Joseph Doherty
5ba9f1be6f
Code review of c46540ae approved the framing algorithm but moved the risk onto the contract around it. C1 (critical). SampleAsync returned normally on three different events: EOF, the closing --boundary--, and a response that was not multipart at all (where it yielded one parsed snapshot and finished). The seam documents the stream as yielding until ct is cancelled, so a Task 11 pump written to that contract would silently drop its subscription or hot-loop reconnecting; the non-multipart leg reported a configuration error as a healthy finished stream, which is the #485 quiet-successful-termination shape aimed at the very next task. Every non-cancellation end now throws: MTConnectStreamEndedException (ConnectionClosed / ClosingBoundary - transient) or MTConnectStreamNotSupportedException (configuration - reconnecting reproduces it forever), sharing one catchable base. The non-multipart body is still parsed first so an Agent's own MTConnectError text wins, but the document is NOT yielded. I1. IsSequenceGap moved to IMTConnectAgentClient (static) and its first parameter is now expectedFrom. The old name and doc were wrong for every chunk after the first - the correct comparand is the PREVIOUS chunk's NextSequence, and comparing against the opening "from" argument reports a gap on every chunk once the ring buffer rolls, i.e. an endless /current re-baseline storm. Both doc blocks also now record that cppagent answers from < firstSequence with an OUT_OF_RANGE MTConnectError under HTTP 200, which surfaces as InvalidDataException and NOT as a gap - so Task 11 must treat that parse failure as a re-baseline trigger too. I2. Every multipart test served the whole body from one buffer, so every framing test completed in a single ReadAsync - the split-boundary path, the split-header path and the multi-fill loop were correct by inspection only. A ChunkedStream double (N bytes per read, N = 1/3/7) now drives the fixtures through a split transport, plus a >16 KB document that forces a buffer resize. Falsifiability: removing either scan overlap, or collapsing the fill loop, fails ONLY the new chunked tests. I3. Disposal mid-enumeration surfaces as OperationCanceledException via an internal dispose-linked token, not a raw ObjectDisposedException that Task 9's re-init would inflict on an enumerating pump. I5. HeartbeatMs, SampleIntervalMs and SampleCount join RequestTimeoutMs in construction-time positive-value validation. All three reach the query string and an Agent answers heartbeat=0 with an HTTP-200 MTConnectError that names no config key. I4/M2. The no-Content-length framing fallback logs a one-shot warning (the client takes an optional ILogger); a multipart response with no boundary parameter fails fast instead of degrading into a watchdog timeout. M5/M6. Shared element/attribute reading rules extracted to MTConnectXml; the probe parser documents why it alone does not trim BOM/whitespace. The literal U+FEFF in source became a '' escape. Also, from Task 8: MTConnectObservation gained IsStructured (default false), set from element.HasElements. A DATA_SET/TABLE observation's <Entry> children concatenate through element.Value to nonsense ("12" for two entries) that the index would publish as Good, and only the parser can tell that apart from a legitimate space-bearing Message. False for CONDITION observations - their value comes from the element name, so child content cannot corrupt it. 275/275 green in this suite's own files.
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, OPC UA Client (gateway), and MQTT (broker subscribe; Sparkplug B in progress).
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 MQTT
|
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 historian read-back / alarm history / continuous historization: a running
ZB.MOM.WW.HistorianGatewaydeployment (the sole historian backend; consumed as theZB.MOM.WW.HistorianGateway.ClientgRPC package). It must runRuntimeDb:Enabled=true+RuntimeDb:EventReadsEnabled=true, and the API key must carryhistorian:read+historian:write+historian:tags:writescopes.
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.Host
The server starts on opc.tcp://localhost:4840 with the None security profile. Configure Security.Profiles in src/Server/ZB.MOM.WW.OtOpcUa.Host/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 under a chosen service account. Historian support requires a separately deployed ZB.MOM.WW.HistorianGateway and Galaxy support a separately installed mxaccessgw — neither this repo nor the install script provisions them.
.\scripts\install\Install-Services.ps1 `
-InstallRoot 'C:\Program Files\OtOpcUa' `
-ServiceAccount 'DOMAIN\svc-otopcua'
The historian backend is the external ZB.MOM.WW.HistorianGateway (not installed by this script). 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; external HistorianGateway backend) | 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 / MQTT | 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.