MES alarm-status API §6.4 (docs/plans/2026-06-30-mes-alarm-status-api.md,
Phase 1 task 1). MES needs a real AckDT for a triggered alarm, and the mirror
carried acked-vs-unacked but never WHEN. AckTime now rides the whole path:
DCL transition -> AlarmStateChanged -> gRPC AlarmStateUpdate -> site SQLite.
Stamping rule, identical on both protocols: non-null ONLY while the condition
is active AND acknowledged. That single predicate yields all three required
behaviours -- null while unacked, cleared on re-raise (a re-raise arrives
unacknowledged), and no phantom ack on a return-to-normal. The last one is
load-bearing for MxGateway, which maps INACTIVE to Acknowledged = true; without
the active check every clear would claim an ack the system never observed.
Provenance is honest, never fabricated:
- OPC UA A&C supplies a TRUE ack instant, so we now select it:
AcknowledgeableConditionType/AckedState/TransitionTime at SelectClause
index 18, APPENDED so the positional reads at 0-17 keep their meaning.
Servers that omit the field fall back to the event's own Time.
- MxAccess Gateway supplies none, so the ack transition's own timestamp is
used -- accurate to when the system SAW the ack. An ACTIVE_ACKED
re-subscribe snapshot restores one from LastTransitionTimestamp rather
than dropping it.
The decision lives in pure mappers (Opc/Mx AlarmMapper.DeriveAckTime), so it is
unit-tested with no live server or gateway.
Additive-only throughout: init-only property on AlarmStateChanged, trailing
optional positional on NativeAlarmTransition (all 14-arg call sites untouched),
proto field 24 (never reusing a number) regenerated via docker/regen-proto.sh
sitestream with the csproj diff verified empty.
Persistence rides native_alarm_state's existing metadata_json blob rather than
a new column -- deliberately. That table is RegisterReplicated in
SiteLocalDbSetup and LocalDb builds its CDC triggers from the column list at
registration time, so an additive JSON property changes no schema, no triggers
and no replication contract; metadata_json is exactly the extension point UA4
introduced for this. Rows written before the field deserialize it as null.
Tests: 4 OPC UA + 6 MxGateway mapper cases, 3 NativeAlarmActor (emit,
failover rehydrate, pre-AckTime row), 1 proto round-trip incl. the null case,
4 Commons additive/back-compat. The OPC UA SelectClause count lock-in moves
18 -> 19 with an index-18 assertion -- intended, the clause is appended, which
is precisely what that guard exists to make visible.
Code review of a1abbff7 found two edge cases: a discovery/advertised URL with no
explicit port emitted a malformed ':-1' (opc.tcp has no Uri default port), and an
IPv6 literal host could lose/double its brackets. Omit the port when neither URL
carries one; bracket an IPv6 host only when missing. +4 tests (12 total).
An OPC UA server advertises its base address from its own config, not the route
the client took — commonly a 0.0.0.0 wildcard bind or an internal container/NAT
hostname. The OPC Foundation session dials EndpointDescription.EndpointUrl
verbatim, so a 0.0.0.0 advertisement resolved to the client's own loopback and
the connect failed. RealOpcUaClient now swaps the advertised authority for the
reachable host/port (ConnectAsync + VerifyEndpointAsync), preserving scheme+path;
no-op when already reachable. Surfaced live-gating OtOpcUa v3 (#14).
A stored ns=<index> reference is only meaningful against one server's namespace
table. A server that adds, removes or reorders a namespace silently re-points
every binding: best case BadNodeIdUnknown, worst case the index now names a
different namespace holding a colliding identifier and the binding resolves to
the wrong node with Good quality. Nothing could detect that, because ScadaBridge
stored no namespace URI anywhere.
OtOpcUa v3.0 makes this concrete: v2's sole custom namespace and v3's raw
namespace both sit at index 2, so v2-era bindings resolve against v3 without
error while meaning something else entirely.
