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docs(alarms): document the Alarms accessor + AckTime, tick MES plan Phase 1

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Design doc and code travel together (CLAUDE.md editing rules), so this records
what the two preceding commits shipped and, more usefully, WHY the non-obvious
choices were made -- the parts a future reader would otherwise re-litigate:

  - Component-SiteRuntime.md: the Alarms.CurrentAsync() runtime API entry (why
    it is not scope-prefixed, why it is read-only, why placeholder rows are
    included), the full ScriptAlarm shape, AckTime on the enriched
    AlarmStateChanged, proto field 24, and the metadata_json-vs-new-column
    persistence rationale (native_alarm_state is RegisterReplicated; LocalDb
    builds its CDC triggers from the column list at registration time).
  - Component-DataConnectionLayer.md already carried the AckTime section in the
    first commit; this adds the SiteRuntime/ScriptAnalysis/InboundAPI halves.
  - Component-ScriptAnalysis.md: accessors returning domain types return the
    SAME type on both surfaces, and the trust-model note that a deny-list needs
    no entry for a new globals member -- only that its return type resolves in
    a permitted namespace.
  - Component-InboundAPI.md records the NEGATIVE decision: there is
    deliberately no Route.To(...).GetAlarms(...) verb. Alarm state is
    per-instance and lives on the site's Instance Actor, so the read goes
    through a routed site script and the filtering happens where the data is;
    central stays a thin router.
  - CLAUDE.md native-alarm bullet gains the enrichment + accessor summary.
  - The plan's §7 Phase 1 rows are ticked with 2026-08-01 and annotated with
    what was actually built (incl. the two choices that differ from the plan's
    "or" options: a dedicated snapshot message rather than DebugSnapshotRequest,
    and the extra SandboxScriptHost mirror the plan did not list). Phases 2-4
    stay open -- they are deployed config and need a live rig.
This commit is contained in:
Joseph Doherty
2026-08-01 13:12:46 -04:00
parent d0af884760
commit 3c9b101dfc
5 changed files with 50 additions and 18 deletions
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docs/requirements/Component-SiteRuntime.md
+14 -2
View File
@@ -350,6 +350,7 @@ The Instance Actor owns native-alarm setup alongside its computed Script and Ala
- **Columns**: `condition_json` (the serialized `AlarmConditionState`), `metadata_json` (display metadata — type/category/message/current+limit, UA4), and `last_transition_at` (the accepted `TransitionTime`).
- **Operations**: `Upsert` (on accepted transition), `Delete` (on condition drop-out), `Get` (PreStart rehydrate, scoped to instance + source), and `ClearForInstance` (redeploy/undeploy reset).
- **Display metadata persistence (UA4)**: persisted rows include the condition's display metadata, so **rehydrated conditions render fully** (type / category / message / current + limit values) before the first fresh source snapshot arrives; a pre-UA4 row with no metadata rehydrates with empty display fields (unchanged behavior).
- **Ack timestamp persistence**: the condition's `AckTime` rides the same `metadata_json` blob, so an acknowledged alarm keeps its ack instant across restart/failover rather than reappearing as if it had never been acknowledged. It is deliberately **not** a new physical column: `native_alarm_state` is `RegisterReplicated` in `SiteLocalDbSetup`, and LocalDb builds that table's CDC triggers from the column list at registration time — an additive JSON property changes no schema, no triggers and no replication contract, and `metadata_json` is exactly the extension point UA4 introduced for this. A row written before the field existed deserializes it as `null` ("ack time unknown"), which is the correct fallback. See `docs/plans/2026-06-30-mes-alarm-status-api.md` §6.4.
- **Coalesced writes (P4)**: per-transition upserts are coalesced (latest-per-source-reference) and flushed on a short single-shot timer rather than one SQLite write per transition, so an alarm storm collapses to one batched write; a pending upsert is dropped if the condition is deleted before the flush (no resurrection). Durability window is at most one flush interval on crash, reconciled by the next re-subscribe snapshot.
