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+# Cert-action audit logging + `OpcUaProbeResult` dead-letter tidy — Implementation Plan
+
+> **For Claude:** REQUIRED SUB-SKILL: Use superpowers-extended-cc:subagent-driven-development to implement this plan task-by-task.
+
+**Goal:** Record certificate Trust/Untrust/Delete actions to the `ConfigAuditLog` DB table
+via the existing `IAuditWriter`/`AuditWriterActor` path (the first live structured audit
+emit site), and silence the benign `OpcUaProbeResult` dead-letters in three Runtime actors.
+
+**Architecture:** Item 1 adds an `ActorAuditWriter : IAuditWriter` AdminUI adapter (Tells the
+`AuditWriterActorKey` cluster-singleton proxy, mirroring `AdminOperationsClient`), a pure
+`CertAuditEvents` factory, and audits at the `CertificateStoreManager` choke point. Item 2
+adds an intentional-drop `Receive<…OpcUaProbeResult>(_ => {})` to three actors (the
+`PeerProbeSupervisor.cs:69` idiom). No EF migration, no Commons/proto/interface change, no bUnit.
+
+**Tech Stack:** .NET 10, Akka.NET (Akka.Hosting `ActorRegistry`), Blazor Server (AdminUI),
+EF Core (`ConfigAuditLog` — table already exists), `ZB.MOM.WW.Audit` package
+(`IAuditWriter`/`AuditEvent`), xUnit + Shouldly, Akka.TestKit.
+
+**Design:** `docs/plans/2026-06-19-cert-audit-and-probe-deadletter-tidy-design.md`
+**Branch:** `feat/cert-audit-and-probe-tidy` (off master `40e8a23e`; design committed `e8c75cc3`)
+
+**Standing guardrails:** stage by explicit path (never `git add .`); never stage
+`sql_login.txt`, `Host/pki/`, `docker-dev/docker-compose.yml`, `pending.md`, `current.md`,
+`stillpending.md`. No `--no-verify`, no force-push. `dangerouslyDisableSandbox: true` for
+build/test/rig. Finish = merge to master + push.
+
+**Dependency graph:** `{T1 ∥ T3} → T2 → T4`. T1 (AdminUI cert-audit core) and T3 (Runtime
+actor drops) touch disjoint projects ⇒ dispatch their implementers concurrently. T2 depends
+on T1 (uses `CertAuditEvents` + `IAuditWriter`). T4 is the final gate.
+
+---
+
+### Task 0 (do this once, before T1/T2): Confirm the `AuditEvent` / `IAuditWriter` / `AuditOutcome` shape
+
+Not a code task — a **read** the T1/T2 implementer MUST do first so the factory matches the
+real package type (it lives in the external `ZB.MOM.WW.Audit` assembly, not this repo).
+
+- Go-to-definition / decompile `ZB.MOM.WW.Audit.AuditEvent`, `IAuditWriter`,
+ and the `Outcome` enum type. Confirm: exact property names + whether it's a record with a
+ primary ctor or settable inits; the `Outcome` enum member names (the design assumes
+ `Success` / `Failure` — verify); the `CorrelationId` property type (Guid? / a CorrelationId
+ struct / nullable).
+- Ground truth for how the existing code populates it:
+ `src/Server/ZB.MOM.WW.OtOpcUa.ControlPlane/Audit/AuditWriterActor.cs:97-107` reads
+ `EventId, OccurredAtUtc, Actor, Category, Action, SourceNode, DetailsJson, CorrelationId,
+ Outcome`. Mirror those names exactly.
+- If any assumed field/name differs, adjust the T1 factory code below accordingly (the
+ shape is the contract; the literal property names must match the package).
+
+---
+
+### Task 1: Cert-audit core — `ActorAuditWriter` + `CertAuditEvents` factory + DI + unit tests
+
+**Classification:** standard
+**Estimated implement time:** ~5 min
+**Parallelizable with:** Task 3
+
+**Files:**
+- Create: `src/Server/ZB.MOM.WW.OtOpcUa.AdminUI/Audit/ActorAuditWriter.cs`
+- Create: `src/Server/ZB.MOM.WW.OtOpcUa.AdminUI/Audit/CertAuditEvents.cs`
+- Modify: `src/Server/ZB.MOM.WW.OtOpcUa.AdminUI/EndpointRouteBuilderExtensions.cs` (register `IAuditWriter` near line 55)
+- Test: `tests/Server/ZB.MOM.WW.OtOpcUa.AdminUI.Tests/Audit/CertAuditEventsTests.cs`
+- Test: `tests/Server/ZB.MOM.WW.OtOpcUa.AdminUI.Tests/Audit/ActorAuditWriterTests.cs`
+
+**Step 1 — Write `CertAuditEventsTests` (failing).** Cover trust/untrust/delete × success/failure:
+- `Build("Trust", "trusted", thumb, "alice", success: true, error: null)` ⇒ `Category=="Certificate"`,
+ `Action=="Trust"`, `SourceNode==thumb`, `Actor=="alice"`, `Outcome` is the success member,
+ `DetailsJson` contains the store + thumbprint, `EventId != Guid.Empty`.
