Commit Graph

4 Commits

Author SHA1 Message Date
Joseph Doherty e7fbe97759 fix(historian): gate historization capture on the Primary, quarantine a poison tag (#537, #538)
Both defects were found by #491's live gate against a real HistorianGateway and filed rather than
fixed at the time, because each one's fix is a design decision rather than a patch.

#537 — both nodes of a redundant pair captured every value, so the historian received duplicate
live samples for every historized tag (measured: the gateway's write counter advanced twice per
value and halved when one central was stopped).

The recorder now reads a capture gate per value, fed from the new
PrimaryGatePolicy.ShouldRecordHistorizedValues through IHistorizationRoleView — a third verdict on
the same RedundancyRoleView object, registered unconditionally on driver nodes rather than
alongside the alarm section's IRedundancyRoleView (which only exists when that section is enabled;
piggybacking is the #511 registration accident).

Two things are deliberate and easy to get backwards:

  * It gates the CAPTURE, not the drain — the opposite of the alarm sink. That queue is in LocalDb
    and replicates, so the Secondary already holds the Primary's rows. The historization outbox is
    a node-local FasterLog replicating to nobody, so a drain-only gate would leave the standby
    appending forever to a queue no one empties: unbounded disk, then a flood of stale duplicates
    the moment it is promoted. Entries a node already captured are still drained by that node.

  * The peer it stands down for must RECORD THE SAME REFS, not merely hold the same rows — a
    Primary in this node's own per-cluster mesh. A node carrying no cluster-scoped role cannot
    establish that and never stands down: under a fleet-wide election the elected Primary is
    usually running a different cluster's configuration, and deferring to it would end this
    cluster's historization silently, with the drain reporting success on an empty outbox forever.
    That is the scope mismatch that once suspended the alarm drain on every node of the rig.

An unknown role captures, matching the alarm drain — a duplicate sample is recoverable, a hole in
the trend is not.

#538 — the drain writes every per-tag group and then acks all-or-nothing (deliberate: RemoveAsync
truncates THROUGH an id, so partial acking could drop older unwritten entries). One permanently
failing tag therefore pinned the FIFO head while every healthy tag in the batch was re-submitted
to the historian on every pass, indefinitely — duplicate samples and an outbox that never
truncated, observed live at 8.3 MB from a single unprovisionable tag.

The drain now tracks consecutive failures per historian tag and abandons that tag's entries once
it exceeds MaxWriteAttempts (new, default 5), so the head advances. The counter only advances on a
pass where some OTHER tag wrote successfully: that is what separates "this tag is poison" from
"the backend is down". A count-only quarantine looks identical on the poison-tag case and silently
discards the whole backlog during an ordinary gateway restart, turning a duplicate-samples bug
into a lost-history one. Abandonment is also deferred until every failing tag is over budget, so
nothing is discarded on a pass that could not have advanced the head anyway. Each abandonment logs
a Warning naming the tag; the total rides RecorderStatus.AbandonedEntries.

Capacity also gains a non-zero default (500,000 entries) as the disk backstop for the one case the
quarantine deliberately cannot resolve — a historian refusing every write, where retaining is
correct. Set 0 to restore unbounded retention.

Every new test was falsified by reverting the production change it guards, and each one reddens
alone:

  * drop the backend-reachable evidence -> only A_backend_that_fails_every_tag_abandons_nothing
  * never abandon -> only A_permanently_failing_tag_is_abandoned_so_healthy_tags_stop_being_rewritten
  * latch the capture gate at construction -> only The_capture_gate_is_re_read_per_value...
  * treat any Primary as a scope peer -> only the two scope-mismatch cases

Full suite green. (Four OpcUaClient.Browser failures during the run were the opc-plc fixture being
down on the shared Docker host; brought it back up and they pass.)

Claude-Session: https://claude.ai/code/session_015p7wGqy3YpZNCpDzTpGMKo
2026-08-04 12:12:16 -04:00
Joseph Doherty 7f2108dcf2 feat(mqtt): Sparkplug primary-host STATE publishing, Primary-gated (#511)
`ActAsPrimaryHost` was accepted by config and by the AdminUI form and did nothing but
log a warning. It now delivers the whole three-part contract or none of it: a retained
`ONLINE` on `spBv1.0/STATE/{hostId}`, a matching retained `OFFLINE` armed as the MQTT
Last Will, and an explicit `OFFLINE` on a clean stand-down.

