romanettandClaude Fable 5
6e791517b5
### Why Follows up on the [review discussion in #4357](https://github.com/OPCFoundation/UA-.NETStandard/pull/4357#discussion_r3903422013): the rule in this codebase is *if you get handed an IDisposable, it is your responsibility to dispose it*, but `CertificateStoreIdentifier.OpenStore` handed every caller the **one** store instance cached on the identifier. A caller honoring the rule disposed shared state other holders of the same identifier were still using (it only appeared to work because the store implementations tolerate use after dispose), while a caller that only called `Close()` left the cached instance — and its parsed-certificate cache — alive with no owner, which is exactly what the certificate leak gates flag at suite end. ### What Of the two options discussed (caller-owned instance vs. a new ref-counted wrapper type), this implements the simpler one, modeled on the existing `CertificateIdentifier` / `Certificate` pair: - `CertificateStoreIdentifier` is now a pure **description** of a store, exactly like `CertificateIdentifier` is for a certificate. It caches nothing and has no disposable-like lifecycle. - `OpenStore` creates and opens a **new instance on every call**, which the caller owns and must dispose — like a resolved `Certificate`. If `Open` throws, the instance is disposed before the exception propagates. - Components that access a store repeatedly keep their instance open for as long as they need it instead of relying on identifier-level caching: the certificate validator already does this via its per-core store cache (`CertificateValidationCore.m_stores`), which now also disposes the loser of its benign `GetOrAdd` race instead of leaking it. - Call sites that relied on the shared cached instance by only calling `Close()` now dispose the store they own: `CertificateTrustList.GetCertificatesAsync`, `SecurityConfiguration` store validation, both `X509Utils` store extensions, the server `TrustList` store-update helpers and the rejected-certificate list read. - New `CertificateStoreIdentifierOpenStoreTests` pin the ownership contract (independent instance per call, disposing one instance does not affect another, empty path returns null). A ref-counted wrapper prototype was implemented and discarded: it forced every short-lived identifier creation site (~20 in src, more in tests) to release a hidden base reference, spreading the disposable-like lifecycle the review objected to across the whole codebase instead of removing it. ### Verified Release, `net10.0`, with `OPCUA_CERTIFICATE_LEAK_TRACKING=1`: - Opc.Ua.Core.Tests: 4376 passed - Opc.Ua.Configuration.Tests: 227 passed - Opc.Ua.Server.Tests: 4797 passed - Opc.Ua.Gds.Tests: 1111 passed - Opc.Ua.Client.Tests (full suite): 2164 passed - Opc.Ua.Core.Security.Tests: 556 passed - Opc.Ua.PubSub.Mqtt.Tests: 157 passed (its strict certificate instance-count test passes unmodified under the new contract) - Opc.Ua.Tools.Tests: 710 passed 🤖 Generated with [Claude Code](https://claude.com/claude-code) --------- Co-authored-by: Claude Fable 5 <noreply@anthropic.com>
OPC UA .NET Standard Stack
🆕 This is version 2.0 of the OPC UA .NET Standard Stack (current
master).Looking for the supported 1.x release? It lives on the
master378branch (last release:1.5.378). All new feature work happens here onmaster;master378continues to receive security and critical-bug fixes for the 1.x line.
The official OPC Foundation reference implementation of OPC UA for .NET — a certified, cross-platform stack with client, server, PubSub, GDS, complex types, and source-generated tooling. Used in production across industrial control, manufacturing, energy, and IoT systems.
📦 What it is
- A full-stack OPC UA implementation — Core / Client / Server / PubSub / GDS / LDS / Complex Types / Device Integration / Positioning libraries built on .NET, with UA-TCP and HTTPS transports.
- Cross-platform — runs on .NET 10, .NET 9, .NET 8 (LTS), .NET Framework 4.8, and .NET Standard 2.1; ships Native-AOT-friendly assemblies.
- Certified for compliance — the reference server has been certified through an OPC Foundation Certification Test Lab and is continuously verified against the latest Compliance Test Tool (CTT).
- Companion-spec coverage — Part 9 (Alarms & Conditions), Part 11 (Historical Access), Part 13 (Aggregates), Part 16 (State Machines), Part 17 (Alias Names), Part 18 (Role Management), Part 20 (File Transfer), Part 100 (Device Integration), Parts 210/211 (Relative Spatial Location and Global Positioning), OPC-10030 (ISA-95 Common Model) with OPC-10031-4 Job Control V1/V2, OPC 30270 / OPC UA for Asset Administration Shell V2 and V3, OPC 10100-1 (WoT Connectivity), OPC 40001-1 (Industrial Automation), OPC 40010-1 (Robotics).
- Modern developer surface — first-class
Microsoft.Extensions.DependencyInjectionhosting (services.AddOpcUa()), fluent server + client builders, source-generated NodeManagers and DataTypes, and an MCP server so LLMs / Copilot can drive an OPC UA client.
For the full feature breakdown see OPC UA Profiles and Facets and the What's New in 2.0 tour.
🚀 Getting started
You need the .NET 10 SDK to build the repo. From the repository root:
dotnet restore UA.slnx
dotnet build UA.slnx
For the supported target frameworks and platform notes see
the Developer Guide. The official NuGet packages
are published to nuget.org under the OPCFoundation.NetStandard
prefix — the meta package
OPCFoundation.NetStandard.Opc.Ua
pulls in everything, or reference individual packages directly, e.g.
