Files
UA-.NETStandard/samples/GeneratorServer/Program.cs
Marc Schier ca89ac85a7 Add a Generators companion-spec sample and compose servers at a site level (#4180)
# Description

Adds a **Generators companion-specification sample** alongside the
existing pump sample, and a **`SiteCompositionServer`** that composes
several device servers into one OpenUSD scene at a supervisory level —
demonstrating that servers can be aggregated without mirroring their
address spaces.

Three things, in dependency order:

### 1. `GeneratorServer`

A self-contained server realising the draft Generators spec
(`http://opcfoundation.org/UA/Generators/`) end to end: N simulated
generating sets, DI + Machinery integration, a twelve-state operating
state machine, four protection alarms per set, six control methods, and
a per-set OpenUSD twin.

The organising idea is that **load fraction is the only independent
variable**. Everything else is a function of it:

```
V̇_f(x) = 3.67 + 100·x                fuel rate      [L/h]
η(x)   = P(x) / (V̇_f(x) · ρ · LHV)   efficiency
S = P / PF     I = S / (√3·V_LL)     f = N·p / 120
```

This is not stylistic. When each measurement is an independent
oscillator — as the pump sample's simulation once was — a server happily
publishes a duty point no real machine could occupy, and no test can
catch it because there is nothing for the values to be inconsistent
*with*. Deriving them from one variable means `P = √3·V·I·PF` and `η =
P/(V̇·ρ·LHV)` hold at every tick by construction. The published
`DATASHEET.md`, the engineering ranges, the trip points and the
simulation all read the same constants in `GeneratorDatasheet.cs`, so
the document and the server cannot describe different machines.

The machine is a fictitious **SimGen Systems GenX-500** (400 kW prime /
440 kW standby, 400/230 V, 50 Hz, four-pole). Figures are representative
of a real industrial genset class; no vendor is named anywhere in the
code or docs.

### 2. Cross-server composition in the connector

`RemoteSessionFactory` already existed in the client library but the
connector CLI never set it, so cross-server composition was unreachable.
`--federate` wires it up: the connector opens a session to each server
named by a component binding, discovers its representations and drives
its bindings into the same stage.

It is **opt-in** because the endpoint the connector dials comes from the
server being rendered rather than from the operator, which makes
honouring it a trust decision. Federation is best-effort per component —
a subordinate that is down is logged and skipped, and the rest of the
scene still renders — which is the only `src/` change in this PR.

### 3. `SiteCompositionServer`

Owns no devices. It publishes a site stage plus one cross-server
component binding per subordinate, carrying that server's
`ComponentServerUri` and `ComponentEndpointUrl`. Nothing is mirrored, so
there is no cache to invalidate and no second copy of the truth.

## Notes for reviewers

**Everything interesting in this PR was found by running the servers,
not by reading the code.** Six defects, none of which looked wrong in
review:

- `IsShutdown` and `SubsystemName` are *optional* on
`GeneratorProtectionAlarmType`, so the generated factory does not
materialise them. `CreateOrReplace` alone produces a child that exists,
appears in `GetChildren` and holds the right value — but carries **no
`ReferenceTypeId`**, so no browse can reach it. Every alarm was
publishing its trip without saying whether the trip stops the machine or
which subsystem to go to. `AddXxx(context)` first is what gives the
child its `HasProperty` reference.
- **The protections could never fire.** Every trip point sits outside
the band the datasheet curves produce — that is what a datasheet *means*
— so all four alarms, the shutdown class, `ResetFaults` and the whole
`Fault` branch of the state machine were unreachable while the README
documented them as observable. Overload was worse: the load clamp
ceiling was set to exactly the trip point, making a
strictly-greater-than comparison unsatisfiable. Faults are now
injectable, and the first set — the one the hero camera frames —
develops one on a slow rotation.
- **A shutdown trip removes the condition that caused it**, because oil
pressure and coolant temperature are only supervised while the engine
turns. Each alarm went active for one tick and cleared, leaving an
operator with a stopped machine and no indication of why. Shutdown-class
alarms now latch until the set leaves the shutdown state. Every unit
test that checked the *condition* passed throughout — the defect only
appears when the trip and the supervision interact over time.
- **`Synchronizing` and `Paralleled` were declared, drawn in the README
and never entered.** The first set now energises a dead bus and closes
onto it while every other set synchronises to a live one — both how a
real plant parallels, and what makes the two states observable.
- **The tick raced client method calls.** The simulation tick runs on a
thread-pool thread while method calls arrive on request threads, and
both transition sets and write the same nodes. A tick moving a set to
`Cooldown` and a concurrent `EmergencyStop` could interleave the paired
`CurrentState` / `CurrentState.Id` writes and leave a client with a
state *name* from one transition and a state *node* from the other — the
exact failure the paired write exists to prevent, reintroduced by the
threading model. Both paths now take one gate.
- Low oil pressure supervised from raw speed **tripped every set during
cranking**, because pressure has not built yet. Now gated on
`IsSpinning`, which is what a real start-up bypass does.

