Driver.Mqtt.Contracts-004/-005/-006/-007.
-004: retainSeed was the last behavioural key read leniently, so "retainSeed":"false"
— what a CSV import produces — silently became the default TRUE, the INVERSE of the
authored intent. Both mappers now read it through TryReadBoolStrict (the qos
absent/valid/present-but-invalid split) and DescribeRejection names it. The authoring
side needed no hand-mirrored rule: MqttTagConfigModel.Validate already consults this
same parse through TagConfigParseGate, so the save is blocked with the inspector's
wording — pinned by a new AdminUI parity theory pair.
-005: the seven [Range] attributes on MqttDriverOptions/MqttPlainOptions never ran —
the options are bound by JsonSerializer, and nothing in the four MQTT projects calls
Validator.TryValidateObject. Two of them CONTRADICTED the real authority (KeepAlive's
[Range(1,…)] forbade the zero Normalize admits as legal MQTT; MaxPayloadBytes' forbade
the non-positive value its own remarks document as falling back to 1 MiB), so wiring
them up would have broken deliberate behaviour. Deleted, with each property naming
where its bound actually lives. The one escape they papered over is closed: an
out-of-range defaultQos rode into the SUBSCRIBE verbatim, and MqttSubscriptionManager's
constructor now clamps it exactly as the AdminUI driver form already persists.
-006: the DateTime write arm cast a negative long to ulong, so 1969-12-31 published a
timestamp ~584 million years in the future; it is now refused as ValueNotRepresentable.
An Unspecified kind was handed to ToUniversalTime(), which reads it as LOCAL — the same
authored instant encoded differently on the two nodes of a redundant pair; it is now
read as UTC.
-007: Format/FormatState enforced only null/empty, and nothing at all on deviceId, so
the type was not round-trip-closed. They now apply the parser's IsValidSegment (plus
'/', which only the format side can see). MqttWriteEncoder's own guards stay — TryEncode
returns an error rather than throwing, and that contract does not change.
Driver.Mqtt-006 (Low, concurrency). DisposeAsync disposed _gate while StopAsync
cancels the reconcile loop WITHOUT awaiting it, so a ReconcileAsync already in
flight could be inside _gate.WaitAsync, or on its way to the finally-release,
when the semaphore went away. The release then threw ObjectDisposedException
naming SemaphoreSlim, logged as a reconcile failure — telling an operator
nothing about what happened and hiding whatever the reconcile was really
failing on.
Left undisposed, matching MqttConnection's documented rule for its own lifecycle
primitives and its stated rationale: a late callback racing teardown should be a
benign no-op rather than an ObjectDisposedException naming the wrong type. Two
lifecycle types in one module disagreeing about this is what gets copied into
the third. Nothing is leaked — the gate holds no timer and no registration — and
ClaimAsync still re-checks _disposed under it, so no claim can be created after
dispose either way.
Test is deterministic rather than timing-dependent: the gate is taken before the
connect starts, so a MiniBroker in blackhole mode (TCP accepted, CONNECT never
answered) accepting the socket proves the claim is inside the gate when dispose
runs. RED: log.Captured contained "ObjectDisposedException".
Driver.Mqtt-007 (Low, error handling). OnReconnectedAsync throws when a
re-subscribe is granted zero filters — MqttConnection's contract is that a
throwing Reconnected subscriber tears the fresh session down and retries under
backoff, because a connected-but-deaf driver is the one outcome this path must
never serve. But when the live subscribed topics resolved to zero filters in the
first place it logged a warning and returned, reaching the same "nothing was
re-established" state by a different route and giving it the opposite answer.
Throw there too, and say so in the remarks so the type states ONE rule. It costs
no other tag — every live topic is in the set that resolved to nothing, so there
is nothing left flowing to protect, which is the whole reason the partial-
rejection case is exempt — and it is not permanent: the retry runs against
whatever Register has published by then.
Test reaches the state the only way production can: Register prunes
_subscribedTopics of the topics its new table no longer carries, but a SUBSCRIBE
already in flight records its own topic AFTER that prune ran, so a deploy landing
inside the round-trip leaves a live topic no authored tag resolves to. Paired
with the control that a reconnect with no live subscriptions at all stays a
no-op — throwing there would tear down the session of every driver whose tags
have not been subscribed yet.
Findings from the per-module review of Driver.Mqtt at b990adae
(code-reviews/Driver.Mqtt/findings.md records all ten; these are the fixed
ones).
Driver.Mqtt-001 (High) — MqttSubscriptionManager._subscribedTopics is a claim
about the broker session it established filters on, and AttachTo never cleared
it, but the manager OUTLIVES a session rebuild (AdoptOptions keeps it whenever
the ingest identity is unchanged). After a driver-host reconnect
(ShutdownAsync + InitializeAsync, the #527 watchdog's retry) or a
ReinitializeAsync that only changed the endpoint/credentials, the host's
re-subscribe resolved an empty pending set, sent no SUBSCRIBE at all, and left
the driver Connected/Healthy on a session carrying ZERO subscriptions — no
error, no Bad status, values frozen until the new session happened to drop.
AttachTo now forgets them, mirroring SparkplugIngestor.AttachTo's reset.
Driver.Mqtt-002 (High) — InitializeCoreAsync published _connection and
_primaryHost over whatever the driver already held, so a second initialize
stranded a connected, self-supervising broker session (plus a second Sparkplug
primary-host claim) that no later dispose could reach. Reachable without any
teardown of ours via DriverInstanceActor.AdoptConfigDuringInit. Now tears down
first, under the gate both callers already hold.
Driver.Mqtt-003 (Medium) — connectTimeoutSeconds is [Range]-annotated but
unvalidated on the runtime path; 0 makes every deadline fire immediately and a
negative value throws ArgumentOutOfRangeException out of ShutdownAsync and
DisposeAsync. Normalized once, at the seam every options instance passes.
Also: ShutdownAsync keeps the live last-message instant (-004), three usings
left behind by #512 removed (-005), stale remarks corrected (-009, -010), and
docs/drivers/Mqtt.md now distinguishes the two kinds of reconnect.
Tests 708 -> 713. All three regression tests were confirmed to fail against
the un-fixed code, with two controls that pass in either state.
Found on the docker-dev live gate, not in tests. Two drivers that faulted
during initialise (rtu-gate, opcua1) each rendered "0 tags" on /hosts against
two authored tags apiece, because a ledger that had never committed returned
SkippedTagReport.Empty.
A zero report is a positive claim -- "this driver skipped nothing" -- and
making it on behalf of a driver that never got as far as looking is exactly
the quiet inaccuracy #541 exists to remove. GetSkippedTags() and
SkippedTagLedger.Snapshot() now return null until the first committed build,
so the column renders the same em-dash it already used for a driver that
cannot report at all. Both are 'no answer'; neither is 'nothing skipped'.
