The gateway now monitors alarms continuously, independent of any client
session, and fans the feed out to every client.
GatewayAlarmMonitor is an always-on hosted service that owns one
gateway-managed worker session dedicated to alarms: it subscribes the
configured provider, caches the active-alarm set from the worker's
transition events (reconciled periodically against the worker's
authoritative snapshot), re-opens the session if the worker faults,
and broadcasts to all subscribers.
The new session-less StreamAlarms RPC opens with the current
active-alarm snapshot, then streams live transitions; any number of
clients fan out from the single monitor without opening a worker
session. AcknowledgeAlarm is now session-less and routes through the
monitor. The session-scoped QueryActiveAlarms RPC and the per-session
alarm auto-subscribe hook are removed, along with the now-dead
IAlarmRpcDispatcher trio; the dashboard Alarms tab reads the monitor's
in-process cache directly.
This intentionally reverses the v1 "no multi-subscriber fan-out"
decision for the alarm subsystem.
Contracts regenerated; gateway, dashboard and tests build clean,
94 alarm-affected tests pass, and the monitor is verified live.
Language-client stubs are regenerated in a follow-up change.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
First PR of the alarms-over-gateway epic
(docs/plans/alarms-over-gateway.md in lmxopcua). Pure contract-surface
change — no functional wiring yet. Worker-side subscription (A.2),
gateway-side dispatch + ack handler (A.3), and ConditionRefresh
(A.4) follow.
mxaccess_gateway.proto:
- Extend MxEventFamily with MX_EVENT_FAMILY_ON_ALARM_TRANSITION = 5.
- Extend MxEvent.body oneof with OnAlarmTransitionEvent on_alarm_transition = 24.
- Add OnAlarmTransitionEvent message carrying the full MxAccess alarm
payload (full reference, source object, alarm-type-name, transition
kind, raw severity, original raise timestamp, transition timestamp,
operator user/comment, category, description, current/limit value).
Mapping to OPC UA 0-1000 severity ladder happens server-side in
lmxopcua's MxAccessSeverityMapper (B.1) — gateway preserves the
native MxAccess scale.
- Add AlarmTransitionKind enum (Raise / Acknowledge / Clear / Retrigger).
- Add ActiveAlarmSnapshot + AlarmConditionState for the
ConditionRefresh stream.
- Add public RPCs AcknowledgeAlarm (unary) and QueryActiveAlarms
(server-streaming) on MxAccessGateway service.
- Add AcknowledgeAlarmRequest/Reply + QueryActiveAlarmsRequest.
GatewayContractInfo.GatewayProtocolVersion bumps 2 -> 3. Fixture
manifests (proto-inputs, behavior, parity, golden OpenSessionReply)
and protoset descriptor regenerated.
Tests: round-trip serialization for the new messages with
all-fields-populated and empty-optional-fields cases; oneof
last-write-wins guard between OnDataChange and OnAlarmTransition;
descriptor service-method enumeration includes the two new RPCs.
All 273 existing tests still pass.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Joseph Doherty