Smaller fixes: shutdown trips are applied after the whole evaluation
pass (stopping mid-loop made the remaining conditions read healthy,
collapsing simultaneous trips to whichever came first in the table);
`ResetFaults` reports its clears as events (a client learns of condition
state changes only through events, so a silent clear leaves an
alarm-list client showing it forever); the start counter moved into the
transition so commanded starts are counted; the federated connector
closes the remote session if the connector constructor throws between
taking ownership and registering it; and `prepare_machinery_nodeset.py`
now *asserts* the IA namespace is last before removing it rather than
only claiming so in its docstring — removing any earlier entry would
silently renumber every namespace after it and rebind their NodeIds.

**A model limitation is left visible rather than papered over.**
`GeneratorStateMachineType` declares an emergency stop only out of
`Running`, `Loaded` and `Paralleled`, so the sample refuses
`EmergencyStop` from `Starting` and `Warmup`. A real panel stops from
anywhere. That is the specification's shape, not this sample's choice,
so it is pinned by a test and named in the docs.

**`Model/` vendors a reduced Machinery nodeset**, derived mechanically
by whitelist. The full official nodeset does not survive the model
source generator (`MODELGEN003`) and drags in IA through a single
optional `Stacklight` member a generating set does not have. Deriving it
by script keeps the provenance checkable; the whitelist is the only
thing to edit when more types are needed. **Never hand-edit the
generated output.**

**The federated scene renders end to end.** Getting there surfaced three
more defects, all of which produced a plausible-looking scene with
nothing in it: the generator sample's plant aggregation was created
under an already-registered `DeviceSet` and so was invisible to every
client (it had *never* rendered geometry, standalone or federated); the
connector's asset fetch ran on the primary session only, so composition
referenced layers that were never downloaded; and both generator colour
bindings wrote `primvars:displayColor` to prims that did not declare it,
so the renderer rejected every update while the file still looked
correct. Cross-server components compose under the subordinate's own
root, so the site layer now *places* `/Plant` and `/Powerhouse` rather
than leaving them stacked on the origin.

**`OpenUsdRepresentation` is now mounted with `HasAddIn`, not
`HasComponent`** (review feedback). The nodeset says so explicitly —
*"Mounted with HasAddIn"* — but every server in the tree used plain
`HasComponent`. It survived because `HasAddIn` is a *subtype* of
`HasComponent`: the representation still browses, still aggregates and
still drives a twin, so every functional test passed before the fix and
after it, and only a conformance checker could tell. Seven mount sites
corrected. `PumpDeviceIntegrationServer` and `MinimalRobotServer` had
hand-rolled the mount instead of calling the shared
`CreateRepresentation` helper, which is exactly how they drifted from
it. Both sample E2E suites now assert the reference type across
**every** discovered representation — a narrower check would have missed
the plant-level representation that arrived later from master still
carrying `HasComponent`.

**Live colour is not achievable in the current OpenUSD viewer, and that
is now documented rather than worked around.** Proven with a standalone
probe: `primvars:displayColor` resolves as `color3f[]` from the
`UsdGeomGprim` schema whatever the layer declares, and the `OpenUsd
0.4.0-alpha` managed API has no writer for that type. Bound
`UsdPreviewSurface` materials are not shaded either, so geometry renders
grey unless it also carries an explicit `displayColor` primvar. The
**visibility** bindings carry no such caveat and are what the samples
rely on to show state. Filed upstream as
[openusd-dotnet#2](https://github.com/marcschier/openusd-dotnet/issues/2),
[#3](https://github.com/marcschier/openusd-dotnet/issues/3) and
[#4](https://github.com/marcschier/openusd-dotnet/issues/4), and linked
from `docs/OpenUsd.md` so a reader can check whether they have since
been fixed.

