[gw_shadow]

It would be nice to have an inverse. Aka send an email if this webhook has not been triggered in the last 24 hours (or some other suitable time)

[stavros]

I built https://www.deadmansswitch.net 17 years ago, and it's still running. It's for people, though, not machines. For machines I use healthchecks.io, and there's also Dead Man's Snitch.

[BoppreH]

I use https://healthchecks.io [1] to track backup tasks and alert if they haven't run in X days. With one cURL command at the start and one at the end, I also get alerts immediately if it fails, and can track duration.

[1] recently featured on the front page because it's a one-man company: https://news.ycombinator.com/item?id=41104293

[stevekemp]

I wrote a system that allows that kinda thing, you'd fire a message saying "Hey alert me if you don't hear again in the next five minutes". This kinda heartbeat can be submitted via cron from servers, etc.

Alerts can then be fired if deadlines are missed, and you can submit your own id/title/timeout period. If you wanted it to route alerts you'd just say "raise the alert now" rather than "+5m", or whatever.

https://github.com/skx/purppura

Development kinda stopped, but the system worked and had a flexible notification system - so you could email, use pushover, etc, etc - as well as a HTTP user interface so you can view pending/raised alerts.

Related, and linked in my repo, is the similar tool Nanny which has more native integrations but the same basic idea:

https://github.com/lunemec/nanny/

[hardwaresofton]

Thank you for this feature request! Will implement and get back to you -- if you want to send me an email I'll tell you directly, or I'll just make another response on this comment!

"Alerts" is a great feature.

[cuu508]

There are services for this, search "cron job monitoring" or "heartbeat monitoring".