+- A failure case (`success: false, error: "certificate not found in rejected"`) ⇒ `Outcome` is the
+ failure member and `DetailsJson` includes the error text.
+Use Shouldly. (Assert `DetailsJson` by `ShouldContain` substrings, not exact JSON, to stay robust.)
+
+**Step 2 — Write `CertAuditEvents`:**
+```csharp
+using System.Text.Json;
+using ZB.MOM.WW.Audit; // confirm namespace in Task 0
+
+namespace ZB.MOM.WW.OtOpcUa.AdminUI.Audit;
+
+///
+/// Pure factory for the canonical emitted on a certificate-store
+/// mutation (Trust / Untrust / Delete). Separated from CertificateStoreManager so the
+/// event shape is unit-testable without a filesystem or an actor system.
+///
+public static class CertAuditEvents
+{
+ /// The audit category for all certificate-store actions.
+ public const string Category = "Certificate";
+
+ /// Builds the audit event for one certificate action and outcome.
+ /// The action verb: Trust / Untrust / Delete.
+ /// The PKI sub-store acted on (e.g. trusted / rejected).
+ /// The certificate thumbprint.
+ /// The authenticated principal performing the action.
+ /// Whether the action succeeded.
+ /// The failure message when is false; otherwise null.
+ /// A canonical audit event ready for .
+ public static AuditEvent Build(
+ string action, string store, string thumbprint, string actor, bool success, string? error)
+ {
+ var details = JsonSerializer.Serialize(new
+ {
+ store,
+ thumbprint,
+ error = success ? null : error,
+ });
+
+ return new AuditEvent
+ {
+ EventId = Guid.NewGuid(),
+ OccurredAtUtc = DateTimeOffset.UtcNow,
+ Actor = actor,
+ Category = Category,
+ Action = action,
+ SourceNode = thumbprint,
+ DetailsJson = details,
+ // CorrelationId / Outcome property types per Task 0. Outcome member names assumed
+ // Success / Failure — confirm and adjust.
+ Outcome = success ? AuditOutcome.Success : AuditOutcome.Failure,
+ };
+ }
+}
+```
+(Adjust property/enum names to the real package per Task 0. If `AuditEvent` uses a positional
+record ctor instead of init-setters, switch to the ctor form.)
+
+**Step 3 — Write `ActorAuditWriterTests` (failing).** Use Akka.TestKit: register a `TestProbe`
+in an `ActorRegistry` under `AuditWriterActorKey`, construct `ActorAuditWriter(registry)`, call
+`WriteAsync(evt)`, assert the probe `ExpectMsg()` equal to `evt`. (Mirror how other
+AdminUI TestKit tests build an `ActorRegistry` + register a key — search the AdminUI.Tests project.)
+
+**Step 4 — Write `ActorAuditWriter`** (copy the `AdminOperationsClient` resolve idiom):
+```csharp
+using Akka.Actor;
+using Akka.Hosting;
+using ZB.MOM.WW.Audit;
+using ZB.MOM.WW.OtOpcUa.ControlPlane; // AuditWriterActorKey
+
+namespace ZB.MOM.WW.OtOpcUa.AdminUI.Audit;
+
+///
+/// backed by the AuditWriterActor cluster singleton registered
+/// in AddOtOpcUaControlPlane. Resolves the singleton proxy from
+/// at construction (mirroring AdminOperationsClient); is a
+/// best-effort, non-blocking Tell — the actor owns batching, dedup, and flush.
+///
+public sealed class ActorAuditWriter : IAuditWriter
+{
+ private readonly IActorRef _proxy;
+
+ /// Initializes a new instance resolving the audit-writer singleton proxy.
+ /// The actor registry to resolve the audit-writer singleton proxy.
+ public ActorAuditWriter(ActorRegistry registry) => _proxy = registry.Get();
+
+ ///
+ public Task WriteAsync(AuditEvent evt, CancellationToken ct = default)
+ {
+ _proxy.Tell(evt);
+ return Task.CompletedTask;
+ }
+}
+```
+(Confirm the exact `IAuditWriter.WriteAsync` signature in Task 0 and match it.)
