Production IHostProcessLauncher (ProcessHostLauncher.cs): Process.Start spawns OtOpcUa.Driver.FOCAS.Host.exe with OTOPCUA_FOCAS_PIPE / OTOPCUA_ALLOWED_SID / OTOPCUA_FOCAS_SECRET / OTOPCUA_FOCAS_BACKEND in the environment (supervisor-owned, never disk), polls FocasIpcClient.ConnectAsync at 250ms cadence until the pipe is up or the Host exits or the ConnectTimeout deadline passes, then wraps the connected client in an IpcFocasClient. TerminateAsync kills the entire process tree + disposes the IPC stream. ProcessHostLauncherOptions carries HostExePath + PipeName + AllowedSid plus optional SharedSecret (auto-generated from a GUID when omitted so install scripts don't have to), Arguments, Backend (fwlib32/fake/unconfigured default-unconfigured), ConnectTimeout (15s), and Series for CNC pre-flight. Post-mortem MMF (Host/Stability/PostMortemMmf.cs + Proxy/Supervisor/PostMortemReader.cs): ring-buffer of the last ~1000 IPC operations written by the Host into a memory-mapped file. On a Host crash the supervisor reads the MMF — which survives process death — to see what was in flight. File format: 16-byte header [magic 'OFPC' (0x4F465043) | version | capacity | writeIndex] + N × 256-byte entries [8-byte UTC unix ms | 8-byte opKind | 240-byte UTF-8 message + null terminator]. Magic distinguishes FOCAS MMFs from the Galaxy MMFs that ship the same format shape. Writer is single-producer (Host) with a lock_writeGate; reader is multi-consumer (Proxy + any diagnostic tool) using a separate MemoryMappedFile handle. NSSM install wrappers (scripts/install/Install-FocasHost.ps1 + Uninstall-FocasHost.ps1): idempotent service registration for OtOpcUaFocasHost. Resolves SID from the ServiceAccount, generates a fresh shared secret per install if not supplied, stages OTOPCUA_FOCAS_PIPE/SID/SECRET/BACKEND in AppEnvironmentExtra so they never hit disk, rotates 10MB stdout/stderr logs under %ProgramData%\OtOpcUa, DependOnService=OtOpcUa so startup order is deterministic. Backend selector defaults to unconfigured so a fresh install doesn't accidentally load a half-configured Fwlib32.dll on first start. Tests (7 new, 2 files): PostMortemMmfTests.cs in FOCAS.Host.Tests — round-trip write+read preserves order + content, ring-buffer wraps at capacity (writes 10 entries to a 3-slot buffer, asserts only op-7/8/9 survive in FIFO order), message truncation at the 240-byte cap is null-terminated + non-overflowing, reopening an existing file preserves entries. PostMortemReaderCompatibilityTests.cs in FOCAS.Tests — hand-writes a file in the exact host format (magic/entry layout) + asserts the Proxy reader decodes with correct ring-walk ordering when writeIndex != 0, empty-return on missing file + magic mismatch. Keeps the two codebases in format-lockstep without the net10 test project referencing the net48 Host assembly. Docs updated: docs/v2/implementation/focas-isolation-plan.md promoted from DRAFT to PRs A-E shipped status with per-PR citations + post-ship test counts (189 + 24 + 13 = 226 FOCAS-family tests green). docs/drivers/FOCAS-Test-Fixture.md §5 updated from "architecture scoped but not implemented" to listing the shipped components with the FwlibHostedBackend gap explicitly labeled as hardware-gated. Install-FocasHost.ps1 documents the OTOPCUA_FOCAS_BACKEND selector + points at docs/v2/focas-deployment.md for Fwlib32.dll licensing. What ISN'T in this PR: (1) the real FwlibHostedBackend implementing IFocasBackend with the P/Invoke — requires either a CNC on the bench or a licensed FANUC developer kit to validate, tracked under #220 as a single follow-up task; (2) Admin /hosts surface integration for FOCAS runtime status — Galaxy Tier-C already has the shape, FOCAS can slot in when someone wires ObservedCrashes/StickyAlertActive/BackoffAttempt to the FleetStatusHub; (3) a full integration test that actually spawns a real FOCAS Host process — ProcessHostLauncher is tested via its contract + the MMF is tested via round-trip, but no test spins up the real exe (the Galaxy Tier-C tests do this, but the FOCAS equivalent adds no new coverage over what's already in place). Total FOCAS-family tests green after this PR: 189 driver + 24 Shared + 13 Host = 226. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Drivers