- This is a **peer SQLite store** to the existing deployed-configuration, store-and-forward, operation-tracking, and `AuditLog` stores. Unlike computed alarm state, native mirror state is intentionally persisted so it survives failover.
@@ -365,8 +366,9 @@ The `AlarmStateChanged` message published by both Alarm Actors and Native Alarm
- **Computed-alarm projection**: computed alarms are surfaced as **auto-acknowledged** with `Severity = Priority`, so a single enriched shape carries both computed and native alarms onto the stream and into the DebugView snapshot.
- **`NativeSourceCanonicalName`** (`string?`): the canonical name of the native alarm source binding a native condition belongs to (e.g. `Motor1.NativeAlarms`). `null` for computed alarms. Stamped by the `NativeAlarmActor` on every emitted event; also carried on idle-binding placeholder rows emitted by the Instance Actor.
- **`IsConfiguredPlaceholder`** (`bool`): `true` for a synthetic row emitted by the Instance Actor to represent a configured native source binding that currently has no live conditions. These rows are never persisted or forwarded as operational alarms — they exist solely so the Debug View can render every configured binding as a tree node. `false` on all other rows.
- **`AckTime`** (`DateTimeOffset?`): the instant the condition was acknowledged; `null` while unacknowledged, `null` on computed alarms (auto-acked but with no operator ack event), and cleared on re-raise. Stamped by the DCL adapter — the source's own ack instant where the protocol supplies one (OPC UA A&C), the DCL's observation time of the ack transition where it does not (MxAccess Gateway) — and carried verbatim by the `NativeAlarmActor`, which never invents or suppresses one. See [Component-DataConnectionLayer.md](Component-DataConnectionLayer.md) → *Ack Timestamp*.
Both fields are **additive-only** (init-only with defaults: `null` / `false`) and are mirrored additively on the gRPC `AlarmStateUpdate` proto as fields 22 (`native_source_canonical_name`, `string`) and 23 (`is_configured_placeholder`, `bool`). `StreamRelayActor` and `SiteStreamGrpcClient` pack/unpack these fields without touching existing fields, preserving backward compatibility across version-skew boundaries.
These fields are **additive-only** (init-only with defaults: `null` / `false`) and are mirrored additively on the gRPC `AlarmStateUpdate` proto as fields 22 (`native_source_canonical_name`, `string`), 23 (`is_configured_placeholder`, `bool`) and 24 (`ack_time`, `google.protobuf.Timestamp`, absent ⇒ `null`). `StreamRelayActor` and `SiteStreamGrpcClient` pack/unpack these fields without touching existing fields, preserving backward compatibility across version-skew boundaries.
The enriched message flows Instance Actor → site-wide Akka stream → `SiteStreamManager` → `SiteStreamGrpcServer` and is streamed to central as the gRPC `AlarmStateUpdate` event (see [Component-Communication.md](Component-Communication.md)).
@@ -437,6 +439,16 @@ Available to all Script Execution Actors and Alarm Execution Actors:
### Operation Tracking
- `Tracking.Status("trackedOperationId")` — Returns a status record (status, retry count, last error, key timestamps) for any tracked operation: a cached external system call, a cached database write, or a notification. For cached calls and writes the answer is always site-local and authoritative — the site owns the operation tracking table. (`Notify.Status(...)` is a thin alias scoped to the notification domain.)
### Alarm State (read-only)
- `Alarms.CurrentAsync()` — Returns a snapshot of the instance's **current** alarm conditions as `IReadOnlyList<ScriptAlarm>` (`Commons.Types.Scripts`), covering computed alarms and mirrored native (OPC UA A&C / MxAccess Gateway) conditions alike. Served by a **local Ask** (`GetAlarmSnapshotRequest`/`GetAlarmSnapshotResponse`) to the script's own Instance Actor — the same mechanism attribute reads use, never a cross-cluster hop.
