MES alarm-status API §5.2 (docs/plans/2026-06-30-mes-alarm-status-api.md,
Phase 1 tasks 2-4). Site `Call` scripts had NO way to read alarm condition
state: the `Alarm` global exists only inside an on-trigger handler and
describes the one alarm that fired, and native mirrored conditions were
reachable only from the Debug View. That gap blocked the CvdReactor
SimpleAlarmStatus/AlarmStatus scripts entirely -- they cannot be written
without it. `Alarms.CurrentAsync()` closes it.
The data was already local: the script runs inside its own Instance Actor's
context, so this is a LOCAL Ask -- the same mechanism attribute reads use, no
cross-cluster hop. A dedicated GetAlarmSnapshotRequest/Response is used rather
than reusing DebugSnapshotRequest, which would materialise every attribute
value on every alarm poll; both are served from the same
BuildAlarmStatesSnapshot(), so the script view and the operator's Debug View
can never disagree.
Deliberate shape decisions:
- NOT scope-prefixed, unlike Attributes. Alarm identity is not a
scope-relative attribute name (computed alarms are keyed by configured
name, native conditions by a source-supplied reference), so prefixing
would hand a composed script a silently truncated list.
- Read-only. Native alarms are a read-only mirror of the source (no
ack-back), so no acknowledge/shelve operation is exposed.
- Placeholder rows are NOT pre-filtered: a caller must be able to tell
"binding configured and quiet" from "binding unknown". The documented
filter is `Active && !IsConfiguredPlaceholder`.
- ScriptAlarm lives in Commons so the runtime accessor and the compile-only
surface project to the SAME type -- a script binding at the design-time
gate binds identically at the site. Condition is the authority for
active/acked/severity, so one filter expression works across computed and
native alarms.
Mirrored on BOTH design-time surfaces. ScriptCompileSurface is covered by the
reflection parity guard (AlarmsAccessor added to its mirror pairs). The Central
UI Test-Run SandboxScriptHost is the third, hand-maintained mirror that the
parity test cannot reach (Central UI does not reference Site Runtime); without
it the design page would false-flag CS1061 on scripts the deploy gate accepts.
It throws a labelled ScriptSandboxException at run time -- there is no central
route to per-instance alarm state, and returning an empty list would read as
"nothing is in alarm", which is worse than an error.
ScriptTrustPolicy needs NO change, and the reason is structural rather than
incidental: the trust boundary is a deny-list over API roots, not an allow-list
of context members. A test pins that no ForbiddenScopes entry prefixes the
Commons script-surface namespace, so a future deny-list entry cannot silently
make ScriptAlarm untouchable.
Tests: 6 accessor cases (Ask contract, full native projection incl. AckTime,
unacked, computed-alarm derivation, placeholder visibility, scope-independence),
2 InstanceActor snapshot cases incl. equality with the Debug View row set, the
full MES script shape compiling against ScriptCompileSurface, 2 trust cases,
and a sandbox diagnose-clean case reading every projected ScriptAlarm field.
#3 — CollisionDetector counted a derived template's IsInherited placeholder
rows as a distinct origin from the parent members the inheritance walk
re-adds, reporting a spurious "Naming collision" for every inherited row and
blocking any attribute/composition add to a derived template. CollectDirectMembers
now skips IsInherited rows on the direct-template and inherited-parent walks;
it keeps them for the composed-module walk, where placeholders are the sole
representation of a derived module's inherited members (that walk does not
climb the composed template's parent chain).
#7 — SandboxAttributeAccessor (Central UI Test-Run host) omitted
WriteBatchAndWaitAsync / WaitAsync / WaitForAsync, so the editor false-flagged
valid instance scripts with CS1061 even though `template validate` and the
deploy gate accept them. Added the five overloads mirroring the runtime
AttributeAccessor; they throw a labelled ScriptSandboxException if run in
Test Run (the central sandbox has no device-batch / event-waiter transport).
Tests: +3 CollisionDetector unit + 1 end-to-end TemplateService (derived add
now succeeds); +2 ScriptAnalysisService diagnose-clean. Each new test verified
to fail without its fix with the exact user-facing symptom. Full suites green
(TemplateEngine.Tests 438, CentralUI.Tests 866).
Docs: Component-TemplateEngine.md (inherited-placeholder collision rule),
Component-ScriptAnalysis.md (third sandbox surface + its compile-clean guard),
known-issues tracker #3/#7 marked resolved and the minor note promoted to #8.
Resolves InboundAPI-026/027/028/029 (+ newly-surfaced -030).
- 026: authorize the scoped Database helper in the design doc; SQL-injection
protection is parameter binding (values never concatenated); allow writes via
ExecuteAsync; drop the false 'read-only' claim. Named connections only.
- 027: async ADO.NET end-to-end (no .GetAwaiter().GetResult()); honour the method
deadline token on ExecuteScalarAsync/ExecuteReaderAsync/ExecuteNonQueryAsync +
a CommandTimeout backstop derived from the method timeout.
- 028: negative-path tests (null-gateway, deadline cancellation, parameterization)
+ e2e Database + WaitForAttribute cases through the real endpoint.
- 029: WaitForAttribute is bounded by its WAIT timeout (per-wait CTS + client-abort
+ explicit token), NOT the method deadline (spec §6) — a long wait may outlive the
method timeout; WithRequestAborted threads the raw client-abort token separately.
- 030: Central UI compile-surface mirrors (InboundScriptHost / SandboxInboundScriptHost)
gained the Database member (drifted since the runtime helper was added) so the
authorized async API type-checks at the design-time gate.
Add WaitForAttribute(attributeName, targetValue, timeout, cancellationToken)
to InboundScriptHost.RouteTarget and SandboxInboundScriptHost.RouteTarget,
mirroring the shipped runtime signature in RouteHelper. Eliminates the false
CS error the editor raised against valid Route.To("X").WaitForAttribute(...)
calls in inbound API method scripts. Test asserts the call diagnoses clean
under ScriptKind.InboundApi.
Joseph Doherty