Adds OpcUaNodeReference as the single translation seam between stored references
and the wire. Resolve() accepts both ns=<index>;s=<id> (existing bindings, which
keep working unchanged) and the durable nsu=<uri>;s=<id>, mapping the URI to the
live index at use time; it is wired into every parse site — subscribe, read,
write, alarm-subscribe and browse. An unpublished URI now throws naming the URI
rather than binding to whatever occupies that index, and a svr= reference to
another server is rejected instead of being resolved against the wrong address
space.
The browser emits ToDurable(), so what the picker shows is what gets stored and
newly-authored bindings are index-proof from the start. That also closes a
round-trip gap: browse previously emitted ExpandedNodeId.ToString(), which for a
URI- or server-index-carrying reference produced a string NodeId.Parse could not
read back — the same method already resolved it correctly 57 lines later.
Bindings stored before this change keep their ns= form and keep working; they are
only as durable as the server's namespace order. Re-authoring against the picker
is what makes them durable, and that re-bind still needs a live v3 rig.
Refs: Gitea #14
OPC UA (RealOpcUaClient):
- Append 5 new SelectClauses at indices 13–17 (never renumber 0–12):
- 13: AlarmConditionType/ActiveState/TransitionTime → OriginalRaiseTime
- 14–17: LimitAlarmType HighHighLimit/HighLimit/LowLimit/LowLowLimit → LimitValue
- New OpcUaAlarmMapper.PickLimitValue helper: first non-null in HiHi→Hi→Lo→LoLo
priority order, InvariantCulture-formatted; empty string for non-limit alarm types.
- HandleAlarmEvent reads new indices with fields.Count > N guards; hard minimum (6)
unchanged so base ConditionType events still process without the limit fields.
- Document unavailable-by-protocol fields (Category, Description, OperatorUser,
CurrentValue) inline in BuildAlarmEventFilter and HandleAlarmEvent.
MxGateway (MxGatewayAlarmMapper):
- MapTransition: CurrentValue and LimitValue now populated via MxValueToString
(uses MxValueExtensions.ToClrValue + InvariantCulture) from OnAlarmTransitionEvent
proto fields current_value/limit_value.
- MapSnapshot: same — populated from ActiveAlarmSnapshot.current_value/limit_value.
- MxValueToString helper (internal): null-safe MxValue → string conversion.
Tests (17 new, 40 total pass):
- OpcUaAlarmMapperTests: PickLimitValue priority, InvariantCulture, all-null case.
- MxGatewayAlarmMapperTests: CurrentValue/LimitValue populate from double/string
MxValue; absent fields yield empty strings.
- RealOpcUaClientAlarmFilterTests: index alignment assertions (count=18, per-index
TypeDefinitionId+BrowsePath), regression guard on existing indices 0–12.
conditionFilter was plumbed end-to-end but applied nowhere — a filtered source
silently mirrored all conditions. Define the filter as a comma-separated,
case-insensitive list of condition type names (blank = all); enforce it
authoritatively client-side in DataConnectionActor routing (uniform across OPC UA
+ MxGateway) and, for OPC UA, additionally build a server-side EventFilter
WhereClause as a bandwidth optimization.
Adds IAlarmSubscribableConnection to MxGatewayDataConnection (shared session-less
feed, ref-counted), IMxGatewayClient.RunAlarmStreamAsync over the package
StreamAlarmsAsync with internal reconnect, and MxGatewayAlarmMapper
(AlarmFeedMessage/OnAlarmTransitionEvent -> NativeAlarmTransition). Behavior
verified against a live gateway in Task 28; mapper unit-tested.
Implements IDataConnection + IBrowsableDataConnection over the IMxGatewayClient
seam: connect/disconnect with once-only Disconnected guard + background event
loop, subscribe/unsubscribe with tag routing, read/write batch with per-tag
error classification, WriteBatchAndWait, and Galaxy browse mapping. Covers plan
Tasks 6-10. Full unit coverage via FakeMxGatewayClient (12 tests).
Joseph Doherty