Knock-on: a FOCAS driver whose only init threw now reports null rather than a
zero report, which is strictly more honest than the assertion the test
originally made.
A driver builds its RawPath -> definition table at init and tolerates a
per-tag miss: an unmappable TagConfig, an unparseable address, a
capability-matrix rejection. That tolerance is right -- one bad tag must not
take down the other few thousand. What was missing is any statement of the
fact afterwards. A skip is not an error and happens before any read, so the
driver stays Healthy, errors/5 min stays 0, Last error stays empty, and Last
read advances live off the tags that did map. On the wonder Makino in #540
that reading held while focas-z-34184 ignored 20 of its 22 tags.
New optional capability ISkippedTagReporter, backed by a shared
SkippedTagLedger so the reset/commit/cap rules are one implementation rather
than one per driver. The report -- authored count, exact skipped count, and a
capped sample of RawPath + reason -- rides DriverHealthChanged to a new Tags
column on /hosts, over the Phase 5 telemetry stream. No table: a driver-only
node has no ConfigDb to write to, the lesson from #521.
The issue named eight drivers. It is twelve -- every driver in
DriverTypeNames.All has an authored-tag skip path. Calculation (no scriptId),
MTConnect (no readable DataItem id), Galaxy (no attributeRef) and OpcUaClient
(no nodeId) were unlisted, and OpcUaClient's was the quietest of the twelve:
NamespaceMap drops such an entry with a bare `continue` and not even a log
line. SkippedTagReporterFleetTests pins the invariant reflectively over every
IDriver in src/Drivers/, so a thirteenth cannot re-introduce the silence.
Sql drops a tag at TWO points and its report is the union of both: a blob
that does not map, AND an identifier the 8.1 catalog gate rejects against the
live catalog. The second is what schema drift produces -- a renamed column, a
dropped view -- months after a deployment sealed green, and reporting only
the first would have that driver claim "0 skipped" while polling half its
tags, which is worse than reporting nothing because the column would then be
actively reassuring.
Deliberately additive to driver state, never a change of it. Latching
non-Healthy for a config problem would satisfy both halves of the #527
comms-loss conjunction -- 90 s without a successful read AND non-Healthy --
and a driver whose tags were ALL skipped has no successful reads by
construction, so it would reconnect-loop forever against a healthy device.
Three details that are load-bearing rather than incidental:
- The skip digest is part of the publish fingerprint. A skipped tag leaves
every other fingerprint component identical to a clean driver's, so without
it PublishHealthSnapshot's dedup swallows exactly the publish carrying the
signal -- the trap that already bit the rediscovery and host-status
channels. The digest covers the sample, not just the counts: a redeploy
that fixes one tag and breaks another leaves both counts unchanged.
- The count is exact; only the sample is capped, and the tooltip says so when
it is showing fewer than it counted. A truncated list that looked complete
would have an operator fix twenty tags and believe the job done.
- The ledger stages and commits, so an init that throws part-way leaves the
previous report standing. A partial snapshot would read as "we now skip
fewer tags", the opposite of the truth.
The proto field needs no companion presence flag, unlike host_statuses: a
singular message field carries real presence in proto3, and a has_ flag would
collide with protoc's generated HasSkippedTags.
Verified red-first three ways: dropping SkippedTagDigest from the fingerprint
fails the two dedup tests, removing the seam from one driver fails the fleet
guard, and dropping the catalog-gate leg fails the Sql union test. Full
solution builds with zero new warnings against 4e22f024.
Both `IDriver` members had no production call site. Their only consumer was
`MemoryTracking`, deleted with the driver-tier recycle machinery in #522, and
`GetMemoryFootprint`'s doc-comment claimed "polled every 30s by Core" — which
had not been true since v3, even before #522 removed the poller.
Owner decision on #525 was (a) delete rather than (b) build the process-wide
watchdog that would consume them. The driver-side implementations are in git
history and were mostly reusable; what was always missing is the trigger, and a
member nobody calls is how the misleading doc-comment survived this long.
Removed from `IDriver`, all 12 driver implementations, and every test stub —
plus the support code that existed only to feed them, which is the part a
member-only deletion would have left behind as dead weight:
- MTConnect's three per-entry byte-weight constants, its cached
`ProbeModelDataItemCount`, and `CountDataItems` — a full device-tree walk run
on every cache fill to populate a number with no remaining reader.
- OpcUaClient's `_discoveredNodeCount` field and the discovery-pass write to it.
- MQTT's `ApproxBytesPerAuthoredTag`.
Two behavioural notes, neither a change in what the software does:
- `AbCipTemplateCache` now has no production reset path. Its only caller was
AB CIP's flush, which itself had no caller — so nothing changes except how
visible the fact is. Recorded on the type, along with the correction that its
comment's claim about a device `ReinitializeAsync` also flushing it was never
true. A UDT redefined on a live controller keeps its stale shape until the
driver instance is rebuilt.
- MTConnect's `/probe` cache is still dropped, by `InvalidateProbeModel()` on an
Agent restart. That is now `internal` rather than `private` so the tests which
used the flush purely to empty the cache drive the real path instead — they
now cover a case that actually occurs in production. Several unrelated doc
comments cited `FlushOptionalCachesAsync` as the canonical CAS example and are
repointed to it.
Tests: the ones that existed only to assert on the removed members are deleted
(3 OpcUaClient, 3 Galaxy, 2 MQTT, 1 MTConnect, 1 AbCip). Worth noting one was
vacuous — `FlushOptionalCachesAsync_resets_footprint_counter` asserted a
footprint of 0 before the flush and 0 after with no discovery in between, so it
would have passed against a flush that did nothing at all.
Full suite green except 7 failures verified identical on master before and
after (4 AbLegacy integration with the compose profile down, 3
Host.IntegrationTests), checked by name rather than assumed.
Docs corrected where they described this as live: `DriverLifecycle.md` (which
carried the #525 placeholder), `drivers/AbCip.md`, `drivers/AbLegacy.md`, and
`v2/driver-stability.md` — whose "polls this every 30 s" + per-driver
`DriverConfig` memory budget were never built as written and are now banner-ed
as design intent rather than description.
Claude-Session: https://claude.ai/code/session_015p7wGqy3YpZNCpDzTpGMKo
`SparkplugCodec` handled scalars; `DataSet`, `Template` and `PropertySet` were skipped
with a warning. They now flatten to addressable tags (owner decision, recorded on the
issue):
Template → sibling metrics, `/`-joined, recursively: Motor → Motor/Speed, Motor/Stator/Temp
DataSet → one metric per cell, {column}/{rowIndex}: Recipe → Recipe/Step/0, Recipe/Target/1
PropertySet → node metadata, never tags — it describes a metric rather than being one
Flattening was chosen over OPC UA Structures because flattened scalars are consumable by
any client with no type dictionary, and the result mirrors how the `/raw` tree works.