+
+**Step 5 — Register in DI.** In `EndpointRouteBuilderExtensions.cs`, next to
+`services.AddSingleton();` (line ~55):
+```csharp
+services.AddSingleton();
+```
+(Confirm `ActorRegistry` is resolvable in this method's host — it is, Akka.Hosting registers it
+as a singleton; `AdminOperationsClient` proves the pattern works in AdminUI.)
+
+**Step 6 — Run tests + build:**
+`dotnet test tests/Server/ZB.MOM.WW.OtOpcUa.AdminUI.Tests --filter "FullyQualifiedName~Audit"` → green.
+
+**Step 7 — Commit** (stage by path):
+`git add src/Server/ZB.MOM.WW.OtOpcUa.AdminUI/Audit/ src/Server/ZB.MOM.WW.OtOpcUa.AdminUI/EndpointRouteBuilderExtensions.cs tests/Server/ZB.MOM.WW.OtOpcUa.AdminUI.Tests/Audit/`
+then `git commit -m "feat(adminui): IAuditWriter adapter + cert-action audit-event factory"`.
+
+---
+
+### Task 2: Wire audit into `CertificateStoreManager` + `Certificates.razor` + extend manager tests
+
+**Classification:** standard
+**Estimated implement time:** ~5 min
+**Parallelizable with:** none (depends on Task 1)
+
+**Files:**
+- Modify: `src/Server/ZB.MOM.WW.OtOpcUa.AdminUI/Certificates/CertificateStoreManager.cs`
+- Modify: `src/Server/ZB.MOM.WW.OtOpcUa.AdminUI/Components/Pages/Certificates.razor:194-205`
+- Test: `tests/Server/ZB.MOM.WW.OtOpcUa.AdminUI.Tests/Certificates/CertificateStoreManagerTests.cs`
+
+**Step 1 — Extend `CertificateStoreManagerTests` (failing).** Add a recording fake `IAuditWriter`:
+```csharp
+private sealed class RecordingAuditWriter : ZB.MOM.WW.Audit.IAuditWriter
+{
+ public List Events { get; } = new();
+ public Task WriteAsync(ZB.MOM.WW.Audit.AuditEvent evt, CancellationToken ct = default)
+ { Events.Add(evt); return Task.CompletedTask; }
+}
+```
+Change the test ctor to build `_audit = new RecordingAuditWriter();` and
+`_sut = new CertificateStoreManager(_root, _audit);`. Add tests:
+- `Trust_success_writes_one_success_audit_event` — seed a rejected cert, `Trust(thumb, "alice")`,
+ assert `_audit.Events` has one event with `Action=="Trust"`, success outcome, `SourceNode==thumb`.
+- `Delete_not_found_writes_one_failure_audit_event` — `Delete("trusted", unknownThumb, "bob")`,
+ assert one event, failure outcome.
+- Confirm the existing (no-audit-arg) assertions still pass via the defaulted test ctor.
+
+**Step 2 — Modify `CertificateStoreManager`:**
+- Add field `private readonly IAuditWriter _audit;`.
+- Production ctor: `public CertificateStoreManager(IConfiguration config, IAuditWriter audit)` —
+ set `_audit = audit;` (and keep the pki-root read).
+- Internal test ctor: `internal CertificateStoreManager(string pkiRoot, IAuditWriter? audit = null)`
+ → `_audit = audit ?? NullAuditWriter`. (Use a tiny private no-op `IAuditWriter` if the package
+ has no Null impl — confirm in Task 0.)
+- Add the actor param to the three public methods and emit after computing the result:
+```csharp
+public CertActionResult Trust(string thumbprint, string actor)
+{
+ var r = Move("rejected", "trusted", thumbprint);
+ Audit("Trust", "rejected→trusted", thumbprint, actor, r);
+ return r;
+}
+// Untrust(thumbprint, actor) → Move("trusted","rejected",…) + Audit("Untrust", "trusted→rejected", …)
+// Delete(store, thumbprint, actor) → existing body + Audit("Delete", store, …, r) at each return
+
+private void Audit(string action, string store, string thumbprint, string actor, CertActionResult r)
+ => _audit.WriteAsync(CertAuditEvents.Build(action, store, thumbprint, actor, r.Success, r.Error));
+```
+Ensure **every** return path of `Delete` (invalid store, invalid thumbprint, not-found, success,
+IO failure) is audited — simplest is to compute the `CertActionResult` into a local, `Audit(...)`,
+then return it. Keep `_audit.WriteAsync(...)` fire-and-forget (returns a completed task).
