# Description
Adopt
[`System.TimeProvider`](https://learn.microsoft.com/dotnet/api/system.timeprovider)
across the stack so that every place that creates timers, runs duration
math, or schedules periodic work is mockable, deterministic in tests,
and immune to wall-clock changes.
The migration touches Core, Core.Types, Server, Client, PubSub,
Configuration, Gds (server + client), Lds, and the Quickstarts/Console
reference apps. Per-component changes follow the same pattern:
1. Add a `private readonly TimeProvider m_timeProvider;` field.
2. Accept a nullable `TimeProvider? timeProvider = null` as the **last**
constructor parameter (new overload; legacy constructor stays for binary
compatibility and delegates with `timeProvider: null`).
3. Initialise the field with `m_timeProvider = timeProvider ??=
TimeProvider.System;`.
4. Replace `new Timer(...)`, `Stopwatch`, `HiResClock.*`,
`DateTime.UtcNow`-based duration math, and `Task.Delay(delay, ct)` in
timing loops with the matching `m_timeProvider` API (`CreateTimer`,
`GetTimestamp` / `GetElapsedTime`, `GetUtcNow().UtcDateTime`,
`Task.Delay(delay, m_timeProvider, ct)`).
5. Wire the provider through DI: `AddOpcUaServerBuilder` /
`AddOpcUaClientBuilder` register `TimeProvider.System` via
`TryAddSingleton<TimeProvider>()` so tests can swap in
`Microsoft.Extensions.Time.Testing.FakeTimeProvider`.
`HiResClock` itself is kept (so the
`ApplicationConfiguration.DisableHiResClock` schema flag still
round-trips), but **every public member** is now `[Obsolete]` with a
single shared message pointing to the new migration-guide section. The
few internal call sites that still need to set/read `HiResClock` are
wrapped with `#pragma warning disable CS0618`.
### Highlights per component
- **Core / Stack** — `Opc.Ua.Core`, `Opc.Ua.Core.Types`, channel
pipeline (`UaSCBinaryClientChannel`, `ChannelToken`,
`UaSCBinaryChannel`), `ApplicationConfiguration`, certificate
validators, `JwksIssuerKeyResolver`, `TimeProviderExtensions` polyfills
(`GetTimestampMilliseconds`, `GetTickCount`,
`CancellationTokenSource(timeout, timeProvider)`, `Task.Delay(delay,
provider, ct)` polyfill for older TFMs).
- **Server** — session lockout, subscription pipeline
(publish/sample/keep-alive/lifetime), `MonitoredItemQueue`, alarm
sampling rate, `IntervalRunner`, server diagnostics, configuration state
machines, hosted services.
- **Client** — `Session`, managed/V2 subscription engines, reconnect
handlers, channel keep-alive, periodic publishing, complex-type
discovery polling.
- **PubSub** — `IntervalRunner` pipeline, message-receive timers,
MQTT/UDP keep-alive, publishers/readers.
- **Gds / Lds** — `LdsServer`, `LinqApplicationsDatabase` expiry
housekeeping, GDS clients (push, pull), `DirectoryCertificateStore`,
`ConnectionStateMachine`, classic subscription engine.
- **Quickstarts / Console samples** — `SampleNodeManager`,
`ReferenceNodeManager`, `AlarmNodeManager`, `BoilerState`,
`MemoryBufferState`, `PublishedValuesWrites`. Samples resolve via
`(Server as ITimeProviderProvider)?.TimeProvider ?? TimeProvider.System`
so existing ctor signatures stay binary-compatible.
- **Tests** — `Opc.Ua.PubSub.Tests` adds `IntervalRunnerTests`; existing
`SubscriptionTests`, `UaPublisherTests`, and `TestDataSystem` move off
`HiResClock`. Added `Microsoft.Extensions.TimeProvider.Testing` package
for `FakeTimeProvider` (project-load warning surfaces on net48/net472
only — runtime is .NET 8+).
### Migration guide
New section [**Time and Timer abstraction
(`TimeProvider`)**](Docs/MigrationGuide.md#time-and-timer-abstraction-timeprovider)
documents:
- The canonical replacement table (`HiResClock.UtcNow` →
`timeProvider.GetUtcNow().UtcDateTime`, `HiResClock.TickCount64` →
`timeProvider.GetTimestamp()`, `new Timer` → `timeProvider.CreateTimer`,
`Task.Delay(delay, ct)` → `Task.Delay(delay, timeProvider, ct)`, …).
- The `TimeProvider? timeProvider = null` + `??=` constructor pattern.
- DI wiring and how to swap in `FakeTimeProvider` in tests.
- Before/after snippets for `HiResClock.TickCount64`,
`HiResClock.UtcNow`, and `new Timer(...)`.
## Related Issues
- Fixes#2458
## 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.
- [ ] 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.
* New certificate and secrete abstraction with certificate infrastructure and certificate/secret stores.
* leak testing for certificate resources to validate new ref counting in every test assembly
* Migration guide updated and documentation added for all
* Remove IDisposable from Nodestate and UserIdentity.