**The row index is always present, including on row 0.** Emitting a bare column name for
a single-row table and an indexed one otherwise would make a tag's name depend on how many
rows the plant published — a table growing from one row to two would rename every tag
already authored against it.
**A DATA metric carries the parent's alias and no name**, so member names cannot be
composed until the alias table has resolved the parent. Expansion therefore happens in
`SparkplugIngestor.PublishStructuredMembers` — after resolution, at the single funnel both
the DATA and birth-value paths already pass through — not at decode time. The alias table
installs a binding per member so browse enumerates them and a DDATA member that omits its
datatype falls back to the birth's (guessing from the CLR type would read a signed Int32 of
-42 out of its unsigned field as 4294967254).
**Skip-and-warn survives, and refusal is whole** — the explicit requirement on the issue.
A template definition, an unnamed member, an extension value, a column/type mismatch, a
short row, or a payload past MaxDepth(5)/MaxMembers(512) refuses the ENTIRE metric. A
silently half-flattened UDT looks exactly like a complete one in the picker.
The browse picker offers the members and deliberately NOT the structured parent, which has
no value and no servable datatype. The rediscovery signature likewise tracks members rather
than the parent, or a UDT gaining a member would leave the signature unmoved.
Member paths contain `/`, which #509 already solved: the slashed name travels intact as
`metricName` while the derived tag Name is coerced to a legal RawPath segment.
Live-gated 3/3 against the Mosquitto fixture with the project-owned simulator extended to
publish a nested Template and a 2x2 DataSet. Falsified at three points: dropping the member
bindings, not expanding the parent, and refusing to flatten templates each turn exactly the
expected tests red.
Also fixes a regression from the #511 commit in the same branch: `AddOtOpcUaDriverFactories`
resolved `IDriverPrimaryRoleSource` with `GetRequiredService` but only `AddOtOpcUaRuntime`
registered it, so a graph wiring driver factories without the full runtime failed at
resolution. Two Host integration suites do exactly that and caught it; both extensions now
TryAdd the same concrete `RedundancyRoleView`, so the registration is order-independent and
the fail-loud resolve is kept.
Claude-Session: https://claude.ai/code/session_015p7wGqy3YpZNCpDzTpGMKo
`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
MqttDriver implemented no IWritable, so every MQTT node materialized read-only
regardless of what the operator authored. It now publishes.
Plain -> the tag's writeTopic; UTF-8 text (Raw/Scalar) or a bare JSON
literal (Json)
Sparkplug -> DCMD for a device metric, NCMD for an edge-node metric, carrying
the metric BY NAME with an explicit Datatype and no seq
Both at QoS 0, retain:false. Retain is deliberately not configurable — a retained
command is replayed by the broker on every future subscribe, including the
device's own reconnect, so one stale write would be re-applied forever.
writeTopic is a new, separate TagConfig key, and its ABSENCE is meaningful: the
write is refused BadNotWritable and the node is discovered ViewOnly. The issue's
"do not skip" warning drove the design — the one outcome worse than read-only
nodes is a node that looks writable, returns Good and publishes nothing. Reusing
the read topic would be worse still: it would echo back and read as a confirmed
device value. Browse-time writability is computed by the SAME encoder the write
path uses, so a node cannot advertise writability it would then refuse.
Good means published, not applied — MQTT has no application-level write ack, so
this is Galaxy's optimistic-Good posture and inherits its property: a failed
DEVICE write can never be surfaced. A failed PUBLISH is reported Bad; the
optimism covers what the device did with the command, never whether it was sent.
WriteIdempotent stays default-off.
The encoder is pure and lives in .Contracts, so both wire shapes are testable
without a broker. Unrepresentable values and types with no Sparkplug encoding are
refused rather than coerced — a Reference must not silently become a String on
the wire, and "not-a-number" must not become 0 on a live plant.
LIVE GATE PASSED against the real Mosquitto fixture on 10.100.0.35: 21/21
integration tests, including 6 new ones that observe the published message with
an INDEPENDENT broker subscriber — a fake asserting "publish was called" could
not tell the feature working from the feature publishing to the wrong topic.
The gate earned its keep: the NCMD test initially failed because NCMD is a SHARED
channel — the driver publishes its own rebirth request (Node Control/Rebirth) on
the very topic an edge-node metric write uses, and it arrived first. Correct
driver behaviour, wrong test; the watcher now matches on metric name. Documented,
because anything consuming that topic needs to know. DCMD has no contention.
Offline: 24 encoder + 9 driver tests. The four new status constants are NAMED so
StatusCodeParityTests can see them (#497/#519) — it went 258 -> 262 and validated
each against the pinned SDK.
Also corrects the Mqtt.md "Known gaps" table: prunes the six rows closed in this
round, and fixes the #507 row, which still described rediscovery as inert after
that issue was closed as superseded and its injection path deleted.
Claude-Session: https://claude.ai/code/session_015p7wGqy3YpZNCpDzTpGMKo
Five MQTT tracker items — four AdminUI/authoring defects plus the .Browser
layering exception. No runtime driver behaviour changes.
#513 payloadFormat in a Sparkplug blob. MqttTagConfigModel.ToJson wrote the key
unconditionally. Sharper than the issue states: PayloadFormat is the one Plain
field with a NON-NULLABLE typed backing, so the write did not preserve a retyped
tag's leftover — it INVENTED "payloadFormat":"Json" in a Sparkplug tag that never
had one. Now Plain-only; preserve-unknown-keys is pinned unchanged.
#509 slashed Sparkplug metric names. The mapper already carried metricName
verbatim; only the tag Name (a RawPath segment) tripped RawPaths.ValidateSegment,
which refused the batch whole — including Node Control/Rebirth, mandatory on
every Sparkplug edge node. ToRawSegment coerces the Name and leaves the address
untouched. Coercion is not injective, so DescribeNameCollisions refuses a
colliding set BY NAME: silently merging two metrics into one tag would be worse
than the refusal it replaces. Applies to every driver, not just MQTT — the
argument is about what a Name is, not about who produced it. The sanitiser is
pinned against RawPaths.ValidateSegment rather than a copied charset.
#510 stale rebirth affordance. _canRebirth was probed once at browse-open and
sessions are reaped for idleness, so a modal left open offered an action whose
token no longer resolved. Re-probed on arm AND on confirm (the reap can land
between the two, and confirm is the one path that publishes to a live broker);
the affordance retires with an explanation instead of vanishing or erroring.
#514 rebirth on a quiet plant. The tree is birth-driven and births are never
retained, so a plant that birthed before the window opened showed an empty tree —
and the scope came only from a tree selection, so the one action that would fill
the tree could not be armed. The session already accepted a bare {group}/{edgeNode}
("the prime rebirth target"); this adds the affordance. Edge-node scope only, not
a group broadcast. The rule is extracted to SparkplugRebirthScope so it is
testable — this repo has no bUnit — and is advisory: the session re-resolves and
refuses before publishing.
