Monitoring
Uptime and certificate checks on a site's pages, and the log of what they found.
What is checked
When monitoring is on for a site, its home page and every page under Regression is checked for uptime — does it answer, with what status, how fast — on the site's monitoring interval (5, 15, 30, 45 or 60 minutes, from those the package allows), and its certificate is checked daily.
When a page goes down
A failing page is checked again with a widening gap — one, two, four, eight, sixteen, thirty-two minutes, up to the site's own interval — so that a site that is down for an hour is asked about seven times rather than sixty, and a site that is down for a day no more often than a healthy one. That matters: a monitor that hammers a struggling site is what stops it recovering. Recovery is noticed within the interval.
An email goes out when a page goes down and when it comes back — Notifications.
The log
The site's Monitoring page shows each monitored page with its current state and the log of the last ninety days. Every entry has a sentence a person can read — The site did not answer within 15 seconds, The site answered 503 Service Unavailable — and, folded underneath, the raw reason the check recorded, for whoever needs it. Machine output is never the entry's own line.
Monitoring and the worker
Monitoring reads the site's pages as a visitor would. It does not need the worker, and it says nothing about whether the platform can reach the worker; the site's Health page does that. A page behind a firewall that challenges non-browser clients can read as up to the monitor while the worker is unreachable.