+
+**Step 3 — Modify `Certificates.razor` `ConfirmAction` (line 194):** capture the actor and thread it:
+```csharp
+var actor = authState.User.Identity?.Name ?? "system";
+var result = p.Verb switch
+{
+ "trust" => CertManager.Trust(p.Thumbprint, actor),
+ "untrust" => CertManager.Untrust(p.Thumbprint, actor),
+ "delete" => p.Kind switch
+ {
+ StoreKind.Trusted => CertManager.Delete("trusted", p.Thumbprint, actor),
+ StoreKind.Rejected => CertManager.Delete("rejected", p.Thumbprint, actor),
+ _ => CertActionResult.Fail($"cannot delete from {p.Kind}"),
+ },
+ _ => CertActionResult.Fail("unknown action"),
+};
+```
+(`authState` is already in scope from the FleetAdmin re-check at line 185.)
+
+**Step 4 — Test + build:**
+`dotnet test tests/Server/ZB.MOM.WW.OtOpcUa.AdminUI.Tests --filter "FullyQualifiedName~CertificateStoreManager"` → green;
+`dotnet build src/Server/ZB.MOM.WW.OtOpcUa.AdminUI` → 0 errors (proves the razor compiles).
+
+**Step 5 — Commit:**
+`git add src/Server/ZB.MOM.WW.OtOpcUa.AdminUI/Certificates/CertificateStoreManager.cs src/Server/ZB.MOM.WW.OtOpcUa.AdminUI/Components/Pages/Certificates.razor tests/Server/ZB.MOM.WW.OtOpcUa.AdminUI.Tests/Certificates/CertificateStoreManagerTests.cs`
+then `git commit -m "feat(adminui): audit cert Trust/Untrust/Delete to ConfigAuditLog"`.
+
+---
+
+### Task 3: `OpcUaProbeResult` dead-letter tidy — three actor drop handlers + guard test
+
+**Classification:** small
+**Estimated implement time:** ~4 min
+**Parallelizable with:** Task 1
+
+**Files:**
+- Modify: `src/Server/ZB.MOM.WW.OtOpcUa.Runtime/Drivers/DriverHostActor.cs` (handler region ~line 482+)
+- Modify: `src/Server/ZB.MOM.WW.OtOpcUa.Runtime/Historian/HistorianAdapterActor.cs` (ctor handlers ~line 86)
+- Modify: `src/Server/ZB.MOM.WW.OtOpcUa.Runtime/ScriptedAlarms/ScriptedAlarmHostActor.cs` (ctor handlers ~line 172)
+- Test: `tests/Server/ZB.MOM.WW.OtOpcUa.Runtime.Tests/…` (new guard test; place beside the existing dead-letter-probe test — find it via `rg "AllDeadLetters" tests`)
+
+**Step 1 — Write the guard test (failing without the fix).** For at least `DriverHostActor`
+(the most-trafficked), subscribe a probe to `AllDeadLetters` on the EventStream, spin up the
+actor with its redundancy-topic subscription, publish a `PeerOpcUaProbeActor.OpcUaProbeResult`
+to the `RedundancyStateTopic`, and assert **no** `DeadLetter` wrapping an `OpcUaProbeResult`.
+(Mirror the Phase-B `AllDeadLetters`-probe idiom already in Runtime.Tests.) A combined test
+covering all three is fine if the harness makes that easy; otherwise the `DriverHostActor`
+case is the required guard and the other two are covered by inspection + build.
+
+**Step 2 — Add the drop to each actor.** Each already subscribes the redundancy-state topic in
+`PreStart` and imports `Akka.Cluster.Tools.PublishSubscribe`. Add, next to the existing
+`RedundancyStateChanged` / `SubscribeAck` handlers:
+```csharp
+// The redundancy-state topic also carries OpcUaProbeResult (published by OpcUaPublishActor's
+// peer-probes). We don't consume it here — drop it so it doesn't dead-letter. Matches
+// PeerProbeSupervisor / OpcUaPublishActor. (intentional no-op)
+Receive(_ => { });
+```
+- `HistorianAdapterActor`: add in the ctor near `Receive(_ => { });` (~line 87).
+- `ScriptedAlarmHostActor`: add in the ctor near the other `Receive<…>` registrations (~line 172).
+- `DriverHostActor`: add in the steady-state behaviour where `Receive<…>` handlers are registered
+ (the `Receive` handler — confirm it exists in each behaviour that is
+ active while subscribed; add the drop wherever `RedundancyStateChanged` is handled so the probe
+ result is dropped in the same behaviour(s)).