#512 .Browser -> .Driver layering. TWO extractions were needed, not the one the
issue anticipated: it costed this as "the client-options builder", but the browse
session decodes births itself, so moving only that would have left the reference
exactly where it was.
- MqttClientOptionsFactory (TLS, PEM CA-pin validator, credentials, protocol
mapping) -> new leaf .Transport project. NOT .Contracts: that is deliberately
transport-free and MqttClientOptions is an MQTTnet type, so .Contracts would
hand MQTTnet to ControlPlane. This is the fix the .Browser csproj comment had
already prescribed, against the issue's suggestion.
- The Sparkplug protocol layer (SparkplugTopic/MessageType, SparkplugCodec,
RebirthRequester) -> .Contracts, beside the Tahu wire schema it encodes.
Still exactly one copy of the TLS/CA-pin logic; MqttBrowserLayeringTests guards
the graph both ways.
Measured, not assumed: Driver.Mqtt.dll, Polly.Core and Serilog are now absent
from the AdminUI's output. Core.dll remains, because Driver.Sql.Browser has the
SAME violation, undocumented — the old comment blamed this browser for Core and
was wrong. Filed separately rather than fixed in passing.
Full suite green apart from the 7 known pre-existing failures (4 AbLegacy
integration, compose profiles not up; 3 Host.IntegrationTests).
Claude-Session: https://claude.ai/code/session_015p7wGqy3YpZNCpDzTpGMKo
Task 21 review — two Criticals sharing one root cause, plus four follow-ups.
C1/C2 root cause: `OnReconnectedAsync` opened with `Births.Clear(); _trackers.Clear();`
— "not housekeeping, the correctness step" — and that reset was missing from the
other two seams where the view underneath a surviving cache changes.
- C1: the ingestor OUTLIVES a session rebuild. `SessionIdentity` is a strict
superset of `IngestIdentity`, so changing only Host/Port/ClientId/credentials/
TLS/a timeout gives `!SameSession && SameIngest` — `ReinitializeAsync` tears the
session down and re-establishes on the same instance, and `TeardownAsync` touches
no ingest state (the resilience layer re-running `InitializeAsync` is the second
path). A node that rebound alias 5 during the changeover would publish Pressure's
value under the Temperature RawPath at Good. Hoisted into `ResetSessionState`,
called from `AttachTo` (earliest seam — a persistent session can push between
CONNACK and our SUBSCRIBE), `EstablishAsync` and `OnReconnectedAsync`.
- C2: `Register` pruned trackers but not births. While a node is unauthored its
traffic is dropped at `Dispatch`, so its cached birth FREEZES rather than
refreshing; drop-then-re-add across a week mis-routes at Good, and `Births` grew
monotonically. Now evicted on edge-node departure.
Deliberately NARROWER than "absent from ByScope": a device with no authored tags
under a still-authored node keeps receiving traffic, so its birth is live, not
frozen — evicting it would discard correct state. Pinned both ways.
- I1: a birth whose seq is unreadable produced a permanent debounce-paced rebirth
loop. "A birth arrived" is now tracked separately from "the birth established a
baseline". Writing the test showed the cap belonged wider than the review scoped
it: data-before-birth and unknown-alias loop identically (20 messages → 23 NCMDs
against a cap of 3), so all three missing-metadata reasons share one per-node
consecutive cap, re-armed by any applied birth. A seq gap stays uncapped — it
self-limits.
- I2: the oversize `WarnOnce` key was the raw topic, off a group-wide `#`
subscription. `HandleMessage` now parses and filters to authored nodes BEFORE the
size check (also skipping the protobuf parse for discarded traffic), and `_warned`
carries a hard ceiling so a future bad derivation degrades to silence.
- I3: array metrics slipped the unsupported-type gate — `ToDriverDataType` returns
the ELEMENT type, so a String-typed tag published a packed `byte[]` as base64 at
Good. Gated on `IsSparkplugArray`.
- I4: driver-level Sparkplug coverage for the composition-root lines T22 left
untested — the `OnDataChange` re-raise, `ReadAsync` off the shared cache,
subscribe/unsubscribe dispatch, and both directions of the mode gate.
Minors: M1 the oversize test fed unparseable bytes and passed with the size check
deleted (now a real NBIRTH + an at-the-ceiling control); M2 answered in-place (an
absent seq is refused WITHOUT becoming the baseline, so the NCMD assertion is the
complete check); M3 `HostStateObserved` raise wrapped; M5 the legacy `STATE/{host}`
form is now subscribed, so the parser's tolerance is reachable in production; M8
`ResolveBinding` prefers the NAME over a disagreeing alias; M9 a narrowing float
conversion refuses instead of publishing ±Infinity at Good (a publisher's own
infinity still passes through). M4 was already resolved by T22.
Also fixed a race in the new tests: `publish.Topics.Clear()` after a call that
dispatches rebirths off-thread must drain first — it made the C1 sequence-baseline
pin pass vacuously in the first falsifiability run.
Falsifiability: dropping the reset from AttachTo+EstablishAsync reddens 4 (C1);
dropping the Register eviction reddens 2 (C2); widening the eviction predicate to
the reviewer's literal phrasing reddens the keep-live-births pin (C2b). 545/545 MQTT
unit tests green (was 524); whole-solution `--no-incremental` build clean under TWAE.
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
RediscoverPolicy is now mode-dependent: UntilStable in Sparkplug B (a tag's
dataType is optional -- the birth certificate declares it, so the discovered
tree fills in asynchronously), Once in Plain (nothing about the authored set
arrives on the wire).
DiscoverAsync resolves each Sparkplug tag's datatype per pass from the live
BirthCache, with the ingest path's own precedence: authored dataType wins,
else the birth's, else the record default. An unsupported Sparkplug type
(DataSet/Template/PropertySet/Unknown) falls back rather than blanking the
tag. The authored tag SET is never conditional on a birth -- an authored tag
is part of the declared configuration, not something the plant grants by
publishing.
SparkplugIngestor.BirthObserved is wired to RaiseRediscoveryNeeded behind a
two-part change gate, which is the anti-storm mechanism rather than an
optimisation: fire only for a scope an authored tag binds, and only when the
birth's metric-name SET (ordered-distinct, ordinal) differs from the last one
seen for that scope. Edge nodes re-birth freely -- on their own timer, on
every reconnect via the late-join rebirth fan-out, and once per rebirth NCMD
the gap policy sends -- and firing on each of those would make a healthy plant
a permanent address-space-rebuild loop. No extra debounce: what survives the
gate is a real edit to the served tree, and delaying it would need its own
trailing-edge flush to avoid dropping the last change.
The signature map is NOT cleared on death/reconnect/ingest rebuild (the
ingestor drops its whole birth cache on reconnect, but "the driver forgot" is
not "the address space changed"); it is pruned when a redeploy stops
authoring a scope.
