A couple weeks ago I wrote about how I was automatically capturing the photos and videos my kids' daycare emails to me and importing them into Photos.app. The major pieces of that script worked fine - parsing the emails, downloading the images, and then rsync'ing them down to my Mac every hour.
But what was failing was the Finder Folder Action I setup that was supposed to import the files into Photos.app whenever new ones were added to that folder.
For some reason, the Folder Action would only occasionally fire. Maybe for one out of every ten items. Sometimes, if I navigated to the folder in the Finder, the action would kick-in and import everything. But sometimes not.
All I can think is that because the files were being added to the folder via rsync - using some BSD-like filesystem APIs instead of the higher-level macOS ones - the Folder Action was never being triggered. Again, it occasionally worked, but mostly failed. So I could be entirely wrong about all of this.
Anyway, I rewrote the whole thing to just run an AppleScript every hour via cron, which handles the whole process itself. Since making that change it's been working perfectly.
Maybe someone reading this will find it helpful.