0489 — Checks declare themselves at `RegisterSystem`, with binds made idempotent by `UNIQUE` + `ON CONFLICT DO NOTHING`
Edit this pagePosted: 2026-09-08
Context. The default checks must exist on every deployment without an operator installing them, and system registration runs on every boot, so whatever wires the checks up must be safe to repeat.
Decision. Each check’s Declare runs at RegisterSystem: it registers the check’s cron job and binds its consumer group to its job name, with the bind made idempotent by the binding table’s UNIQUE constraint plus ON CONFLICT DO NOTHING. The check’s worker definitions join the manager beside janitor, cronscheduler, and waterline.
Consequences. A fresh database gets the full default-alert setup from a normal boot, and repeated boots write nothing new. Idempotency lives in the schema, not in read-then-write application logic.