ScopeHint is the "Mqtt" discovery folder, deliberately not the Sparkplug scope
path the plan named: the discovered tree is flat, so an edge-node/device path
would name a subtree that does not exist and a consumer scoping a rebuild on
it would rebuild nothing. The scope is carried in Reason instead.
Falsifiability: always-fire reddens the identical-rebirth + reordered-rebirth
pins; always-authored-datatype reddens the birth-fill pin; dropping the
authored-scope filter reddens the unauthored-device pin. 524/524 MQTT unit
tests green (was 513).
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
Task 21 — the design doc's §3.6 correctness core. `SparkplugIngestor` owns the
authored `(group, node, device?, metric) → RawPath` index, the live `BirthCache`,
one `SequenceTracker` per authored edge node, and the rebirth policy; it routes
NBIRTH/DBIRTH/NDATA/DDATA/NDEATH/DDEATH/STATE into `OnDataChange` +
`LastValueCache`, or into a bounded, per-node-debounced rebirth NCMD.
Invariants held (and each pinned by a falsifiability control):
- Published reference is the RawPath, never a composed Sparkplug reference —
`DriverHostActor`'s dual-namespace fan-out is RawPath-keyed.
- Tags bind by stable metric NAME; the alias is only the per-birth lookup, so an
alias reused across a rebirth cannot mis-route.
- Every value goes through `SparkplugMetricBinding.Reinterpret` before publish.
- NDEATH never reaches `SequenceTracker.Accept` (it carries no seq); it is tied to
its birth by bdSeq instead.
- An invalid payload mutates nothing — no tracker, no alias table, no eviction.
- `HandleMessage` never throws on MQTTnet's dispatcher thread.
Supporting changes:
- `MqttTagDefinitionFactory.FromSparkplugTagConfig` — the driver had no way to
parse the Sparkplug descriptor keys at all; the P1 stub fields on
`MqttTagDefinition` were never populated. Mode selects the parser, never a
blob heuristic. `dataType` becomes optional in the Sparkplug shape (the birth
declares it), recorded via the new `DataTypeAuthored` flag.
- `MqttConnection` implements `IMqttPublishTransport` (bounded, refusal throws).
- `MqttDriver` dispatches every capability by mode, subscribes `spBv1.0/{group}/#`
(+ the configured STATE topic) once at connect, and re-subscribes + requests a
late-join rebirth on reconnect. `IngestIdentity` now names `MqttSparkplugOptions`,
closing the silent same-ingest gap its own ⚠️ comment warned about.
Primary-host STATE *publishing* is explicitly out of scope and warned about at
construction: it needs the retained-OFFLINE Last Will set at CONNECT time, and
shipping the ONLINE half alone is worse than shipping neither.
58 new tests (MQTT suite 455 → 513, all green).
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
Self-review of the commit before this one caught a defect in the contract it
published rather than in the code it ran. AcceptBirth's doc said it records
"a birth (NBIRTH/DBIRTH)". That is wrong on both halves of this type, and the
wrong version plants exactly the defect the bdSeq tie exists to prevent.
Only the NBIRTH restarts the Sparkplug sequence; a DBIRTH carries the next
number in the edge node's ongoing stream, so it belongs to Accept. And only
the NBIRTH and NDEATH carry bdSeq at all -- a DBIRTH has none to pass. So a
Task 21 that followed the old doc and routed a DBIRTH to AcceptBirth would do
two wrong things at once: rebase the sequence mid-stream, and wipe the node's
session token to null. A stale Last Will arriving afterwards would then find
nothing to compare against, fall through the deliberate fail-toward-stale
rule in IsDeathForCurrentSession, and kill the live node.
Renamed AcceptBirth -> AcceptNodeBirth so the DBIRTH call site reads wrong at
a glance rather than only in prose, documented the hazard on both methods,
and added DeviceBirth_ContinuesTheNodeSequence_AndLeavesTheSessionTokenAlone
to pin the shape at this type's own boundary -- the ingest state machine now
has something to fail against if it wires the call sites the other way round.
Falsifiability: mutating Accept to clear _birthBdSeq reddens exactly the new
test (1 RED), reverted. 29 tests, 438/438 for the MQTT suite.
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
SequenceTracker (Driver.Mqtt/Sparkplug/) holds one edge node's Sparkplug
stream-continuity state -- design doc SS3.6 invariant #3. Two independent
halves: the wrapping 0-255 seq counter that reports whether a message was
missed, and the bdSeq session token that ties an NDEATH to the NBIRTH it
belongs to.
Next-expected is (last + 1) & 0xFF, so 255 -> 0 is the sequence continuing.
The boundary is the whole task because it fails differently in each
direction: read the wrap as a gap and every edge node is asked to rebirth
once per 256 messages, so a busy node spends its life republishing births
instead of data; miss a real gap and the driver serves values it knows are
behind the device, at Good quality, indefinitely. Both directions are
asserted, plus two full wrap cycles so an off-by-one that only misfires at
one value has nowhere to hide.
A gap is reported once and the tracker then resynchronizes onto the observed
value -- holding the baseline at the pre-gap number would make every
following message report a gap too, so one lost message would become a
permanent rebirth storm, the same pathology as a wrong wrap reached by a
different route.
An out-of-range seq is refused, never masked. The codec hands seq over as a
ulong precisely so a spec-violating publisher's value is not truncated into a
plausible-looking one, and masking would finish the job it declined to do:
with the baseline at 255, a seq of 256 masks to 0 -- exactly what the wrap
expects next -- and the bogus message would be accepted as contiguous.
Refused values do not become the baseline either, so the next genuine message
is still measured against the last credible one.
A birth restarts the sequence via AcceptBirth rather than Accept, so it is
never itself a gap; a gap after a birth is still detected. An in-range but
non-zero birth seq is adopted rather than refused -- refusing it would demand
a fresh rebirth for every message from an otherwise-followable publisher. The
first message on a virgin tracker cannot be a gap (nothing to measure it
against) but leaves IsBirthSynchronized false, which is how Task 21 tells a
mid-stream late join from a synchronized node.
bdSeq exists to stop a late Last Will from killing a live node: a node's
connection drops, it reconnects and publishes a fresh NBIRTH, and only then
does the broker notice the old connection died and deliver its will carrying
the PREVIOUS session's bdSeq. Without the compare that stale NDEATH drives
every tag of a freshly-born healthy node to Bad. Unknowns fail toward stale
deliberately -- only a positive mismatch of two known tokens discards a
death, because acting on a death wrongly self-corrects at the next birth
(invariant #4) while ignoring a real one leaves a dead node's values flowing
Good forever. bdSeq is not a top-level field, so TryReadBdSeq extracts it
from the metric named bdSeq and runs it through ReinterpretSigned first: read
raw, a negative Int64 bdSeq becomes an enormous ulong -- a plausible-looking
session token minted out of nonsense.
