Marc SchierandCopilot
d08d4faec1
# Description Consolidate the complete B01/B02 NodeState memory work into one PR. - Replace eager cold-path NodeState locks with lazy canonical publication and update the event-monitor counter atomically. - Store six design-metadata properties and three security properties in separate lazy private bags while preserving public APIs, null/empty distinctions, masks, copying and existing serialization behavior. - Avoid allocating the ReportEvent scheduling closure when the async-dispatch path is unused. - Retain the logger factory's category logger directly, avoiding a redundant typed wrapper on telemetry initialization. - Keep Variant at 24 bytes while removing eligible outer boxes for QualifiedName, NodeId, NET8+ ByteString and text-only LocalizedText values. - Add reproducible allocation/layout/occupancy fixtures, real registered and monitored populations, reference contracts, generated-consumer coverage and NativeAOT cases. ## Measured allocation changes Matched .NET 10.0.11 x64 observations against the integrated master baseline: | Construction/assignment | Master | This PR | |---|---:|---:| | Bare/minimal object | 824 B | 640 B | | Bare/minimal variable | 1160 B | 976 B | | Variable with both optional groups populated or reset | 1160 B | 1088 B | | Variable with a shared ByteString value | 1192 B | 976 B | Separate paired measurements show: - telemetry initialization: 24 B typed-logger wrapper removed; - eligible QualifiedName, NodeId and ByteString Variant construction: 32 B to 0 B; - eligible text-only LocalizedText Variant construction: 40 B to 0 B; - variable attributes read into caller-provided Variant destinations: 136 B to 0 B. These are runtime-specific per-operation observations, not additive whole-server savings. Optional bags retain their documented populated/high-water premiums and are not reclaimed on reset. ## Reference-storage decision A complete private indexed reference backend and a sorted-traversal alternative were measured, but both changed the existing filtered hash-index enumeration order. They were rejected despite lower memory use. The production reference backend remains unchanged; strengthened ordering, identity, serialization and concurrency contracts are retained. Adaptive small-set storage remains deferred. ## Consolidation This PR now contains all changes from #4451 and the former narrower #4452 branch. Every #4452 changed path was present in #4451; after merging, the #4451 head `836e45226` is a direct ancestor of this branch. #4451 is closed as superseded. Draft #4425 remains unchanged and is also superseded by this consolidated work. ## Review feedback - Removed the standalone Variant storage document and its README entry. - Made the raw NodeId constructor private; the documented internal `GetRawState`/`SetRawState` bridge is explicitly Variant-only and must never become public. - Marked the two 32-thread counter tests non-parallel. - Added 10-second timeouts to the concurrent browse benchmark's main and worker barriers and completion waits. - Migrated the registered-population fixture to the current async `SealAsync` API. All review threads on #4451 and #4452 were replied to with the action and fix commit, then resolved. ## Related issues - Related to #4275. - Supersedes #4425 and #4451. ## Validation - Consolidated Types/Core/Server selection: **1241 passed** on net10.0. - Consolidated Types/Core/Server selection: **1238 passed** on net48. - Focused #4451 feedback selection: **189 passed** on net10.0 and **187 passed** on net48. - Earlier integrated NativeAOT validation passed **163/163** cases across the main, MCP and Historian applications; current PR CI provides the authoritative final merged-source native validation. The first #4452 CI run was blocked by merge conflicts. Seven later jobs completed their tests but encountered a shared artifact-service HTTP 403 while uploading results; no workflow or test was weakened to mask that infrastructure failure. Generated `report.*.json` crash artifacts remain untracked and are not part of this PR. ## Checklist - [ ] 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 the changes and improve coverage. - [x] I have added the necessary current-behavior documentation. - [ ] I have verified that the fresh consolidated CI run introduces no build or analyzer warnings. - [ ] I ran the complete UA.slnx suite locally on net48 and net10.0 with no failures. - [ ] I fixed all failing and flaky CI tests and all CodeQL warnings. - [x] I have addressed all PR feedback received. --------- Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> Copilot-Session: d2569e2e-7115-4969-bb44-8159e302b450
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.
Samples
The stack also includes a large collection of platform-independent sample applications that turn its core services and companion models into runnable client/server workflows. More applications, including platform-specific examples, are available 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.
- Preview Nuget package feed —
prerelease builds from every successful
masterbuild.