Both VirtualTagEngine.Load and ScriptedAlarmEngine.LoadAsync were calling
ScriptEvaluator.Compile directly, bypassing CompiledScriptCache. The
Core.Scripting-008 collectible-ALC fix wired Dispose only through the cache's
Clear()/Dispose(), so the per-publish accretion the -008 fix was meant to
eliminate was still in effect on the actual production path — the headline
'no more restarts needed' guarantee wasn't delivered.
Resolution:
- VirtualTagEngine + ScriptedAlarmEngine each gained a private
CompiledScriptCache<TContext, TResult> instance.
- Both Load methods now call _compileCache.GetOrCompile(source).
- Publish-replace path: _compileCache.Clear() runs alongside the existing
_tags / _alarms clears so the prior generation's ALCs are disposed
before recompile.
- Engine Dispose now calls _compileCache.Dispose() so shutdown actually
releases the emitted assemblies.
Side-fix in CompiledScriptCache: Dispose() set _disposed=true then called
Clear(), but Clear() had a pre-existing 'if (_disposed) return' guard that
aborted the drain unconditionally — making the Dispose-triggered cleanup a
silent no-op. Removed the disposed-guard on Clear() (clearing an empty/
cleared cache is idempotent).
Side-fix in ScriptedAlarmEngine.Dispose: cleared _alarms AFTER the
Task.WhenAll drain. The drain guarantees no background callback is mid-
flight, so clearing is safe. Previously _alarms was deliberately NOT
cleared on Dispose (per Core.ScriptedAlarms-005), but that left the
AlarmState records holding TimedScriptEvaluator → ScriptEvaluator → delegate
references that rooted the emitted assemblies, defeating the cache's
Dispose work on the engine side.
Regression tests:
- VirtualTagEngineTests.Dispose_unloads_compiled_script_assembly
- ScriptedAlarmEngineTests.Dispose_unloads_compiled_predicate_assembly
Both use WeakReference + bounded GC.Collect() to prove the emitted
assembly is reclaimable after engine.Dispose(). The alarms test had to
be synchronous (not 'async Task<WeakReference>') because async state
machines capture locals as state-struct fields, keeping them alive past
the method's apparent end and defeating GC.
Verification:
- Core.Scripting.Tests: 104/104 (unchanged).
- VirtualTags.Tests: 57/57 (was 56 — +1 unload test).
- ScriptedAlarms.Tests: 67/67 (was 66 — +1 unload test).
- All other consumer suites still green.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
OtOpcUa
OPC UA server (.NET 10 AnyCPU) that exposes a fleet of industrial drivers as a single OPC UA address space. Drivers ship in-process for AVEVA System Platform Galaxy (via the sibling mxaccessgw repo), Modbus TCP, Siemens S7, Allen-Bradley CIP (ControlLogix / CompactLogix), Allen-Bradley Legacy (SLC 500 / MicroLogix), Beckhoff TwinCAT (ADS), FANUC FOCAS, and OPC UA Client (gateway).
A cross-platform client stack (.NET 10) — shared library, CLI, and Avalonia desktop app — connects to any OPC UA server.
Architecture
OPC UA Clients (CLI, Desktop UI, 3rd-party)
|
v
+-------------------------------------+
| OtOpcUa.Server (.NET 10 AnyCPU) |
| address space + capability fan-out|
+-------------------------------------+
| | | | | | | |
Galaxy Modbus S7 AbCip AbLeg TwinCAT FOCAS OpcUaClient
|
v
mxaccessgw (sibling repo, gRPC)
|
v
MXAccess COM (x86 worker, on AVEVA box)
Galaxy is the only driver with an external runtime: it speaks gRPC to a separately installed mxaccessgw server (sibling repo at c:\Users\dohertj2\Desktop\mxaccessgw\) which owns the MXAccess COM apartment and the x86/STA bitness constraint server-side. Everything in this repo is platform-agnostic .NET 10.
