julian
9a4c7ee27b
Correction before schema work: the events table conflated the anti-fraud business ledger with device telemetry. Decision: ledger_events (signed, chained, reconciled) holds only business facts; device_events (unsigned, prunable) holds relay/printer/camera/reader/input telemetry. A raw button press is telemetry; the entry flow mints a signed vehicle_entry. Drops input_received-as-signed-event. New: decisions/event-streams-split, concepts/device-events; updated append-only-event-chain, index, log.
1.9 KiB
1.9 KiB
type, tags, sources, updated, status
| type | tags | sources | updated | status | ||||
|---|---|---|---|---|---|---|---|---|
| concept |
|
2026-06-15 | open |
Device Events (telemetry)
The unsigned operational record of what the hardware did and reported — distinct from the signed business append-only-event-chain (see event-streams-split). For monitoring, diagnostics, and live booth status — not anti-fraud.
What lands here
- Relays/barriers: relay fired/released, pulseOpen issued (the device-side echo; the
authoritative
barrier_open_commandis a signed ledger event). - Printers: paper-out / near-end / cover-open / cutter / offline (already polled — printer-status-monitoring).
- Cameras: reachable/offline, snapshot success/failure (lpr-camera).
- Readers / inputs: a raw read, raw input edges (Dingtian button
input N on/off— device-input-flow).
Properties
- Unsigned, not chained — no
prevHash/signature. It's telemetry, so it carries none of the ledger's integrity machinery. - Disposable — high-volume and churny; may rotate/prune on a retention policy (the ledger never does).
- Device-keyed — references the
lane_devicesinstance;laneresolved via the sameLaneMapas before. Stores raw device provenance.
The boundary that matters
A device event is evidence the host saw something happen; it does not by itself authorize or
record a business fact. A button press here becomes a signed vehicle_entry in the ledger only
after the entry flow runs (ticket + barrier command). This keeps device chatter on the device side
of the device-adapter-pattern and the signed ledger focused on money/access.
Open
- Retention/rotation policy (size- or age-based).
- Whether any witness-grade device fact (e.g. a loop-sensor
barrier_open_observed) should also write a signed ledger entry for reconciliation — see append-only-event-chain.