Files
lmxopcua/docs
Joseph Doherty f2049a31d0 docs(localdb-phase2): pre-answer Task 0's STOP condition — it does not fire
Phase 2's recon carries a STOP condition: a BLOB payload column in the legacy
alarm store-and-forward table could not be registered for replication and would
have to become base64 TEXT, sized against the chunk guidance. Resolved ahead of
execution so the answer survives into the Phase 2 session:

- No BLOB. All 8 columns are TEXT/INTEGER; the payload is PayloadJson TEXT NOT
  NULL. No base64 conversion, no chunk sizing needed.
- The executed DDL (SqliteStoreAndForwardSink.cs:657-667) matches the class
  doc-comment at :17-26 exactly — checked because a doc comment is not evidence.
- Payload is bounded by shape: a serialized AlarmHistorianEvent is 10 scalar
  fields, no collections or nesting, so realistic worst case is low single-digit
  KB against a 171 KB guidance.
- The PK IS autoincrement, confirming the plan's prediction that the migrator
  must mint deterministic mig-{node}-{legacyId} ids and the new table needs a
  TEXT GUID PK.
- Also captured for reuse: the drain's covering index (DeadLettered, RowId), and
  the exact legacy column list the migrator's pragma_table_info intersection
  check compares against.

Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
2026-07-21 03:46:56 -04:00
..

OtOpcUa documentation

Two tiers of documentation live here:

  • Current reference at the top level (docs/*.md) — describes what's shipped today. Start here for operator + integrator reference.
  • Implementation history + design notes at docs/v2/*.md — the authoritative plan + decision log the current reference is built from. Start here when you need the why behind an architectural choice, or when a top-level doc says "see plan.md § X".

The project was originally called LmxOpcUa (a single-driver Galaxy/MXAccess OPC UA server) and has since become OtOpcUa, a multi-driver OPC UA server platform. Any lingering LmxOpcUa-string in a path you see in docs is a deliberate residual (executable name lmxopcua-cli, client PKI folder {LocalAppData}/LmxOpcUaClient/) — fixing those requires migration shims + is tracked as follow-ups.

Platform overview

v2 (2026-05-26): the separate OtOpcUa.Server + OtOpcUa.Admin services fused into a single role-gated OtOpcUa.Host binary, joined by an Akka.NET cluster. See v2 design for the architectural decision.

  • Core owns shared abstractions (driver capability contracts, scripting, virtual tags, alarm historian).
  • Drivers plug in via capability interfaces in ZB.MOM.WW.OtOpcUa.Core.Abstractions: IDriver, IReadable, IWritable, ITagDiscovery, ISubscribable, IHostConnectivityProbe, IAlarmSource, IHistoryProvider, IPerCallHostResolver. Each driver opts into whichever it supports.
  • Host (src/Server/ZB.MOM.WW.OtOpcUa.Host) is the single fused binary (.NET 10, AnyCPU). OTOPCUA_ROLES env decides what to mount: admin (Blazor + control-plane singletons), driver (OPC UA endpoint + per-node actors), or both. See ServiceHosting.md.
  • Cluster + ControlPlane + Runtime + AdminUI + Security sit between Core and Host. The cluster glues per-node actors into one logical fleet; the control-plane singletons (deploy coordinator, audit writer, redundancy state) live on the admin role-leader. See Redundancy.md.
  • The Galaxy driver still reaches MXAccess via gRPC to a separately-installed mxaccessgw sidecar (sibling repo).

Where to find what

Architecture + data-path reference

Doc Covers
OpcUaServer.md Top-level server architecture — Core, driver dispatch, Config DB, generations
AddressSpace.md GenericDriverNodeManager + ITagDiscovery + IAddressSpaceBuilder
ReadWriteOperations.md OPC UA Read/Write → CapabilityInvokerIReadable/IWritable
DriverLifecycle.md Server-side driver lifecycle + infrastructure contracts (IDriverFactory, IDriverProbe, IDriverSupervisor, IDriverHealthPublisher, IDriverConfigEditor, IHistorianDataSource) + the Commons library
Subscriptions.md Monitored items → ISubscribable + per-driver subscription refcount (v1 archive)
AlarmTracking.md IAlarmSource + AlarmSurfaceInvoker + OPC UA alarm conditions — native Galaxy alarms end-to-end (live)
AlarmTracking.md Original alarm-tracking write-up (v1 archive)
AlarmHistorian.md Core.AlarmHistorian store-and-forward SQLite sink — SqliteStoreAndForwardSink, IAlarmHistorianWriter, dead-letter/retry/eviction
DataTypeMapping.md Per-driver DriverAttributeInfo → OPC UA variable types (v1 archive — live mapping is in src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Galaxy/Browse/DataTypeMap.cs)
IncrementalSync.md Address-space rebuild on redeploy + sp_ComputeGenerationDiff
HistoricalDataAccess.md IHistoryProvider as a per-driver optional capability (v1 archive)
VirtualTags.md Core.Scripting + Core.VirtualTags — Roslyn script sandbox, engine, dispatch alongside driver tags
ScriptEditor.md Monaco script editor — Roslyn-backed IntelliSense (completions, diagnostics, hover, tag-path) for C# virtual-tag scripts; AdminUI/ScriptAnalysis/ backend
ScriptedAlarms.md Core.ScriptedAlarms — script-predicate IAlarmSource + Part 9 state machine

