F1: the driver's outage BadNoCommunication carried the last Good sample's
source timestamp. The recorder historizes SourceTimestampUtc ??
ServerTimestampUtc, so the Bad landed on the Good row's (TagId,
SourceTimeUtc) key and the insert-if-absent historian dropped it - no
outage marker until the host's watchdog marker ~95 s in, none at all for
a short blip. Now stamped with the detection time (source + server), as
the host's comms-loss fan does.
F2: after a same-session recovery the SDK delivered a missed notification
seconds late with an older source time and the node regressed. A
notification older than the newest Good upstream source time for its ref
(notification or recovery read) is dropped and counted
(stale_notification_dropped); equal timestamps pass; the outage Bad never
moves the comparison; a re-initialise resets it.
A bad keep-alive now degrades health (LastSuccessfulRead preserved) and,
once per outage, publishes BadNoCommunication (value retained) for every
subscribed ref plus a quality-only annotation on subscribed alarm
conditions. Good keep-alives and data/event notifications advance
LastSuccessfulRead, so an idle-but-alive subscription never looks dead
to the #527 watchdog. A keep-alive that recovers on the same session
re-reads the Bad refs and republishes them Good; a session that does not
come back is recovered by the watchdog's ShutdownAsync + InitializeAsync
+ re-subscribe.
Deletes the SessionReconnectHandler wiring (it retried forever in SDK
1.5.378, cloned subscriptions the driver never re-tracked and kept health
Healthy), OnReconnectComplete, TryRearmReconnect and the reconnect_*
counters (new keepalive_recovered). Teardown of a lost session skips
wire deletes and bounds CloseSession. SDK warnings reach the driver log.
Wire test reworked: restart => Bad, then watchdog-style reinit => Good.
Adds <summary>/<param>/<returns>/<inheritdoc> where missing and removes
project bookkeeping IDs (task/tracking refs) from shipped code comments,
so the docs read cleanly and CommentChecker is quiet except for known
false positives (PLC/protocol terms, event/IEqualityComparer inheritdoc).
Doc/comment-only; no logic changed; solution builds clean.
Adds <summary>, <param>, <typeparam>, and <inheritdoc/> tags to public
members surfaced by commentchecker — resolves 5,847 of 5,869 issues
(99.6%) across three /fixdocs passes.
OtOpcUaTelemetry (Commons/Observability) centralizes the project's Meter
+ ActivitySource so all instrumentation points emit through a single
named surface. Counters cover the hot paths:
otopcua.deploy.applied (outcome=ack|reject)
otopcua.deploy.apply.duration (s, histogram)
otopcua.driver.lifecycle (event=spawn|spawn_stub|stop|fault)
otopcua.virtualtag.eval (outcome=ok|fail|skip)
otopcua.scriptedalarm.transition (state=activated|acknowledged|cleared)
otopcua.opcua.sink.write (kind=value|alarm|rebuild)
otopcua.redundancy.service_level_change (level=byte)
Plus two ActivitySource spans:
otopcua.deploy.apply wraps DriverHostActor.ApplyAndAck
otopcua.opcua.address_space_rebuild wraps OpcUaPublishActor.HandleRebuild
Instruments are no-op until a listener attaches, so tests + dev hosts
pay nothing for unread telemetry.
Host Program.cs gains AddOtOpcUaObservability() (binds the OtOpcUa Meter
+ ActivitySource to OpenTelemetry, attaches a Prometheus exporter) and
MapOtOpcUaMetrics() (mounts /metrics scrape endpoint). Driver-side
internals + ASP.NET request metrics deliberately stay off — the scrape
payload is scoped to OtOpcUa signals only.
Tests use MeterListener + ActivityListener to verify
VirtualTagActor.eval, OpcUaPublishActor.AttributeValueUpdate, and
RebuildAddressSpace actually emit on the central instruments. Runtime
suite is 72 / 72 green (+3).
Closes#105. Path A (F13b/c/d) complete; next batch options: #85 UNS
folder hierarchy in SDK, or F8b/F9b production engine bindings.
Joseph Doherty