# LMX Galaxy bridge — remaining follow-ups

State after PR 19: the Galaxy driver is functionally at v1 parity through the
`IDriver` abstraction; the OPC UA server runs with LDAP-authenticated
Basic256Sha256 endpoints and alarms are observable through
`AlarmConditionState.ReportEvent`. The items below are what remains LMX-
specific before the stack can fully replace the v1 deployment, in
rough priority order.

## 1. Proxy-side `IHistoryProvider` for `ReadAtTime` / `ReadEvents` — **DONE (PRs 35 + 38)**

PR 35 extended `IHistoryProvider` with `ReadAtTimeAsync` + `ReadEventsAsync`
(default throwing implementations so existing impls keep compiling), added the
`HistoricalEvent` + `HistoricalEventsResult` records to `Core.Abstractions`,
and implemented both methods in `GalaxyProxyDriver` on top of the PR 10 / PR 11
IPC messages.

PR 38 wired the OPC UA HistoryRead service-handler through
`DriverNodeManager` by overriding `CustomNodeManager2`'s four per-kind hooks —
`HistoryReadRawModified` / `HistoryReadProcessed` / `HistoryReadAtTime` /
`HistoryReadEvents`. Each walks `nodesToProcess`, resolves the driver-side
full reference from `NodeId.Identifier`, dispatches to the right
`IHistoryProvider` method, and populates the paired results + errors lists
(both must be set — the MasterNodeManager merges them and a Good result with
an unset error slot serializes as `BadHistoryOperationUnsupported` on the
wire). Historized variables gain `AccessLevels.HistoryRead` so the stack
dispatches; the driver root folder gains `EventNotifiers.HistoryRead` so
`HistoryReadEvents` can target it.

Aggregate translation uses a small `MapAggregate` helper that handles
`Average` / `Minimum` / `Maximum` / `Total` / `Count` (the enum surface the
driver exposes) and returns null for unsupported aggregates so the handler
can surface `BadAggregateNotSupported`. Raw+Processed+AtTime wrap driver
samples as `HistoryData` in an `ExtensionObject`; Events emits a
`HistoryEvent` with the standard BaseEventType field list (EventId /
SourceName / Message / Severity / Time / ReceiveTime) — custom
`SelectClause` evaluation is an explicit follow-up.

**Tests**:

- `DriverNodeManagerHistoryMappingTests` — 12 unit cases pinning
  `MapAggregate`, `BuildHistoryData`, `BuildHistoryEvent`, `ToDataValue`.
- `HistoryReadIntegrationTests` — 5 end-to-end cases drive a real OPC UA
  client (`Session.HistoryRead`) against a fake `IHistoryProvider` driver
  through the running stack. Covers raw round-trip, processed with Average
  aggregate, unsupported aggregate → `BadAggregateNotSupported`, at-time
  timestamp forwarding, and events field-list shape.

**Deferred**:
- Continuation-point plumbing via `Session.Save/RestoreHistoryContinuationPoint`.
  Driver returns null continuations today so the pass-through is fine.
- Per-`SelectClause` evaluation in HistoryReadEvents — clients that send a
  custom field selection currently get the standard BaseEventType layout.

## 2. Write-gating by role — **DONE (PR 26)**

Landed in PR 26. `WriteAuthzPolicy` in `Server/Security/` maps
`SecurityClassification` → required role (`FreeAccess` → no role required,
`Operate`/`SecuredWrite` → `WriteOperate`, `Tune` → `WriteTune`,
`Configure`/`VerifiedWrite` → `WriteConfigure`, `ViewOnly` → deny regardless).
`DriverNodeManager` caches the classification per variable during discovery and
checks the session's roles (via `IRoleBearer`) in `OnWriteValue` before calling
`IWritable.WriteAsync`. Roles do not cascade — a session with `WriteOperate`
can't write a `Tune` attribute unless it also carries `WriteTune`.

See `feedback_acl_at_server_layer.md` in memory for the architectural directive
that authz stays at the server layer and never delegates to driver-specific auth.

## 3. Admin UI client-cert trust management — **DONE (PR 28)**

PR 28 shipped `/certificates` in the Admin UI. `CertTrustService` reads the OPC
UA server's PKI store root (`OpcUaServerOptions.PkiStoreRoot` — default
`%ProgramData%\OtOpcUa\pki`) and lists rejected + trusted certs by parsing the
`.der` files directly, so it has no `Opc.Ua` dependency and runs on any
Admin host that can reach the shared PKI directory.

Operator actions: Trust (moves `rejected/certs/*.der` → `trusted/certs/*.der`),
Delete rejected, Revoke trust. The OPC UA stack re-reads the trusted store on
each new client handshake, so no explicit reload signal is needed —
operators retry the rejected client's connection after trusting.

Deferred: flipping `AutoAcceptUntrustedClientCertificates` to `false` as the
deployment default. That's a production-hardening config change, not a code
gap — the Admin UI is now ready to be the trust gate.

## 4. Live-LDAP integration test — **DONE (PR 31)**

PR 31 shipped `Server.Tests/LdapUserAuthenticatorLiveTests.cs` — 6 live-bind
tests against the dev GLAuth instance at `localhost:3893`, skipped cleanly
when the port is unreachable. Covers: valid bind, wrong password, unknown
user, empty credentials, single-group → WriteOperate mapping, multi-group
admin user surfacing all mapped roles.

