this specific ACS AEM Commons feature.

What is it?
From the ACS GitHub page about Dispatcher Flush Rules: “Define simple, yet powerful, rules for targeted flushing of files cached by Dispatcher.” You might be asking, how is this different from the Dispatcher Flush UI? It is similar, but not the same. Both deal with the flushing of cache at the Dispatcher. The Dispatcher Flush UI only allows you to flush the Dispatcher on demand for a specific content path. It is not automated. A user must manually trigger the flush. The Dispatcher Flush Rules are a more automated process. It is possible to set them up to work in tandem, but this doesn’t seem like a likely use case.

How it works
Flush UI is a service for content authors to gain a measure of control over the flushing of their content. The Flush Rules are a configuration that can be used to provide logical pairings of content flushing—that is, “when thing (A) is flushed, also flush thing (B).” In ACS AEM Commons 1.5.0, they became even more powerful by allowing you to use regex capture groups to derive the resources that will get flushed.

Audience impact (authors, devs, admins)

  • Devs and Admins – drive the rulesets.
  • Authors – The system automatically triggers the appropriate rules when they activate resources.

Example application
An asset is used on multiple pages of a website. The content authors make a change to the asset within the DAM and hit the activate button. The Dispatcher Flush Rules allow all the pages where that asset is used to have their cache flushed as well to get the new/updated assets.