## Related Issues

No tracking issue — this is additive sample and documentation work with
a single small, self-contained change to `src/` (per-component error
isolation and session-ownership hardening in
`OpenUsdConnector.Composition.cs`). Happy to open one if maintainers
would prefer it tracked.

## Checklist

- [x] I have signed the
[CLA](https://opcfoundation.org/license/cla/ContributorLicenseAgreementv1.0.pdf)
and read the
[CONTRIBUTING](https://github.com/OPCFoundation/UA-.NETStandard/blob/master/CONTRIBUTING.md)
doc.
- [x] I have added tests that prove my fix is effective or that my
feature works and increased code coverage.
- [x] I have added all necessary documentation.
- [x] I have verified that my changes do not introduce (new) build or
analyzer warnings.
- [x] I ran **all** tests locally using the **UA.slnx** solution against
at least .net **framework** and .net **10**, and all passed.
- [ ] I fixed **all** failing and flaky tests in the CI pipelines and
**all** CodeQL warnings.
- [ ] I have addressed **all** PR feedback received.

### Testing

The generator fixtures live in `tests/Opc.Ua.OpenUsd.Tests/Generator` —
**82 tests**, no new project. `Opc.Ua.Di.Tests` would have been the
natural home next to the pump fixtures, but both device samples
source-generate their own reduced `Opc.Ua.Machinery` model and expose it
via `InternalsVisibleTo`, so referencing both from one assembly makes
every Machinery type ambiguous (CS0433); `Opc.Ua.OpenUsd.Tests`
references no other sample and already hosts `RobotAssetContractTests`.
The suite runs **870** on net10.0 and net48 (784 existing + 86) and
**788** on net472, where the sample does not exist and only the
framework-independent asset-contract tests run — forgetting exactly that
exclusion broke CI on the sibling pump PR.

The tests target the things in this sample that fail *quietly*:

- **Datasheet conformance** holds the model to its own claim — rated
speed is `120·f/p`, rated current follows from the rating, the fuel
curve reproduces the published table, and `η = P/(V̇·ρ·LHV)` reconciles
at every load. Efficiency is swept across the whole simulated range to
show it stays inside (0,100) and rises monotonically; a fit that goes
negative somewhere in its range is a coincidence that happens to look
right at the duty point, not a model. A further test reads
`DATASHEET.md` and checks the document quotes the figures the server
actually serves.
- **Drift between the two descriptions of the state machine** — the
physics' `IsLegalTransition` and the model's `GeneratorStateMap` — is
checked in *both* directions. A transition the physics permits but the
map lacks moves a machine without telling a client; one the map holds
but the physics refuses is dead weight that looks supported.
- **Reachability at run time**, not just in the declared table — the
test that catches states the model declares and nothing ever enters.
- **That every protection can actually fire**, which is the half of the
alarm contract that "a healthy set annunciates nothing" does not cover.

A **hosted end-to-end fixture** connects a real client and asserts what
the address space actually exposes — the aggregation at
`/Powerhouse/Generators`, its component binding, and every per-set twin.
That is the only kind of test that catches the registration defect
above: the node object had the right browse name, binding and asset
reference, so every test that inspected objects passed while no client
could see it.

**Every state-machine and protection fix was checked by mutation.**
Restoring the clamp ceiling, the direct `Running → Loaded` path, the old
start-counter placement, or removing the alarm opt-in each makes the
corresponding test fail, naming the specific defect. A test that has
never been seen to fail has not been shown to work.

Verified against a running plant: `Synchronizing`, `Paralleled` and
`Fault` all observed on a two-set server, with
`HighCoolantTemperatureAlarm` seen active on the fault subject. Method
behaviour verified separately — per-set distinct `CurrentState` nodes,
`EmergencyStop` → `EmergencyStopped` with `Start` then refused as
`BadInvalidState`, `ResetFaults` → `Off`, `SetOperatingMode(9999)`
refused with the mode unchanged, and the other sets untouched
throughout. Also verified as a three-server federated stage.

0 warnings on a clean Release rebuild of both samples, the client
library, the connector and the tests, across every TFM.