* UserCertificateTokenHandler now just points into certificate registry/stores, no dispose required
* Fix CA2000 warnings and cleanup of other diagnostics, increase warning levels in .editorconfig
- Add new managed session, wrapping session and providing connection management and failover handling
- Add new Subscription engine that can act as alternative to current engine, but is based on channels with worker tasks
- Add a fluent builder for managed session clients
- Replace NodeCache with LruNodeCache, rename ILruNodeCache and LruNodeCache to INodeCache and NodeCache
- Update migration guide and document new functionality.
* make most ptojects aot compatible
* Remove newtonsoft
* Migrate all projects from Mono.Options to System.CommandLine 2.0.5
* Fix array clone
* Replace serializers for storage using new attribute driven type geberator
* Add new AOT integration tests covering all functional areas
* Documentation updates
Refactored client-side logic to support batching of service requests, ensuring compliance with operation limits and improving scalability. Added telemetry and activity tracing using `ActivityTraceFlags` for better observability, including metrics collection and logging. Enhanced error handling with descriptive exception messages and improved certificate validation.
Introduced a comprehensive suite of unit tests for `SessionClientBatchTests.cs` and `ClientBaseTests.cs`, covering batching, error scenarios, and edge cases. Added helper classes for testing logging, metrics, and activity tracing. Updated tests to align with modern C# practices, including nullable reference types and collection initializers.
Improved code consistency, readability, and maintainability by standardizing method signatures, simplifying redundant patterns, and removing legacy constructs. Updated XML documentation and added conditional compilation for .NET 8.0+ compatibility.
* Added RejectCertificateUriMismatch property and explicit ApplicationUri validation after certificates are loaded
* Perform duplicate detection on thumbprint only
* Ported handle multiple ApplictionUri, removed assign ApplictionUri from certificate
* Missing letter
* Fixed LoadPrivateKeyAsync when no applicationUri is passed.
* Add tests for validating certificates with multiple AplicationUris on ApplicationInstance level and server side
* Renamed into CheckOrCreateCertificateAsync, logged Certificate, improved tests
* Added retry logic for transient connect errors in CreateSessionApplicationUriValidationTests
* Added TODO log when telemetry instance available
* Removed unused ValidateServerCertificateApplicationUri(X509Certificate2 serverCertificate)
- Replaced `IList<INode>` with `List<INode>` in
`ComplexTypeSystem.cs` and `BaseComplexType.cs` for
better type safety.
- Updated string comparison in `ReverseConnectManager.cs`
to `StringComparison.Ordinal` for improved performance.
- Added a method to `ISession.cs`, `Session.cs`, and
`SessionAsync.cs` to trigger reloading instance certificates.
- Minor fixes in error handling in `Subscription.cs` and using pattern matching for type checks in several locations to improve code readability.
- Made minor adjustments to comments and documentation
for clarity and improved code quality.
- Updated `Variant` handling in preparation for immutable struct.
- Changed return types in `BaseObjectState.cs` and `BaseVariableTypeState.cs` to use `ObjectTypeIds` for iperf
- Cleaned up `ExpandedNodeId`
- Enhanced memory management error handling and readabilityand error handling in encoders
- support for Microsoft.Extensions.Logger.ILogger in Opc.Ua.Core as the new logging interface
- backward compatible with config and TraceEvents
- new API Utils.SetLogger allows to set ILogger
- updated Console samples to demonstrate ILogger support with Serilog
- support for EventSource logging
- see Docs/Logging.md for more info
- Add Operation limit parameter and fix server. Fixes#1363
- Add client/server test projects
- Add client and server fixture for test runs
- Server tests can test services without client connection
- Client tests can use common services to write tests which can run directly on server on via client server connection
- Increase code coverage > 50%
- Code coverage excludes the generated code
- Improve codecoverage local tests with report (see Tests/codecoverage scripts)
- Add a benchmark framework to client server tests
- remove use of Bouncy Castle for .NET Core 3
- refactor CreateCertificate class to allow for an easier Create fluent model with respect to future extensions, e.g. ECC
- reimplement X509CRL and a couple of extension relevant for OPC UA based on the new System.Formats.Asn1 library
- use CertificateRequest on .NET Core 3.1
- refactor codebase to allow for a seperate library to handle all the ASN.1 encoding/decoding
- new package Opc.Ua.Security.Certificates with all ASN.1 encode/decode related code
breaking change: many X509 related util functions were moved to X509Utils class
Note: .NET 4.6.2 and .NET Core 2.1 versions still use BouncyCastle for Cert creation
- no bug fixes, just documentation and formatting
- fix all warnings for xml in core libraries, except
-- protected members
-- suppressed warnings in Opc.Ua.Gds libraries (tbd)
- This improvement was tested with an aggregation server update on this branch:
Required for testing: https://github.com/mregen/UA-.NETStandard-Samples/tree/aggregationserver
Main changes:
- Support holding of reverse connections, then a client can connect faster on a hold connection instead of waiting for the next reverse hello.
- Simplify API to connect with or without reverseconnect manager.
- Reconnect handlers code path added, tested with SessionReconnectHandler
- some locks on lists were not correctly implemented.
Marc Schier