+ **Note:** if `DriverHostActor` uses `Become`/multiple behaviours, add the drop to every behaviour
+ that handles `RedundancyStateChanged`, else the probe still dead-letters in the others.
+
+**Step 3 — Test + build:**
+`dotnet test tests/Server/ZB.MOM.WW.OtOpcUa.Runtime.Tests --filter "FullyQualifiedName~ProbeResult"` → green;
+`dotnet build src/Server/ZB.MOM.WW.OtOpcUa.Runtime` → 0 errors.
+
+**Step 4 — Commit:**
+`git add src/Server/ZB.MOM.WW.OtOpcUa.Runtime/Drivers/DriverHostActor.cs src/Server/ZB.MOM.WW.OtOpcUa.Runtime/Historian/HistorianAdapterActor.cs src/Server/ZB.MOM.WW.OtOpcUa.Runtime/ScriptedAlarms/ScriptedAlarmHostActor.cs tests/Server/ZB.MOM.WW.OtOpcUa.Runtime.Tests/`
+then `git commit -m "fix(runtime): drop OpcUaProbeResult in redundancy-topic subscribers (no dead-letter)"`.
+
+---
+
+### Task 4: Reconcile + full build/test + live `/run` + finish
+
+**Classification:** standard (verification + integration review + finish)
+**Estimated implement time:** ~5 min + live run
+**Parallelizable with:** none (depends on T1, T2, T3)
+
+**Step 1 — Full build + solution test:**
+`dotnet build ZB.MOM.WW.OtOpcUa.slnx` → 0 errors;
+`dotnet test tests/Server/ZB.MOM.WW.OtOpcUa.AdminUI.Tests tests/Server/ZB.MOM.WW.OtOpcUa.Runtime.Tests` → green.
+
+**Step 2 — Final integration review** (code-reviewer subagent over `git diff master..HEAD`):
+confirm no Commons/proto/EF change, audit emitted on all cert paths (incl. failures), the
+`AuditEvent` shape matches the package, the drop handler is in every behaviour that subscribes
+the topic, and tests genuinely fail without the fix.
+
+**Step 3 — Live `/run` (agent-driven; docker-dev login is disabled).** Rebuild both central
+nodes to the branch (`docker compose -f docker-dev/docker-compose.yml up -d --build central-1
+central-2`); open the AdminUI Certificates page (`http://localhost:9200`), perform a Trust or
+Untrust (or seed a rejected cert first), and confirm a new `ConfigAuditLog` row exists
+(query the shared SQL `10.100.0.35,14330` ConfigDb: principal = the dev admin user,
+EventType = `Certificate:Trust`, Outcome = success). Confirm server logs show **no**
+`OpcUaProbeResult` dead-letter on either node. Capture the evidence.
+
+**Step 4 — Finish.** `git checkout master && git merge --ff-only feat/cert-audit-and-probe-tidy`
+(fast-forward; the branch is linear off master), then `git push`. Delete the feature branch.
+Update `pending.md`/`stillpending.md` (on-disk, never-staged) to record both items shipped.
diff --git a/docs/plans/2026-06-19-cert-audit-and-probe-deadletter-tidy.md.tasks.json b/docs/plans/2026-06-19-cert-audit-and-probe-deadletter-tidy.md.tasks.json
new file mode 100644
index 00000000..24fcaa37
--- /dev/null
+++ b/docs/plans/2026-06-19-cert-audit-and-probe-deadletter-tidy.md.tasks.json
@@ -0,0 +1,11 @@
+{
+ "planPath": "docs/plans/2026-06-19-cert-audit-and-probe-deadletter-tidy.md",
+ "executionState": "IN_PROGRESS",
+ "tasks": [
+ {"id": 1, "subject": "Task 1: Cert-audit core — ActorAuditWriter + CertAuditEvents factory + DI + unit tests", "classification": "standard", "status": "pending", "parallelizableWith": [3]},
+ {"id": 2, "subject": "Task 2: Wire audit into CertificateStoreManager + Certificates.razor + extend manager tests", "classification": "standard", "status": "pending", "blockedBy": [1]},
+ {"id": 3, "subject": "Task 3: OpcUaProbeResult dead-letter tidy — three actor drop handlers + guard test", "classification": "small", "status": "pending", "parallelizableWith": [1]},
+ {"id": 4, "subject": "Task 4: Reconcile + full build/test + live /run + finish (merge + push)", "classification": "standard", "status": "pending", "blockedBy": [1, 2, 3]}
+ ],
+ "lastUpdated": "2026-06-19"
+}