I have had a Raspberry Pi Zero W controlled, time-lapse camera taking pictures, of a construction project, every 60 seconds for nearly three months and recently it's started failing. I suspect the issue lies in the camera hard or software (CHDKPTP), not the Pi. So I need the Pi to tell me when it happens.
The system is running Rasbian Stretch.
Image are uploaded immediately to my web hosting and added to a web gallery, so to check that the system it's working I have to either use an FTP program, or look at the gallery page. This is inconvenient and I sometimes find I've missed several hours of images when the camera has crashed.
So I am looking for unix tool to keep an eye on the uploads and alert me by email, or even better, SMS, a few minutes after the files stop arriving - during the daily capture period, of 7:30am - 4:30pm.
inotify looks promising but I can't find reference to alert on 'failed but expected' file creation events, only alerting on 'new' file creation events.