OPCFoundation.NetStandard.Opc.Ua.Client for clients or
OPCFoundation.NetStandard.Opc.Ua.Server for servers. Preview builds from
every successful master build are available from the
GitHub Packages NuGet feed.
Official public 2.0 preview releases are also on nuget.org. Enable prerelease
packages and use 2.0.0-preview.* to float to the latest published
2.0.0-preview.N release.
Sample applications
Each sample has its own README.md with build and run instructions.
Reference applications
- Console Reference Server — the certified reference server (with Quickstarts, CTT, and Mono configs). Also ships as a Docker container.
- Console Reference Client — cross-platform reference client demonstrating sessions, subscriptions, browsing, and method calls.
- Console LDS Server — a standalone
Local Discovery Server built on
Opc.Ua.Lds.Server.
PubSub samples
- Console Reference PubSub Client —
one executable with
publisher,subscriber, andexternal(external-server adapter) modes across the supported transport profiles.
Minimal / Device-Integration samples
- Minimal Calc Server — minimal server built on the source-generated NodeManager pipeline (Calc model).
- Minimal Boiler Server — minimal Boiler-model server with the fluent state-machine builder; Native-AOT publishable.
- Pump Device Integration Server —
minimal Device Integration (Part 100) server using
Opc.Ua.Di.Server's fluent builder. - Minimal Robot Server — OPC 40010 Robotics with independently configurable RSL/GPOS motion and live OpenUSD transforms.
- Intent Enabled Robot — one collaborative arm exposing the Robot Intent command surface: task-level motion verbs tracked on a Part 10 program lifecycle, with missions, command authority and safety-aware refusal.
- Intent Viewer Client — click a target in an OpenUSD viewport and watch the arm execute the resulting intent; also runs headless.
- Bin Picking Cell — Robot Intent, Vision, an eye-in-hand camera, and an in-address-space OpenUSD scene in one reference cell.
- Bin Picking Client — closes the Vision-to-Robot-Intent loop, with optional MCP hosting and an OpenUSD viewport.
- Visual Inspection Cell — hosts Vision, AI Model Management, ISA-95 Job Control V2, and an operator dialog for deterministic machined-bracket inspection.
- Visual Inspection Agent — drives
the inspection loop with typed clients, routes inference through deployment
Invoke, applies recipe verdicts, schedules allowlisted jobs, and records operator ground truth. - AI Model Management sample —
ModelManagementServerpublishes the draft AI Model Management catalogue and routes inference;ModelManagementClientdiscovers deployments and exercises the Methods. - Minimal ISA-95 Server — minimal server hosting the OPC-10030 ISA-95 Common Model together with OPC-10031-4 Job Control V1 and V2, using the typed common-model builder and the in-memory Job Control provider.
More sample projects are maintained in the companion OPC UA .NET Samples repository.
Developer tools
- OPC UA MCP Server — installable .NET tool and container that exposes OPC UA client operations as MCP tools for LLMs and Copilot. The tools also ship as libraries (
…Opc.Ua.Mcp.Core,.PubSub,.Diagnostics,.PubSub.Diagnostics) so an application can embed them next to its own MCP tools.
🔧 Migrating from 1.5.378 to 2.0
The 2.0 release introduces breaking API changes, and comes with a full prescriptive migration guide that links to per-area documentation for the migration sub-topics.
Most of the mechanical migration work is automated:
OPCFoundation.NetStandard.Opc.Ua.MigrationAnalyzerNuGet — install it in your project to get 26 analyzer rules throughUA0030(excludingUA0013,UA0016,UA0017, and the shim-onlyUA0029) plus one-click code fixes for the patterns in the guide. Setup steps are in the package's NugetREADME.md.- Migration agent skill — the
opcua-v20-migrationskill walks Copilot / Claude / any coding agent through installing the NuGet, runningdotnet format analyzersto apply auto-fixes, and handling the small residual manual patterns. The skill knows which sub-doc to load for each symptom so it stays context-efficient.
Copilot CLI discovers the skill automatically inside a clone. To install it for use in any repository:
copilot plugin marketplace add OPCFoundation/UA-.NETStandard
copilot plugin install opcua-v20-migration@opcua-dotnet
If you are still on 1.x and not ready to upgrade, stay on the
master378
branch — it continues to receive security and critical-bug fixes.
🤝 Contributing and license
Community contributions are welcome. Fork the repository, make your changes on a branch, and open a pull request; see CONTRIBUTING.md for the contribution workflow.
Contributors must sign the OPC Foundation Contributor License Agreement (CLA). The CLA "I AGREE" gate is presented automatically on your first PR.
The project is licensed under the OPC Foundation MIT License. Report security vulnerabilities via the process documented in SECURITY.md.
📚 Further reading
- Documentation index — every per-feature doc with a one-line description.
- What's New in 2.0 — narrative tour of the 1.5.378 → 2.0 changes grouped by theme and layer.
- OPC UA Profiles and Facets — facets / transports / security policies the stack implements.
- Migration Guide — prescriptive
per-version migration reference (links to
docs/migrate/2.0.x/). - OPC UA Online Reference — the official OPC 10000 series specification index.
- OPC UA .NET Samples — companion repository with more sample applications.
- Preview Nuget package feed —
prerelease builds from every successful
masterbuild.