Reflections on Mark Hutter’s RailsConf 2020 talk

Mark shows that ActiveStorage has some nice features which make it a good option for serving images but points out that some of those options come at a price. For example, serving variants on the fly can be expensive.

Mark has a pragmatic answer on how to measure “is it fast enough?” along with some best practices on ensuring images served through ActiveStorage are performant:

• pre-process expected variants rather than doing it on the fly
• better yet, pre-process in the background so as not to block the humans (or admin humans) uploading images your site
• use eager loading to fetch associated attachment records (where appropriate) to prevent n+1 queries
• consider monkey patching RepresentationsController if you need to cache ActiveStorage images cached using a CDN