**The claim is a dedicated connection, not a message.** A Will can only be registered in
the CONNECT packet — it cannot be added to a live session, changed, or withdrawn. So a
claim that is acquired and released at runtime cannot ride the long-lived ingest session.
`SparkplugPrimaryHost` opens its own connection (client id `{clientId}-spbhost`, forced
clean-session) when the node gains Primary and closes it when the node loses Primary; the
connection's lifetime *is* the claim, so every leg follows from its lifecycle. Ingest is
untouched by a role change — no dropped subscriptions, no lost birth cache, no data gap at
the Secondary->Primary transition.

**Primary-gated** (owner decision, recorded on the issue). Both pair nodes subscribe
independently, so an ungated claim means both claim the same host id — and the sharp
failure is not the two fighting over the retained STATE, it is that the SECONDARY's death
fires its Will and publishes OFFLINE while the Primary is healthy, stopping every edge node
in the group. Registering the Will only on whichever node is Primary at connect time fails
the other way: a node that later gains Primary would publish ONLINE with no Will behind it.

New seam: `IDriverPrimaryRoleSource` (`Core.Abstractions`) carrying the *data-plane* verdict
(`PrimaryGatePolicy.ShouldServiceAsPrimary`), not the alarm-drain verdict — an unknown role
with a driver peer present must deny. Registered unconditionally by `AddOtOpcUaRuntime`,
deliberately NOT alongside `IRedundancyRoleView`, which `AddAlarmHistorian` registers only
when that section is enabled: piggybacking would leave a pair with no alarm historian
falling back to "claim unconditionally". Polled on a 1s timer rather than evented — a
process singleton raising events at per-instance drivers outlives every driver it holds.

Accepted trade: a brief edge-visible OFFLINE window during failover. That is a genuine
state transition, not a glitch to hide.

Live-gated 5/5 against the Mosquitto fixture, including the Will leg — `AbandonForTests`
drops the socket with no DISCONNECT, because a clean disconnect makes the broker discard
the Will by protocol rule, so a test driven through `StopAsync` would observe the
stand-down OFFLINE and pass against an implementation that never armed a Will. Falsified:
removing the Will turns that leg and only that leg red.

Also corrects two stale claims found en route: the AdminUI form still said MQTT tags are
read-only (#508 shipped), and the driver doc still said nothing consumes `IRediscoverable`.

Claude-Session: https://claude.ai/code/session_015p7wGqy3YpZNCpDzTpGMKo
2026-07-31 07:17:17 -04:00
Joseph Doherty f9f1b8fcee fix(localdb): phase-2 live gate — 4 production defects found and fixed
Gate record: docs/plans/2026-07-20-localdb-phase2-live-gate.md.
Checks 1, 2, 5, 6 pass. Checks 3 and 4 are NOT satisfied — the defect they
were meant to confirm turned out to be the opposite of what the plan assumed.

Three defects crash-looped every driver node before check 1 could even run:

1. An empty ServerHistorian:ApiKey kills the host. ServerHistorianOptions-
   Validator exists to turn exactly that class of failure into a named
   OptionsValidationException, but its documented fail tier explicitly excluded
   ApiKey on the reasoning that a keyless client "degrades — the gateway rejects
   calls". It does not: the client validates its own options at construction, so
   the process dies during Akka startup and never makes a call.

2. UseTls disagreeing with the endpoint scheme kills the host too, in both
   directions (both messages confirmed in the shipped client assembly). Moving an
   endpoint from https to http without clearing UseTls is an ordinary migration
   slip.

3. Plaintext h2c was UNREACHABLE. HistorianGatewayClientAdapter forwarded the
   TLS-only options unconditionally, and AllowUntrustedServerCertificate defaults
   to false, so it always sent RequireCertificateValidation=true — which the
   client rejects outright when UseTls=false. Every http:// deployment crashed,
   though the scheme is documented as the supported way to select h2c, and the
   only workaround was to assert a certificate posture for a connection that has
   no certificate.

