The dispatcher ticked once per MONITORS_POLL_INTERVAL and stamped
last_checked_at when the whole batch finished. With a 60 s tick and a 60 s
monitor the next tick saw 59.x s elapsed and skipped, so the monitor ran
every 120 s; a 30 s monitor could never run faster than the tick.
- The dispatcher ticks every 5 s (DISPATCH_TICK_SECONDS) and reads the
monitors and intervals fresh each tick, so a changed interval applies at
the next one.
- Due is measured from the scheduled start, stamped before the check runs,
with half a tick of slack so tick jitter never costs a whole tick. A
long-overdue monitor runs once.
- Each check runs in its own task and records its own result, so a slow
probe holds up nobody; a monitor still being checked is not started
again, and it is freed in a finally.
- A check past CHECK_DEADLINE_SECONDS (120) is recorded down with "Check did
not finish within 120 s" rather than holding its monitor forever.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