Also added `UserNameAttribute` to `LdapOptions` (default `uid` for RFC 2307
compat) so Active Directory deployments can configure `sAMAccountName` /
`userPrincipalName` without code changes. `LdapUserAuthenticatorAdCompatTests`
(5 unit guards) pins the AD-shape DN parsing + filter escape behaviors. See
`docs/security.md` §"Active Directory configuration" for the AD appsettings
snippet.

Deferred: asserting `session.Identity` end-to-end on the server side (i.e.
drive a full OPC UA session with username/password, then read an
`IHostConnectivityProbe`-style "whoami" node to verify the role surfaced).
That needs a test-only address-space node and is a separate PR.

## 5. Full Galaxy live-service smoke test against the merged v2 stack — **IN PROGRESS (PRs 36 + 37)**

PR 36 shipped the prerequisites helper (`AvevaPrerequisites`) that probes
every dependency a live smoke test needs and produces actionable skip
messages.

PR 37 shipped the live-stack smoke test project structure:
`tests/Driver.Galaxy.Proxy.Tests/LiveStack/` with `LiveStackFixture` (connects
to the *already-running* `OtOpcUaGalaxyHost` Windows service via named pipe;
never spawns the Host process) and `LiveStackSmokeTests` covering:

- Fixture initializes successfully (IPC handshake succeeds end-to-end).
- Driver reports `DriverState.Healthy` post-handshake.
- `DiscoverAsync` returns at least one variable from the live Galaxy.
- `GetHostStatuses` reports at least one Platform/AppEngine host.
- `ReadAsync` on a discovered variable round-trips through
  Proxy → Host pipe → MXAccess → back without a BadInternalError.

Shared secret + pipe name resolve from `OTOPCUA_GALAXY_SECRET` /
`OTOPCUA_GALAXY_PIPE` env vars, falling back to reading the service's
registry-stored Environment values (requires elevated test host).

**PR 40** added the write + subscribe facts targeting
`DelmiaReceiver_001.TestAttribute` (the writable Boolean UDA the dev Galaxy
ships under TestMachine_001) — write-then-read with a 5s scan-window poll +
restore-on-finally, and subscribe-then-write asserting both an initial-value
OnDataChange and a post-write OnDataChange. PR 39 added the elevated-shell
short-circuit so a developer running from an admin window gets an actionable
skip instead of `UnauthorizedAccessException`.

**Run the live tests** (from a NORMAL non-admin PowerShell):

```powershell
$env:OTOPCUA_GALAXY_SECRET = Get-Content C:\Users\dohertj2\Desktop\lmxopcua\.local\galaxy-host-secret.txt
cd C:\Users\dohertj2\Desktop\lmxopcua
dotnet test tests\ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Proxy.Tests --filter "FullyQualifiedName~LiveStackSmokeTests"
```

Expected: 7/7 pass against the running `OtOpcUaGalaxyHost` service.

**Remaining for #5 in production-grade form**:
- Confirm the suite passes from a non-elevated shell (operator action).
- Add similar facts for an alarm-source attribute once `TestMachine_001` (or
  a sibling) carries a deployed alarm condition — the current dev Galaxy's
  TestAttribute isn't alarm-flagged.

## 6. Second driver instance on the same server — **DONE (PR 32)**

`Server.Tests/MultipleDriverInstancesIntegrationTests.cs` registers two
drivers with distinct `DriverInstanceId`s on one `DriverHost`, spins up the
full OPC UA server, and asserts three behaviors: (1) each driver's namespace
URI (`urn:OtOpcUa:{id}`) resolves to a distinct index in the client's
NamespaceUris, (2) browsing one subtree returns that driver's folder and
does NOT leak the other driver's folder, (3) reads route to the correct
driver — the alpha instance returns 42 while beta returns 99, so a misroute
would surface at the assertion layer.

Deferred: the alarm-event multi-driver parity case (two drivers each raising
a `GalaxyAlarmEvent`, assert each condition lands on its owning instance's
condition node). Alarm tracking already has its own integration test
(`AlarmSubscription*`); the multi-driver alarm case would need a stub
`IAlarmSource` that's worth its own focused PR.

## 7. Host-status per-AppEngine granularity → Admin UI dashboard — **DONE (PRs 33 + 34)**

**PR 33** landed the data layer: `DriverHostStatus` entity + migration with
composite key `(NodeId, DriverInstanceId, HostName)` and two query-supporting
indexes (per-cluster drill-down on `NodeId`, stale-row detection on
`LastSeenUtc`).

**PR 34** wired the publisher + consumer. `HostStatusPublisher` is a
`BackgroundService` in the Server process that walks every registered
`IHostConnectivityProbe`-capable driver every 10s, calls
`GetHostStatuses()`, and upserts rows (`LastSeenUtc` advances each tick;
`State` + `StateChangedUtc` update on transitions). Admin UI `/hosts` page
groups by cluster, shows four summary cards (Hosts / Running / Stale /
Faulted), and flags rows whose `LastSeenUtc` is older than 30s as Stale so
operators see crashed Servers without waiting for a state change.

Deferred as follow-ups:

- Event-driven push (subscribe to `OnHostStatusChanged` per driver for
  sub-heartbeat latency). Adds DriverHost lifecycle-event plumbing;
  10s polling is fine for operator-scale use.
- Failure-count column — needs the publisher to track a transition history
  per host, not just current-state.
- SignalR fan-out to the Admin page (currently the page polls the DB, not
  a hub). The DB-polled version is fine at current cadence but a hub push
  would eliminate the 10s race where a new row sits in the DB before the
  Admin page notices.