The fourth was the blocker, and it is Phase 2's own:

4. The drain gate deferred to a Primary that cannot deliver. Redundancy roles are
   elected CLUSTER-WIDE; the alarm queue is PAIR-LOCAL. On the rig the elected
   driver Primary is central-1 — it carries the driver Akka role, replicates
   nobody's LocalDb and does not even run the alarm historian — so every driver
   node logged "Historian drain suspended", including the two site-b nodes that
   have no peer at all. Nothing drained anywhere, where before Phase 2 it drained
   fine. The cost is not a duplicate; it is the buffer growing to the capacity
   wall and evicting the audit trail it exists to protect.

   Fixed in three layers: a separate ShouldDrainAlarmHistory policy (unknown role
   drains; the two gates now deliberately disagree, and a test pins that); peer-
   host matching in DriverHostActor so a node stands down only for a Primary
   holding its rows; and AddAlarmHistorian short-circuiting the gate when
   replication is unconfigured — testing BOTH Replication:PeerAddress and
   SyncListenPort, since only the dialing half sets the former while both halves
   share the queue.

   Every one of these follows from the asymmetry: a false allow costs a duplicate
   row, which at-least-once delivery already accepts and payload-hash ids
   collapse; a false deny loses data silently.

A third vacuous test, caught by the same delete-the-guard discipline: the
role-view tests stayed green with the guard removed, because AwaitAssert polls
until an assertion passes and the assertion was "reads open" — which is the
SEEDED value, satisfied at the first poll before the actor processed anything.
They now assert the sequence of published values through a recording view; the
control then goes red for exactly the cases that matter.

Migration evidence: 11 legacy rows across two deliberately overlapping files
converged to exactly 9 identical rows on both nodes, proving D-6's payload-hash
identity on real nodes rather than in a fixture.

Open design fork, recorded in the gate doc rather than decided here: a pair
cannot currently identify its own Primary, so both halves drain. Safe in every
topology — nothing loses data — but the gate's de-duplication benefit is
unrealised until roles are scoped per pair.

Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
2026-07-21 06:13:01 -04:00
Joseph Doherty 71379816e7 feat(localdb): alarm S&F on LocalDb with primary-gated drain (cutover)
Moves the alarm store-and-forward buffer out of its own alarm-historian.db
and into the node's consolidated LocalDb, where it replicates to the
redundant pair peer. A node that dies holding undelivered alarm history no
longer takes it to the grave.

Tasks 2 and 3 land together, as the plan anticipated. They are not separable:
the gate is a constructor argument of the rewritten sink, and a commit that
replicated the queue without gating the drain would be a commit in which both
nodes of a pair deliver every alarm event, continuously.

That drain gate is the load-bearing part of the change, and the recon
explains why it is new work rather than a refinement. Exactly-once delivery
across a pair is enforced today on the ENQUEUE side, by
HistorianAdapterActor: only the Primary enqueues, so the Secondary's queue is
empty and its ungated drain has nothing to send. Replicating the table
destroys that invariant.

The gate is a Func<bool> the caller supplies, because the drain runs on a
timer the sink owns rather than on a mailbox, and Core.AlarmHistorian cannot
reference PrimaryGatePolicy in Runtime. Runtime supplies it via a new
IRedundancyRoleView singleton that DriverHostActor publishes its Primary-gate
verdict to -- the same verdict the inbound-write and native-ack gates use, so
there is no second notion of am-I-the-Primary to drift.

Two failure modes are deliberately closed:

- The view is seeded OPEN, matching the policy's own answer for an unknown
  role with no driver peer. A deployment that runs no redundancy never
  publishes to it, and defaulting closed would silently stop its alarm
  history forever.

- A gate that throws is read as not-now, never as permission, and a closed
  gate reports the new HistorianDrainState.NotPrimary rather than Idle. A
  Secondary's rising queue is supposed to look different from a stalled
  drain, and if BOTH nodes report NotPrimary the pair is misconfigured and
  says so instead of quietly filling toward the capacity ceiling.

Row ids are a hash of the payload rather than fresh GUIDs. Both adapters
accept the same fanned transition in the window before the first redundancy
snapshot arrives, and under last-writer-wins an equal key converges those two
accepts into one row instead of duplicating them.

Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
2026-07-21 04:13:00 -04:00