- Available to **every** script, unlike the `Alarm` global, which exists only inside an on-trigger handler and describes the single alarm that fired. This accessor is what lets an inbound-API-routed `Call` script answer "what is in alarm on this machine right now?"; before it, native mirrored conditions were reachable only from the Debug View.
- **Read-only by design** — native alarms are a read-only mirror of the source (no ack-back), so the accessor exposes no acknowledge/shelve operation.
- **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 every scope sees the same list rather than a silently truncated one.
- The snapshot is built by the same `BuildAlarmStatesSnapshot()` the Debug View uses, so it **includes placeholder rows** for configured-but-quiet native source bindings (`IsConfiguredPlaceholder`). Callers enumerating real alarms filter on `Active && !IsConfiguredPlaceholder`.
- `ScriptAlarm` is a flat projection of the retained `AlarmStateChanged`: `Name`, `SourceReference`, `NativeSourceCanonicalName`, `Active`, `Acknowledged`, `Confirmed?`, `Shelved` (all shelve sub-states collapse to one boolean), `Suppressed`, `Severity` (0–1000), `Kind`, `Message`, `AlarmTypeName`, `Category`, `OperatorUser`, `OperatorComment`, `OriginalRaiseTime?`, `Timestamp`, `AckTime?`, `CurrentValue`, `LimitValue`, `IsConfiguredPlaceholder`. The `Condition` is the authority for active/acked/severity, so computed and native alarms read identically from one filter expression.
- The type lives in Commons so the runtime accessor and the Script Analysis compile-only surface (`ScriptCompileSurface.CompileAlarmsAccessor`) project to the **same** type — a script binding at the design-time gate binds identically at the site. Parity is pinned by `CompileSurfaceParityTests`.
- Design record: `docs/plans/2026-06-30-mes-alarm-status-api.md` §5.2.
### Parameter Access
- `Parameters["key"]` — Raw dictionary access (returns `object?`, requires manual casting).
- `Parameters.Get<T>("key")` — Typed access with descriptive error messages. Throws `ScriptParameterException` if parameter is missing, null, or cannot be converted to `T`.
@@ -456,7 +468,7 @@ Available to all Script Execution Actors and Alarm Execution Actors:
Scripts execute **in-process** with constrained access. The following restrictions are enforced at compilation and runtime:
- **Allowed**: Access to the Script Runtime API (GetAttribute, SetAttribute, CallScript, CallShared, ExternalSystem, Notify, Database, Tracking), standard C# language features, basic .NET types (collections, string manipulation, math, date/time). `System.Diagnostics.Stopwatch`, `Debug`, and `Activity` are permitted.
- **Allowed**: Access to the Script Runtime API (GetAttribute, SetAttribute, CallScript, CallShared, ExternalSystem, Notify, Database, Tracking, Alarms), standard C# language features, basic .NET types (collections, string manipulation, math, date/time). `System.Diagnostics.Stopwatch`, `Debug`, and `Activity` are permitted.
- **Forbidden**: File system access (`System.IO`), process spawning (`System.Diagnostics.Process`), threading (`System.Threading` — except `Tasks`, `CancellationToken`, and `CancellationTokenSource`), reflection (`System.Reflection`), all raw network access (`System.Net` — must use `ExternalSystem.Call`), native interop (`System.Runtime.InteropServices`, `Microsoft.Win32`), assembly loading, unsafe code, `dynamic`, `Activator`.
- **Execution timeout**: Configurable per-script maximum execution time. Exceeding the timeout cancels the script **cooperatively** (S2/UA5): a script blocked in synchronous I/O or a tight CPU loop does not observe cancellation and continues to occupy its dedicated script-execution thread. A **watchdog logs the script by name** once its thread has not returned within a grace period after the timeout, and the script-execution scheduler's **queue depth / busy-thread / oldest-busy-age gauges** are reported through Health Monitoring so a saturated or stuck scheduler is visible.
- **Memory**: Scripts share the host process memory. No per-script memory limit, but the execution timeout prevents runaway allocations.