---------

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Copilot-Session: fe608993-f3c9-4779-a6b9-9a9eabfc24ba
2026-08-07 10:48:02 +02:00

136 lines
5.2 KiB
C#

/* ========================================================================
* Copyright (c) 2005-2025 The OPC Foundation, Inc. All rights reserved.
*
* OPC Foundation MIT License 1.00
*
* Permission is hereby granted, free of charge, to any person
* obtaining a copy of this software and associated documentation
* files (the "Software"), to deal in the Software without
* restriction, including without limitation the rights to use,
* copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following
* conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
* OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
*
* The complete license agreement can be found here:
* http://opcfoundation.org/License/MIT/1.00/
* ======================================================================*/
using System;
using System.Globalization;
using System.IO;
using System.Threading.Tasks;
using Generators;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Logging;
using Opc.Ua;
using Opc.Ua.Di.Server.Builders;
using Opc.Ua.Generators;
using Opc.Ua.Server.Fluent;
HostApplicationBuilder builder = Host.CreateApplicationBuilder(args);
builder.Logging.ClearProviders();
builder.Logging.AddConsole();
int port = int.TryParse(builder.Configuration["port"], out int p) ? p : 62543;
if (!TryReadGeneratorCount(builder.Configuration["generators"], out int generatorCount, out string? error))
{
Console.Error.WriteLine(error);
return 2;
}
// Bind host for the OPC UA endpoint. Defaults to 0.0.0.0 so the server is
// reachable from outside a container; override with --host (for example
// "localhost" for local-only development).
string host = builder.Configuration["host"] is { Length: > 0 } h ? h : "0.0.0.0";
// A set running to its datasheet cannot protect-trip, so by default the last set
// develops faults on a slow rotation to exercise the alarm path. Pass
// --faults false for a purely healthy plant.
bool injectFaults = !bool.TryParse(builder.Configuration["faults"], out bool f) || f;
builder.Services.Configure<GeneratorDeviceIntegrationOptions>(options =>
{
options.GeneratorCount = generatorCount;
options.InjectFaults = injectFaults;
});
builder.Services
.AddOpcUa()
.AddServer(o =>
{
o.ApplicationName = "GeneratorServer";
o.ApplicationUri = "urn:localhost:OPCFoundation:GeneratorServer";
o.ProductUri = "uri:opcfoundation.org:GeneratorServer";
// Sample convenience only; never auto-accept untrusted certificates in production.
o.AutoAcceptUntrustedCertificates = true;
o.PkiRoot = Path.Combine(AppContext.BaseDirectory, "pki");
o.RejectSHA1Certificates = true;
o.MinCertificateKeySize = 2048;
o.EndpointUrls.Add($"opc.tcp://{host}:{port}/GeneratorServer");
})
.AddNodeManager<GeneratorNodeManagerFactory>()
// Demonstrate the declarative DI topology-element builder once the node
// manager has materialised and wired every set. Registering this also puts
// the post-setup runner in the container, which is what lets the node
// manager factory receive the configured options.
.ConfigureDevicesFor<GeneratorNodeManager>(ctx =>
{
var manager = (GeneratorNodeManager)ctx.Manager;
foreach (NodeId setNodeId in manager.GeneratorNodeIds)
{
ITopologyElementBuilder<GeneratorSetState> set =
ctx.TopologyElement<GeneratorSetState>(setNodeId);
set.WithFunctionalGroup(
new QualifiedName("Diagnostics", ctx.Manager.InstanceNamespaceIndex),
fg => fg.Configure(node =>
node.WithProperty("LastProtectionTrip", Variant.From(string.Empty), p => p.Writable())
.WithProperty("TripCount", 0)
.WithProperty("LastServiceDate", (DateTimeUtc)DateTime.UtcNow)));
}
return new ValueTask();
});
await builder.Build().RunAsync().ConfigureAwait(false);
return 0;
static bool TryReadGeneratorCount(string? value, out int generatorCount, out string? error)
{
const int minCount = 1;
const int maxCount = 100;
generatorCount = 2;
error = null;
if (string.IsNullOrWhiteSpace(value))
{
return true;
}
if (!int.TryParse(value, NumberStyles.Integer, CultureInfo.InvariantCulture, out int parsed) ||
parsed < minCount || parsed > maxCount)
{
error = FormattableString.Invariant($"Invalid --generators value '{value}'. Specify an integer between {minCount} and {maxCount}.");
return false;
}
generatorCount = parsed;
return true;
}