OtOpcUa is a multi-driver OPC UA server. The Core (ZB.MOM.WW.OtOpcUa.Core + Core.Abstractions + Server) owns the OPC UA stack, address space, session/security/subscription machinery, resilience pipeline, and namespace kinds (Equipment + SystemPlatform). Drivers plug in through capability interfaces defined in src/ZB.MOM.WW.OtOpcUa.Core.Abstractions/:
IDriver— lifecycle (InitializeAsync,ReinitializeAsync,ShutdownAsync,GetHealth)IReadable/IWritable— one-shot reads and writesITagDiscovery— address-space enumerationISubscribable— driver-pushed data-change streamsIHostConnectivityProbe— per-host reachability eventsIPerCallHostResolver— multi-host drivers that route each call to a target endpoint at dispatch timeIAlarmSource— driver-emitted OPC UA A&C eventsIHistoryProvider— raw / processed / at-time / events HistoryRead (see HistoricalDataAccess.md)IRediscoverable— driver-initiated address-space rebuild notifications
Each driver opts into only the capabilities it supports. Every async capability call at the Server dispatch layer goes through CapabilityInvoker (Core/Resilience/CapabilityInvoker.cs), which wraps it in a Polly pipeline keyed on (DriverInstanceId, HostName, DriverCapability). The OTOPCUA0001 analyzer enforces the wrap at build time. Drivers themselves never depend on Polly; they just implement the capability interface and let the Core wrap it.
Driver type metadata is registered at startup in DriverTypeRegistry (src/ZB.MOM.WW.OtOpcUa.Core.Abstractions/DriverTypeRegistry.cs). The registry records each type's allowed namespace kinds (Equipment / SystemPlatform / Simulated), its JSON Schema for DriverConfig / DeviceConfig / TagConfig columns, and its stability tier per docs/v2/driver-stability.md.
Ground-truth driver list
| Driver | Project path | Tier | Wire / library | Capabilities | Notable quirk |
|---|---|---|---|---|---|
| Galaxy | Driver.Galaxy.{Shared, Host, Proxy} |
C | MXAccess COM + aahClientManaged + SqlClient |
IDriver, ITagDiscovery, IReadable, IWritable, ISubscribable, IAlarmSource, IHistoryProvider, IRediscoverable, IHostConnectivityProbe | Out-of-process — Host is its own Windows service (.NET 4.8 x86 for the COM bitness constraint); Proxy talks to Host over a named pipe |
| Modbus TCP | Driver.Modbus |
A | NModbus-derived in-house client | IDriver, ITagDiscovery, IReadable, IWritable, ISubscribable, IHostConnectivityProbe | Polled subscriptions via the shared PollGroupEngine. DL205 PLCs are covered by AddressFormat=DL205 (octal V/X/Y/C/T/CT translation) — no separate driver |
| Siemens S7 | Driver.S7 |
A | S7netplus | IDriver, ITagDiscovery, IReadable, IWritable, ISubscribable, IHostConnectivityProbe | Single S7netplus Plc instance per PLC serialized with SemaphoreSlim — the S7 CPU's comm mailbox is scanned at most once per cycle, so parallel reads don't help |
| AB CIP | Driver.AbCip |
A | libplctag CIP | IDriver, ITagDiscovery, IReadable, IWritable, ISubscribable, IHostConnectivityProbe, IPerCallHostResolver | ControlLogix / CompactLogix. Tag discovery uses the @tags walker to enumerate controller-scoped + program-scoped symbols; UDT member resolution via the UDT template reader |
| AB Legacy | Driver.AbLegacy |
A | libplctag PCCC | IDriver, ITagDiscovery, IReadable, IWritable, ISubscribable, IHostConnectivityProbe, IPerCallHostResolver | SLC 500 / MicroLogix. File-based addressing (N7:0, F8:0) — no symbol table, tag list is user-authored in the config DB |
| TwinCAT | Driver.TwinCAT |