One Core subsystem is shipped without a dedicated top-level doc; see the section in the linked doc:

Project See
Analyzers (Roslyn OTOPCUA0001) security.md § OTOPCUA0001 Analyzer

Drivers

Doc Covers
drivers/README.md Index of the eight shipped drivers + capability matrix
drivers/Galaxy.md Galaxy driver — in-process gRPC client to the mxaccessgw sidecar
v1/drivers/Galaxy-Repository.md Galaxy-specific discovery via the ZB SQL database (v1 archive — the gateway owns this path now)

For Modbus / S7 / AB CIP / AB Legacy / TwinCAT / FOCAS / OPC UA Client specifics, see v2/driver-specs.md.

Operational

Doc Covers
Configuration.md Live appsettings + environment-variable reference (current state)
Configuration.md appsettings bootstrap + Config DB + Admin UI draft/publish (v1 archive — OTOPCUA_GALAXY_* env vars now live in mxaccessgw config)
Uns.md The global /uns master tree — manage Area/Line/Equipment/Tag/VirtualTag fleet-wide; replaces the per-cluster UNS/Equipment/Tags tabs
security.md Transport security profiles, LDAP auth, ACL trie, role grants, OTOPCUA0001 analyzer
Redundancy.md RedundancyCoordinator, ServiceLevelCalculator, apply-lease, Prometheus metrics
Reservations.md Fleet-wide ZTag / SAPID external-ID reservations — publish-time claim, release flow
ServiceHosting.md Single fused OtOpcUa.Host binary install/uninstall with OTOPCUA_ROLES gating; the historian backend is the external HistorianGateway
StatusDashboard.md Pointer — superseded by v2/admin-ui.md

Client tooling

Doc Covers
Client.CLI.md otopcua-cli — OPC UA command-line client
Client.UI.md Avalonia desktop client
DriverClis.md Driver test-client CLIs — index + shared commands
Driver.Modbus.Cli.md otopcua-modbus-cli — Modbus-TCP
Driver.AbCip.Cli.md otopcua-abcip-cli — ControlLogix / CompactLogix / Micro800 / GuardLogix
Driver.AbLegacy.Cli.md otopcua-ablegacy-cli — SLC / MicroLogix / PLC-5 (PCCC)
Driver.S7.Cli.md otopcua-s7-cli — Siemens S7-300 / S7-400 / S7-1200 / S7-1500
Driver.TwinCAT.Cli.md otopcua-twincat-cli — Beckhoff TwinCAT 2/3 ADS
Driver.FOCAS.Cli.md otopcua-focas-cli — Fanuc FOCAS/2 CNC

Requirements

Doc Covers
reqs/HighLevelReqs.md HLRs — numbered system-level requirements
reqs/OpcUaServerReqs.md OPC UA server-layer reqs
v1/reqs/ServiceHostReqs.md Per-process hosting reqs (v1 archive — only OtOpcUa server hosting remains in scope post-PR-7.2)
reqs/ClientRequirements.md Client CLI + UI reqs
v1/reqs/GalaxyRepositoryReqs.md Galaxy-scoped repository reqs (v1 archive — owned by mxaccessgw today)
v1/reqs/MxAccessClientReqs.md Galaxy-scoped MXAccess reqs (v1 archive — owned by mxaccessgw today)
reqs/StatusDashboardReqs.md Pointer — superseded by Admin UI

Implementation history (docs/v2/)

Design decisions + phase plans + execution notes. Load-bearing cross-references from the top-level docs:

v1 archive

The v1 in-process MXAccess architecture (Galaxy.Host + Galaxy.Proxy + Galaxy.Shared, .NET 4.8 x86 COM, the OtOpcUaGalaxyHost Windows service) was retired in PR 7.2 (2026-04-30, commit ae7106d). Docs that described that shape are kept under v1/ as historical record — see v1/README.md for the index.