Falsifiability verified, each mutation reverted after observing RED:
(a) no-wrap expected -> 2 RED; (b) Accept always true -> 5 RED; (c) bdSeq
compare always matches -> 2 RED; (d) mask out-of-range seq into range ->
2 RED. 28 tests, 437/437 for the MQTT suite.
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
Design §3.6 invariants #1/#2. A Sparkplug alias is scoped to ONE birth: after a
rebirth an edge node may point alias 5 at a different metric. So authored tags
bind by the stable metric NAME and the alias is a per-birth cache only —
RebuildFromBirth builds both indexes fresh and publishes them in one assignment,
never merging or upserting, including for an empty birth (which legitimately
clears the scope).
BirthCache keys scopes by the full (group, edgeNode, device?) triple and applies
the spec's node→device rules: an NBIRTH invalidates every DBIRTH under that node
(returning their metric sets for the STALE fan-out), a death evicts rather than
blanks so data-before-rebirth stays detectable. Reads are lock-free on MQTTnet's
dispatcher thread — an immutable snapshot swapped atomically per scope, the same
discipline MqttSubscriptionManager.AuthoredTable uses, with rebuilds landing in
place so a held table reference always observes the newest birth.
Running values are deliberately NOT stored here — LastValueCache owns those,
keyed by RawPath. SparkplugMetricBinding.Reinterpret exposes the birth datatype
to the codec's two's-complement fix, since a DATA metric carries no datatype.
Falsifiability: mutating RebuildFromBirth to merge reddened 5/19 tests (both
plan invariants); making the alias carry metric identity across a birth reddened
3/19, including the headline alias-reuse case.
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
SparkplugTopic (Driver.Mqtt/Sparkplug/) parses/formats spBv1.0 topics for
every message type (NBIRTH/DBIRTH/NDATA/DDATA/NDEATH/DDEATH/NCMD/DCMD/STATE).
TryParse never throws -- it is fed every topic a live spBv1.0/{group}/#
subscription delivers -- and rejects device/node-scope mismatches and MQTT
wildcard chars in a segment. STATE is handled honestly rather than force-fit
into the {group}/{type}/{node} mould: it parses both the v3.0
spBv1.0/STATE/{hostId} form and the legacy no-prefix STATE/{hostId} form
(tolerated on receive only -- Format/FormatState always emit v3.0). Format
gives Task 20's NCMD/DCMD write path a builder instead of hand-concatenation.
SparkplugDataType is a `global using` alias for the vendored proto's
generated Org.Eclipse.Tahu.Protobuf.DataType, not a second hand-duplicated
enum -- Metric.Datatype is a raw wire uint32 (no enum-typed field forces a
second CLR type to exist), and SparkplugCodec (Task 16, landed concurrently)
already casts straight to the generated type. A duplicate enum would be the
same enum-drift hazard this repo already names systemic (CLAUDE.md's driver
enum-serialization bug) and would force every downstream task to cast
between two value-compatible-but-nominally-different enums. ToDriverDataType()
maps per design doc SS3.5: Int8/UInt8 widen to Int16/UInt16 (no 8-bit
DriverDataType member), Float/Double to Float32/Float64 (there is no
DriverDataType.Double), Text/UUID/Bytes/File to String, *Array variants to
their element type (IsSparkplugArray carries the array bit separately), and
DataSet/Template/PropertySet/PropertySetList/Unknown return null -- an
explicit "unsupported, caller must skip+warn" rather than a guessed String.
The completeness test enumerates the live generated DataType member set
(via the alias) and asserts every member is mapped or on the explicit
unsupported list, so a future Tahu proto change is caught automatically
instead of silently falling through a stale duplicate enum's default.
Falsifiability verified by hand for three defect shapes (each reverted after
observing RED): wrong Int8 widening, a dropped mapping falling through
undetected, and inverted node/device topic scoping.
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
The try/catch stopped at Payload.Parser.ParseFrom, leaving the metric-projection
loop outside it — so the "never throws for any input" contract had a hole in
exactly the part that walks an attacker-shaped object graph. Widened to cover
parse AND projection.
Self-review finding; no test reddened, because a projection escape needs a
generated-code shape the vectors do not produce. That is the point: the guard is
the contract, not the observed behaviour of today's inputs.
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
Decodes Sparkplug-B wire bytes into a driver-side projection (SparkplugPayload /
SparkplugMetric / SparkplugValueKind) for the Task 21 ingest state machine.
- Never throws, for ANY input. It sits on MQTTnet's shared dispatcher thread, so
an escaping exception would stall delivery for every subscription on the
connection, not one tag. Garbage, truncation, zero-length, a valid protobuf of
another schema and an over-nested Template all resolve to a verdict.
- Zero-length input is INVALID, not "a payload with no metrics" — protobuf would
parse it as all-defaults, and that is how a truncated-to-nothing body gets
mistaken for a well-formed one.
- Explicit presence throughout (Has{Seq,Name,Alias,Datatype,Timestamp}), never a
zero-check: an NBIRTH legitimately carries seq = 0, and every DATA metric after
a birth carries an alias with no name and no datatype.
- Values are projected RAW, boxed, with the value oneof reported as an explicit
ValueKind — Absent / Null / Scalar / Unsupported all mean different things and
three of them carry a null value. DataSet/Template/extension decode as
Unsupported (v1 scope) rather than throwing or silently vanishing.
- ReinterpretSigned() undoes Sparkplug's two's-complement-in-an-unsigned-field
encoding of Int8/16/32/64. Kept out of decode because a DATA metric carries no
datatype — only the consumer, holding the birth's alias table, knows which
applies. Skipping it publishes 4294967254 for a tag whose value is -42.
- Datatype is carried as the generated Org.Eclipse.Tahu.Protobuf.DataType; the
SparkplugDataType map is Task 17's and is applied downstream (Task 21).
Golden vectors: nbirth.bin (seq=0, named/aliased catalog, a negative Int32, an
is_null metric, a DataSet metric) + ndata.bin (alias-only metrics, no name, no
datatype) are hand-built by SparkplugGoldenPayloads, committed, and pinned by a
drift guard that rebuilds and byte-compares them on every run — plus a test that
they actually reach the output directory, since a missing copy item is invisible
in source.
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
MQTTnet 5 does not throw on an unsuccessful CONNACK — it returns the reason in
MqttClientConnectResult.ResultCode and v5 removed v4's ThrowOnNonSuccessfulConnectResponse,
so ConnectCoreAsync's unconditional SetState(Connected) sealed a wrong-password deployment
green: DriverState.Healthy / HostState.Running on a session that never authenticated.
Caught by the Task-13 Mosquitto fixture; 240 offline tests missed it.
ConnectCoreAsync now inspects the CONNACK and raises MqttConnectRejectedException.