B | Beckhoff TwinCAT.Ads (TcAdsClient) |
IDriver, ITagDiscovery, IReadable, IWritable, ISubscribable, IHostConnectivityProbe, IPerCallHostResolver | The only native-notification driver outside Galaxy — ADS delivers ValueChangedCallback events the driver forwards straight to ISubscribable.OnDataChange without polling. Symbol tree uploaded via SymbolLoaderFactory |
| FOCAS | Driver.FOCAS |
C | FANUC FOCAS2 (Fwlib32.dll P/Invoke) |
IDriver, ITagDiscovery, IReadable, IWritable, ISubscribable, IHostConnectivityProbe, IPerCallHostResolver | Tier C — FOCAS DLL has crash modes that warrant process isolation. CNC-shaped data model (axes, spindle, PMC, macros, alarms) not a flat tag map |
| OPC UA Client | Driver.OpcUaClient |
B | OPCFoundation Opc.Ua.Client |
IDriver, ITagDiscovery, IReadable, IWritable, ISubscribable, IAlarmSource, IHistoryProvider, IHostConnectivityProbe | Gateway/aggregation driver. Opens a single Session against a remote OPC UA server and re-exposes its address space. Owns its own ApplicationConfiguration (distinct from Client.Shared) because it's always-on with keep-alive + TransferSubscriptions across SDK reconnect, not an interactive CLI |
Per-driver documentation
-
Galaxy has its own docs in this folder because the out-of-process architecture + MXAccess COM rules + Galaxy Repository SQL + Historian + runtime probe manager don't fit a single table row:
- Galaxy.md — COM bridge, STA pump, IPC, runtime probes
- Galaxy-Repository.md — ZB SQL reader,
LocalPlatformscope filter, change detection
-
All other drivers share a single per-driver specification in docs/v2/driver-specs.md — addressing, data-type maps, connection settings, and quirks live there. That file is the authoritative per-driver reference; this index points at it rather than duplicating.
Test-fixture coverage maps
Each driver has a dedicated fixture doc that lays out what the integration / unit harness actually covers vs. what's trusted from field deployments. Read the relevant one before claiming "green suite = production-ready" for a driver.
- AB CIP — Dockerized
ab_server(multi-stage build from libplctag source); atomic-read smoke across 4 families; UDT / ALMD / family quirks unit-only - Modbus — Dockerized
pymodbus+ per-family JSON profiles (4 compose profiles); best-covered driver, gaps are error-path-shaped - Siemens S7 — Dockerized
python-snap7server; DB/MB read + write round-trip verified end-to-end on:1102 - AB Legacy — Docker scaffold via
ab_serverPCCC mode (task #224); wire-level round-trip currently blocked by ab_server's PCCC coverage gap, docs call out RSEmulate 500 + lab-rig resolution paths - TwinCAT — XAR-VM integration scaffolding (task #221); three smoke tests skip when VM unreachable. Unit via
FakeTwinCATClientwith native-notification harness - FOCAS — no integration fixture, unit-only via
FakeFocasClient; Tier C out-of-process isolation scoped but not shipped - OPC UA Client — no integration fixture, unit-only via mocked
Session; loopback against this repo's own server is the obvious next step - Galaxy — richest harness: E2E Host subprocess + ZB SQL live-smoke + MXAccess opt-in
Related cross-driver docs
- HistoricalDataAccess.md —
IHistoryProviderdispatch, aggregate mapping, continuation points. The Galaxy driver's Aveva Historian implementation is the first; OPC UA Client forwards to the upstream server; other drivers do not implement the interface and returnBadHistoryOperationUnsupported. - AlarmTracking.md —
IAlarmSourceevent model and filtering. - Subscriptions.md — how the Server multiplexes subscriptions onto
ISubscribable.OnDataChange. - docs/v2/driver-stability.md — tier system (A / B / C), shared
CapabilityPolicydefaults per tier × capability,MemoryTrackinghybrid formula, and process-level recycle rules. - docs/v2/plan.md — authoritative vision, architecture decisions, migration strategy.