lmxopcua/docs/v2/implementation/exit-gate-phase-3.md

Phase 3 Exit Gate — Driver Fleet (reconstructed retroactively)

Status: CLOSED (reconstructed 2026-04-23). The original plan split the driver work across Phases 3 / 4 / 5 (Modbus alone → four PLC drivers → two specialty drivers). In execution, all seven non-Galaxy drivers shipped under one umbrella against Core.Abstractions + Core's generic driver-hosting machinery. This doc captures the closure retroactively; no forward work remains under these three original phase numbers.

Plan doc: none — phases 3/4/5 were intentionally not split out into separate plan docs once it was clear the capability-interface contract introduced in Phase 1 (Core.Abstractions — plan decision #4) was stable enough that each driver could land as its own stream rather than as a gated mini-phase. See docs/v2/plan.md §6 for the now-consolidated migration strategy.

Scope

All seven drivers in the v2 target list (Decision #5) minus Galaxy (closed separately under Phase 2). The Galaxy Proxy+Host+Shared split exited under exit-gate-phase-2-final.md; this gate does not re-cover it.

What shipped

Drivers

Driver	Project	Capability surface	Test projects
Modbus TCP	Driver.Modbus + Driver.Modbus.Cli	IDriver + ITagDiscovery + IReadable + IWritable + ISubscribable + IHostConnectivityProbe	Tests, IntegrationTests, Cli.Tests
AB CIP	Driver.AbCip + Driver.AbCip.Cli	all of the above + IPerCallHostResolver + IAlarmSource	Tests, IntegrationTests, Cli.Tests
AB Legacy (PCCC / DF1)	Driver.AbLegacy + Driver.AbLegacy.Cli	IDriver + IReadable + IWritable + ITagDiscovery + ISubscribable + IHostConnectivityProbe + IPerCallHostResolver	Tests, IntegrationTests, Cli.Tests
Siemens S7	Driver.S7 + Driver.S7.Cli	IDriver + ITagDiscovery + IReadable + IWritable + ISubscribable + IHostConnectivityProbe	Tests, IntegrationTests, Cli.Tests
Beckhoff TwinCAT (ADS)	Driver.TwinCAT + Driver.TwinCAT.Cli	IDriver + IReadable + IWritable + ITagDiscovery + ISubscribable + IHostConnectivityProbe + IPerCallHostResolver	Tests, IntegrationTests, Cli.Tests
FANUC FOCAS	Driver.FOCAS + Driver.FOCAS.Host + Driver.FOCAS.Shared + Driver.FOCAS.Cli	IDriver + IReadable + IWritable + ITagDiscovery + ISubscribable + IHostConnectivityProbe + IPerCallHostResolver; Tier-C out-of-process backend mirrors the Galaxy Proxy/Host split. Fwlib64FocasBackend shipped 2026-04-23 as the production backend (P/Invoke against Fwlib64.dll); Host retargeted from net48 x86 to net10.0-windows x64 at the same time.	Tests, Host.Tests, Shared.Tests, Cli.Tests
OPC UA Client (gateway)	Driver.OpcUaClient	IDriver + ITagDiscovery + IReadable + IWritable + ISubscribable + IHostConnectivityProbe + IAlarmSource + IHistoryProvider (richest surface in the fleet — it's bridging another UA server)	Tests, IntegrationTests

Supporting infrastructure

PR / Task	Summary
#248	DriverFactoryRegistry + DriverInstanceBootstrapper — central DB DriverInstance rows materialise into live IDriver instances at server startup.
#210	Modbus server-side factory + seed SQL (closed first child of umbrella #209).
#211 #212 #213	AB CIP / S7 / AB Legacy server-side factories + seed SQL.
#220 (FOCAS)	FOCAS factory wired into the bootstrap pipeline; Tier-C split (Driver.FOCAS.Host process launcher, named-pipe IPC, NSSM install scripts, post-mortem MMF) shipped across the five-PR series.
(this session)	TwinCAT factory wired in + Server project reference added; all seven driver factories now register uniformly in Server/Program.cs.
#249 #250 #251	Per-driver test-client CLI suite (otopcua-<driver>-cli) — shared lib + one CLI per driver for direct-to-PLC smoke testing independent of the server.
#253 + follow-ups	E2E CLI test scripts (scripts/e2e/test-<driver>.ps1) — five-stage bidirectional bridge + subscribe-sees-change assertions per driver, plus test-all.ps1 matrix runner.
(this session)	OPC UA Client e2e script shipped (test-opcuaclient.ps1, 8 stages) — the only driver that was missing an e2e script.

Docs

Per-driver test-fixture documentation:

• docs/drivers/Modbus-Test-Fixture.md
• docs/drivers/AbServer-Test-Fixture.md (covers AB CIP fixture)
• docs/drivers/AbLegacy-Test-Fixture.md
• docs/drivers/S7-Test-Fixture.md
• docs/drivers/TwinCAT-Test-Fixture.md
• docs/drivers/FOCAS-Test-Fixture.md
• docs/drivers/OpcUaClient-Test-Fixture.md

Driver-level ops docs:

• docs/Driver.Modbus.Cli.md, docs/Driver.AbCip.Cli.md, docs/Driver.AbLegacy.Cli.md, docs/Driver.S7.Cli.md, docs/Driver.TwinCAT.Cli.md, docs/Driver.FOCAS.Cli.md
• docs/v2/driver-specs.md — unified capability-matrix spec for all eight drivers (Galaxy + seven).