Credentials/identity/protocol/Last-Will refusals are unrecoverable and set Faulted, which
stops the reconnect supervisor; transient refusals (ServerUnavailable, ServerBusy,
QuotaExceeded, UseAnotherServer, ConnectionRateExceeded, and anything unrecognised) stay
Reconnecting under backoff. MqttDriverProbe now shares the rejection wording, so the
AdminUI Test-connect button and the running driver can no longer disagree.
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
C1 (Critical) — DisposeAsync went straight to TeardownAsync with no lifecycle-gate
wait, reopening the orphaned-connection class. Interleaving: ReinitializeAsync's
rebuild branch holds the gate mid-InitializeCoreAsync, past its own teardown but
before `_connection = connection`; an ungated dispose sees a null connection, does
nothing, and sets `_disposed`; the rebuild then publishes a live connection plus a
host-probe loop that every later dispose short-circuits past. Not proven reachable
today (DriverInstanceActor.PostStop calls the gated ShutdownAsync), but MqttDriver
publicly implements IAsyncDisposable, which invites `await using`.
- DisposeAsync now takes the gate with the same bounded wait + fallback teardown
ShutdownAsync uses, and sets `_disposed` BEFORE the wait.
- InitializeCoreAsync re-checks `_disposed` after the connect and disposes the
connection it just built rather than publishing it — this closes the residual
window on the bounded-timeout fallback path.
- The doc comment no longer claims parity with ShutdownAsync it did not have, and
stops conflating "don't Dispose() the semaphore object" with "don't WaitAsync".
I1 (Important) — the SameSession == false rebuild branch had no test driving it.
Adds three: an endpoint-changing delta rebuilds and Faults on a refused connect;
an ingest-only delta (MaxPayloadBytes) ALSO rebuilds, pinning that IngestIdentity
is nested inside SessionIdentity; and DisposeAsync serializes behind a lifecycle
operation parked at a new internal BeforeConnectHookForTests seam (mirroring
MqttConnection's AfterConnectHookForTests, which exists for the same race class).
Minors: comments recording that IngestIdentity names no Sparkplug field and must
grow one in P2 (tasks 21/22), and why _options/_subscriptions/_authoredRawPaths
get looser memory discipline than _health/_hostState.
Falsifiability: reverting DisposeAsync to the ungated form reddens exactly the new
serialization test ("Shouldly.ShouldAssertException : raced"); forcing SameSession
to always-true reddens exactly the two new rebuild tests. 240/240 MQTT tests pass;
forced rebuild of the driver project is 0 warnings under TreatWarningsAsErrors.
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
Task 9. Adds MqttDriverFactoryExtensions (DriverTypeName = DriverTypeNames.Mqtt,
direct deserialization of MqttDriverOptions — no intermediate DTO, mirroring
OpcUaClientDriverFactoryExtensions), the DriverTypeNames.Mqtt constant, and both
host wiring sites: the factory in DriverFactoryBootstrap.Register and the probe in
AddOtOpcUaDriverProbes (the admin-node path Program.cs calls in its hasAdmin
block — a probe wired only on driver nodes makes Test-connect silently dead).
Carried-forward items:
- Converges every MQTT config-parsing seam onto ONE JsonSerializerOptions —
MqttJson.Options, in .Contracts alongside MqttDriverOptions. It replaces the
probe's internal JsonOpts and the browser's separate private copy; the factory,
the probe, MqttDriver.ParseOptions and MqttDriverBrowser now all parse through
it. .Contracts is the only assembly all four consumers reference, and the
browser's reference to the runtime .Driver project is a documented layering
exception scheduled for removal — anchoring the options there would resurrect
the duplicate the day it goes away.
- Replaces the "Mqtt" literals in MqttDriverProbe, MqttDriverBrowser and
MqttDriver with the constant (string value unchanged).
- Tightens MqttDriverProbeTests.ProbeAsync_EnumAsName: it asserted only
Ok == false + non-empty message, which is also exactly what a JSON-parse
failure produces — so it stayed green under the very regression it names.
It now asserts the probe got past the parse and reached the network.
Falsifiability: deleting JsonStringEnumConverter from MqttJson.Options reddens 9
tests across 4 suites, including the tightened probe test (message becomes
"Config JSON is invalid: The JSON value could not be converted to
MqttProtocolVersion") — which the pre-fix assertions would have passed.
Also references the MQTT driver from Core.Abstractions.Tests so
DriverTypeNamesGuardTests' reflective bin scan discovers the new factory and the
constant/factory parity check stays honest.
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
Composes MqttConnection + MqttSubscriptionManager + LastValueCache into the
IDriver / ITagDiscovery / ISubscribable / IReadable / IHostConnectivityProbe /
IRediscoverable capability set.
- Discovery replays ONLY the authored raw tags (RediscoverPolicy = Once,
SupportsOnlineDiscovery = false) — a chatty broker can never auto-provision.
- Composition order is register -> AttachTo -> ConnectAsync; the manager's
Reconnected handler is passed through unwrapped so its throw-on-total-failure
still tears a deaf session down.
- ReinitializeAsync applies a tag-only delta in place and never faults on a bad
one; a session-changing delta rebuilds.
- ReadAsync serves the last-value cache and degrades per reference
(BadWaitingForInitialData), never throwing for the batch.
- FlushOptionalCachesAsync is a no-op: the last-value cache IS IReadable.
- Adds MqttDriverOptions.RawTags (the authored-tag delivery mechanism every
other driver's options DTO already has) and promotes MaxPayloadBytes from a
manager ctor knob to an operator-facing key.
- Converges on MqttDriverProbe.JsonOpts rather than a second, divergent
JsonSerializerOptions.
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
Test-connect probe for the Mqtt driver type: parses MqttDriverOptions
(shared enum-as-name JsonSerializerOptions), opens a bounded MQTT CONNECT
via MqttConnection.BuildClientOptions with a distinct -probe-{guid8}
client-id suffix, and classifies the outcome. Live-probed against
MQTTnet 5.2.0.1603 to confirm the real contract: a broker-rejected
CONNACK is a MqttClientConnectResult.ResultCode, never a thrown
exception, and timeout classification checks the deadline token itself
rather than switching on exception type (which varies unpredictably
between MqttConnectingFailedException and bare OperationCanceledException
for the same frozen-peer shape).
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
C1 (CRITICAL). AuthoredTable routed any wildcard-authored tag into `Wildcards`
and never into the concrete topic index. But the two paths that reconstruct
state from a SUBSCRIBED FILTER STRING — OnReconnectedAsync's re-subscribe set
and DegradeTopic — both looked up that concrete-only index, and
`_subscribedTopics` keys on the wildcard PATTERN ("f/+/temp"). So:
- reconnect resolved zero filters for a wildcard tag, hit a silent early
return, and issued NO subscribe. The cache keeps its last Good value, so the
tag never turns Bad — it just stops updating forever behind a connection
reporting healthy. Exactly the silent-death mode MqttConnection's own remarks
warn about, left unguarded for wildcards.