Prerequisites
- .NET 10 SDK (server, drivers, clients all target .NET 10)
- SQL Server reachable for the central config DB
- For Galaxy specifically: a running
mxaccessgwdeployment — see docs/v2/Galaxy.ParityRig.md - For Wonderware Historian read-back: optional
OtOpcUaWonderwareHistoriansidecar — see docs/ServiceHosting.md
Quick Start
dotnet restore ZB.MOM.WW.OtOpcUa.slnx
dotnet build ZB.MOM.WW.OtOpcUa.slnx
dotnet test ZB.MOM.WW.OtOpcUa.slnx
# Run the server in dev (foreground)
dotnet run --project src/Server/ZB.MOM.WW.OtOpcUa.Server
The server starts on opc.tcp://localhost:4840 with the None security profile. Configure Security.Profiles in src/Server/ZB.MOM.WW.OtOpcUa.Server/appsettings.json to enable Basic256Sha256-Sign or Basic256Sha256-SignAndEncrypt. See docs/security.md.
Install as Windows Services
Production deployment is driven by scripts/install/Install-Services.ps1, which registers the OtOpcUa server service (and optionally the OtOpcUaWonderwareHistorian sidecar) under a chosen service account. Galaxy support requires a separately installed mxaccessgw — neither this repo nor the install script provisions it.
.\scripts\install\Install-Services.ps1 `
-InstallRoot 'C:\Program Files\OtOpcUa' `
-ServiceAccount 'DOMAIN\svc-otopcua'
Add -InstallWonderwareHistorian for the historian sidecar. See the script header and docs/ServiceHosting.md for full options.
Client CLI
dotnet run --project src/Client/ZB.MOM.WW.OtOpcUa.Client.CLI -- connect -u opc.tcp://localhost:4840
dotnet run --project src/Client/ZB.MOM.WW.OtOpcUa.Client.CLI -- browse -u opc.tcp://localhost:4840 -r -d 3
dotnet run --project src/Client/ZB.MOM.WW.OtOpcUa.Client.CLI -- read -u opc.tcp://localhost:4840 -n "ns=2;s=SomeNode"
dotnet run --project src/Client/ZB.MOM.WW.OtOpcUa.Client.CLI -- write -u opc.tcp://localhost:4840 -n "ns=2;s=SomeNode" -v 42
dotnet run --project src/Client/ZB.MOM.WW.OtOpcUa.Client.CLI -- subscribe -u opc.tcp://localhost:4840 -n "ns=2;s=SomeNode" -i 500
See docs/Client.CLI.md and docs/Client.UI.md.
Documentation
Architecture deep-dives
| Topic | Doc |
|---|---|
| OPC UA server composition, namespace fan-out, Polly invoker | docs/OpcUaServer.md |
| Address space layout | docs/AddressSpace.md |
| Read / Write dispatch (driver vs virtual vs scripted-alarm) | docs/ReadWriteOperations.md |
| Incremental sync (driver-backend rediscovery + config publishes) | docs/IncrementalSync.md |
| Service hosting (Server + Admin + optional historian sidecar) | docs/ServiceHosting.md |
| Security (transport, LDAP, certificates) | docs/security.md |
| Redundancy | docs/Redundancy.md |
| Status dashboard | docs/StatusDashboard.md |
Drivers
| Topic | Doc |
|---|---|
| Driver specs (per-driver capability surface, config, addressing) | docs/v2/driver-specs.md |
| Galaxy driver | docs/drivers/Galaxy.md |
| Modbus / S7 / AbCip / AbLegacy / TwinCAT / FOCAS / OpcUaClient | docs/drivers/ |
| Galaxy parity rig (mxaccessgw setup) | docs/v2/Galaxy.ParityRig.md |
| Galaxy performance + tracing | docs/v2/Galaxy.Performance.md |
Clients
| Topic | Doc |
|---|---|
| Client CLI | docs/Client.CLI.md |
| Client UI (Avalonia desktop) | docs/Client.UI.md |
v1 archive
The original v1 in-process MXAccess docs (Galaxy.Host topology, Configuration env vars, AlarmTracking, DataTypeMapping, HistoricalDataAccess, Subscriptions, etc.) are preserved under docs/v1/ — historical reference only. PR 7.2 retired the v1 architecture on 2026-04-30; current state is documented in the sections above.
License
Internal use only.