Compliance evidence

No dedicated phase-3-compliance.ps1 exists — scope was too broad to fit the single-script pattern that worked for Phases 6.x and 7. Verification instead takes the form of the per-driver test suites + e2e scripts:

• Unit tests — every driver has a Tests project with capability-interface contract tests; dotnet test tests/ZB.MOM.WW.OtOpcUa.Driver.*.Tests is green.
• Integration tests — Driver.*.IntegrationTests stands up Docker-hosted simulators (pymodbus, ab_server, python-snap7, opc-plc) at collection init and exercises real wire-level read/write/subscribe/probe per driver.
• CLI tests — Driver.*.Cli.Tests covers the per-driver test-client CLIs (#249–#251).
• E2E scripts — scripts/e2e/test-<driver>.ps1 covers the driver-CLI → PLC → OtOpcUa server → OPC UA client round-trip for all seven drivers + Galaxy; test-all.ps1 aggregates; README status section (rewritten this session) summarises live-boot evidence.
• Factory registration — all seven factories plus Galaxy register in src/ZB.MOM.WW.OtOpcUa.Server/Program.cs inside the DriverFactoryRegistry composition; the DriverInstanceBootstrapper can materialise any configured row.
• Seed SQL — #210–#213 provide per-driver Config DB seed scripts so a fresh Config DB is populatable without Admin UI interaction.

Live-boot verification

Recorded across the session-level tracking tasks:

Driver	Fixture	Stages	Tracking
Modbus	pymodbus (dl205 profile)	5/5	#209 exit gate; bidirectional + subscribe-sees-change added in #253 follow-ups
AB CIP	ab_server ControlLogix	5/5	#220
S7	python-snap7	5/5	#220
AB Legacy	ab_server SLC500 / MicroLogix / PLC-5 (requires /1,0 cip-path for Docker fixture)	5/5	#222 partial
OPC UA Client	opc-plc Docker fixture	5/8 (probe, remote read, forward bridge, subscribe, browse)	(this session)
TwinCAT	TCBSD VM @ 10.100.0.128 (AmsNetId 41.169.163.43.1.1) — real TwinCAT runtime under FreeBSD on ESXi; bypasses the Hyper-V/RTIME conflict that blocks XAR on this dev box	features validated	fixture is the TCBSD VM; TWINCAT_TRUST_WIRE=1 still gates the e2e script by default so unintentional runs against cold fixtures don't false-pass
FOCAS	Lab-rig CNC + Fwlib64.dll	—	deferred — Fwlib64FocasBackend shipped 2026-04-23; wire-level live-boot gated FOCAS_TRUST_WIRE=1, lab rig tracked under #222 follow-up
Galaxy	Live Galaxy + OtOpcUaGalaxyHost (this dev box)	7/7 (read / write / subscribe / alarms / history)	closed under Phase 2

Deferred to post-gate follow-ups

Items intentionally not blocking closure of this umbrella — each is hardware- dependent and tracked separately:

• FOCAS wire-level live-boot — test-focas.ps1 against a real CNC once Fwlib64.dll is on PATH and FOCAS_TRUST_WIRE=1 (#222 follow-up). The Fwlib64FocasBackend shipped 2026-04-23 — code exists, unit-tests green; only the live-CNC smoke test remains.
• FOCAS Fwlib64FocasBackend — CLOSED 2026-04-23. The production backend in src/ZB.MOM.WW.OtOpcUa.Driver.FOCAS.Host/Backend/Fwlib64FocasBackend.cs wraps FwlibFocasClient to fulfil IFocasBackend against the licensed Fwlib64.dll. Host project retargeted to net10.0-windows x64. Default when OTOPCUA_FOCAS_BACKEND is unset. 6 new backend tests green. Only wire-level live-boot against real hardware remains — see item above.
• OPC UA Client stages 5/7/8 — reverse-bridge, alarm, history stages are opt-in via sidecar NodeId params because opc-plc's default image has no writable nodes and doesn't historize. Against a richer upstream (Prosys, UA Expert sample server) all eight stages can run.

Completion checklist

• Modbus driver shipped + unit + integration + CLI tests green
• AB CIP driver shipped + tests green + live-boot 5/5
• AB Legacy driver shipped + tests green + live-boot 5/5
• S7 driver shipped + tests green + live-boot 5/5
• TwinCAT driver shipped + tests green + features validated against the TCBSD VM virtual-PLC fixture
• FOCAS driver shipped (Tier-C split) + tests green (wire-live deferred)
• OPC UA Client driver shipped + tests green + live-boot 5/8
• DriverFactoryRegistry + DriverInstanceBootstrapper shipped
• All seven factories registered in Server/Program.cs
• Per-driver test-client CLI suite shipped
• E2E test scripts shipped + test-all.ps1 aggregator green
• Per-driver test-fixture docs present
• docs/v2/driver-specs.md unified capability spec present
• scripts/e2e/README.md status section reflects current live-boot matrix
• Exit gate doc checked in (this file)
• TwinCAT validated against the TCBSD VM virtual-PLC fixture — TWINCAT_TRUST_WIRE=1 + e2e script still gated by default to prevent false-pass against cold fixtures
• FOCAS lab-rig follow-up filed + tracked (#222)

Why no compliance script

The Phases 6.1/6.2/6.3/6.4/7 pattern of a single phase-N-compliance.ps1 worked because each of those phases touched a narrow slice of server-side runtime. A "phase-3-compliance.ps1" would have had to boot seven simulators, configure seven DriverInstance rows, and run seven e2e scripts — which is exactly what scripts/e2e/test-all.ps1 already does. The aggregate runner

• its README is the compliance artefact for this umbrella.