- DegradeTopic missed too, so a SUBACK rejection of a wildcard filter degraded
nothing and left the tag at BadWaitingForInitialData.
Fix: AuthoredTable now carries `ByFilter` (EVERY def, keyed by its authored
topic filter, wildcards included) alongside `ByExactTopic` (concrete only) and
`Wildcards`. Delivery matches an incoming published topic — which never carries
a wildcard — so it keeps using ByExactTopic + the comparer scan. Every path
keyed on a filter string uses ByFilter. The distinction is documented on the
record. The silent early return is now a Warning naming the orphaned topics.
Also in this pass:
- I2: bounded decode on the dispatcher thread. A body over `MaxPayloadBytes`
(default 1 MiB, ctor-settable) is refused BEFORE any GetString/JsonDocument
parse and degrades its own tags. Unbounded decode on the shared dispatcher is
paid by every subscription, not just the offending topic. NOTE: promoting this
to an operator-facing MqttDriverOptions key (+ WithMaximumPacketSize) needs a
.Contracts edit this task is scoped out of; flagged in the XML docs.
- I3: integral-valued reals now coerce to integer tags. JS/Python edge gateways
serialize an integer as 5.0, and TryGetInt32/int.TryParse are syntactic — an
Int32 tag fed by such a gateway silently never received data. Parsed via
decimal so integrality and range are exact across Int64/UInt64. A genuinely
fractional 5.5 is still refused, never rounded.
- I4: the JSON document is parsed ONCE per message and shared across the whole
fan-out (the documented "one document, one JSONPath per signal" shape was
re-parsing per tag). Zero-alloc via a ref struct when no Json tag matches.
- I5: pinned the documented JSON-string-holding-a-number coercion end-to-end.
- Minor: Register now prunes `_subscribedTopics` / `_handleByRawPath` entries for
tags a redeploy dropped, so a deleted topic stops being re-subscribed forever.
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
MqttSubscriptionManager is the P1 plain-MQTT ingest path: it holds the authored
RawPath → MqttTagDefinition table behind the shared EquipmentTagRefResolver,
establishes one SUBSCRIBE per distinct authored topic, and turns each inbound
message into a LastValueCache update plus an OnDataChange notification.
Load-bearing choices, each pinned by a falsified test:
- The published reference IS the RawPath (def.Name), never the topic and never
the TagConfig blob — DriverHostActor's dual-namespace fan-out is RawPath-keyed,
so any other key passes every unit test and delivers nothing in production.
- One message fans out to EVERY tag on its topic; several tags routinely share a
topic with different jsonPaths, and stopping at the first match silently starves
the rest.
- An unauthored topic raises nothing: MQTT ingest never auto-provisions.
- Wildcard-authored topics (accepted by the parser, warned at deploy) match via
MQTTnet's own MqttTopicFilterComparer, so '+'/'#' behave as a broker would.
Concrete topics stay a single lookup; the wildcard scan runs only when one exists.
- Retained seeds are honoured natively on MQTT 5.0 (retain handling) AND filtered
client-side on the retain flag, because 3.1.1 brokers always replay.
- Nothing throws on MQTTnet's dispatcher thread: a malformed payload degrades that
tag (BadDecodingError / BadTypeMismatch), and a throwing OnDataChange subscriber
is contained without starving the tags behind it.
- The manager issues the FIRST subscribe itself — Reconnected deliberately does not
fire after the initial ConnectAsync.
- Reconnect re-subscribe: total failure THROWS (MqttConnection then tears the
session down and retries under backoff, rather than serving a connected-but-deaf
driver); a partial SUBACK rejection degrades only the denied refs, because
retrying forever over one ACL-denied topic would take every tag dark.
MqttConnection gains a MessageReceived observer (fired on the dispatcher, throwing
observers contained) and a bounded SubscribeAsync under its own linked-CTS deadline
— deliberately not MqttClientOptions.Timeout, which already governs every MQTTnet
op. A refused filter is an outcome, not an exception; only the SUBSCRIBE itself
failing throws. Classify() is parameterised by operation name (messages unchanged
for connect).
JSONPath is a documented subset ($, $.a.b, $['a'], $.a[0]); filters/slices/
recursive descent report a miss rather than pulling in a JSONPath package for an
expression form that selects a set where a tag needs one scalar.
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
Closes the connect-vs-connect defect: MQTTnet throws (and raises no DisconnectedAsync)
on a connect-while-connected, so a caller's ConnectAsync and the reconnect supervisor
corrupted each other in both directions. Both paths now check first; when the supervisor
finds the session already restored it stands down WITHOUT firing Reconnected.
Reconnected becomes Func<CancellationToken, Task>, fed from the lifetime token and capped
at ConnectTimeoutSeconds, so a hung re-subscribe can no longer park the supervisor.
Connected is published only after the re-subscribe succeeds; a supervisor that dies now
reports Faulted instead of Reconnecting forever.
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
LastValueCache bridges MQTT's subscribe-first push model to the OPC UA
server's polled IReadable.ReadAsync: the subscription path calls Update()
per RawPath, the read path calls Read(). Read never throws; an unseen
RawPath returns BadWaitingForInitialData (0x80320000) rather than an
exception or null, so a batch covering many references degrades per-ref
instead of failing wholesale.
Deviates from the plan's GoodNoData snippet: GoodNoData is reserved
repo-wide for "the historian window held no samples" (NullHistorianDataSource,
OtOpcUaNodeManager HistoryRead paths); BadWaitingForInitialData is the
established convention for "no live value observed yet" (CalculationDriver,
VirtualTagEngine, FOCAS, AddressSpaceApplier). Keyed by RawPath per the v3
driver-reference identity, not a topic/JSON-path-derived key.
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
Review follow-ups on MqttConnection (Task 3):
- Every certificate test asserted rejection, so the accept branch was
unreachable-by-regression. Adds a leaf genuinely issued by the pinned CA and
asserts acceptance.
- ValidateAgainstPinnedCa never seeded ChainPolicy.ExtraStore from the incoming
chain, so a leaf behind an intermediate delivered during the handshake failed
despite a legitimate path to the pinned root. Seeds from both the incoming
chain's elements and its ExtraStore; CustomRootTrust still means only the
pinned roots may terminate the chain.
- A DisposeAsync racing an in-flight connect escaped as an unclassified
exception; it now folds into ObjectDisposedException.
- Promotes the single-caller concurrency invariant into the type remarks, with
the accurate blast radius (a leaked live connection, not a benign throw).
Serialising the lifecycle remains Task 4's job.
- X509Chain.Build can throw; an exception escaping a TLS validation callback is
an opaque handshake crash, so it is caught and refused.
- Adds a connect-retry test (Task 4's reconnect loop reuses the instance) and a
disposed-then-connect test.
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
Joseph Doherty