6 Commits

Author SHA1 Message Date
Marc Schier 0fbc900919 Add opt-in SubscriptionRecoveryPolicy for unsolicited Good_SubscriptionTransferred (#3540) (#3847)
# Description

Adds an opt-in `SubscriptionRecoveryPolicy` for both the Classic V1 and
V2 subscription engines that lets the client recover from server-emitted
`Good_SubscriptionTransferred` notifications which arrive against a
freshly created subscription (observed against Kepware after a server
re-initialise, very likely a leak from the pre-restart session's pending
status notifications onto the new session — abetted by Kepware re-using
`SubscriptionId = 1` across generations).

Per [OPC UA Part 4
§5.14.7](https://reference.opcfoundation.org/Core/Part4/v105/docs/5.14.7),
`Good_SubscriptionTransferred` is supposed to be delivered to the *old*
Session whose subscription was transferred away via
`TransferSubscriptions`. The existing V1 behaviour of stopping the
per-subscription publish loop on receipt is therefore
**spec-compliant**; the issue is that some servers deliver the
notification on a Session that is still actively using the subscription,
leaving the per-subscription dispatch silently disabled.

The fix is **opt-in** and **non-breaking**:

- New `SubscriptionRecoveryPolicy` enum (`ReportOnly` default,
`RecreateOnUnsolicitedTransfer`).
- V1 Classic `Subscription.RecoveryPolicy` property; V2
`Subscriptions.SubscriptionOptions.RecoveryPolicy` init property.
- When the policy is `RecreateOnUnsolicitedTransfer`, the SDK drops
queued acks for the dead subscription id (avoiding
`BadSubscriptionIdInvalid` ack errors on servers that re-use ids) and
recreates the subscription in place on the same Session.

## What changed

**Public API additions (non-breaking, defaults preserve current
behaviour):**
- `SubscriptionRecoveryPolicy` enum (`ReportOnly`,
`RecreateOnUnsolicitedTransfer`).
- V1 `Subscription.RecoveryPolicy` property.
- V2 `Subscriptions.SubscriptionOptions.RecoveryPolicy` init property.
- Internal `IMessageAckQueue.DropPendingForSubscription(uint)` and
protected `MessageProcessor.AckQueue` accessor.

**V1 Classic —
`Libraries/Opc.Ua.Client/Subscription/Classic/Subscription.cs`:**
- Replaces the inline `Good_SubscriptionTransferred` branch with
`HandleGoodSubscriptionTransferred`. `ReportOnly` preserves the original
behaviour (stop publish timer/worker); `RecreateOnUnsolicitedTransfer`
triggers `TriggerUnsolicitedTransferRecovery`, guarded by
`m_recreateAfterTransferInProgress` for idempotency.
- Recovery drains pending acks via the new
`ClassicSubscriptionEngine.RemoveAcknowledgementsForSubscription`
**before** resetting the subscription, then runs `DeleteSubscription()`
+ `CreateAsync()` on the same session so the publish worker restarts via
`StartKeepAliveTimer`.
- Discriminator (`Session != null && !Session.Reconnecting && Created`)
defers to the reconnect pipeline if it is already running.

**V2 — `Libraries/Opc.Ua.Client/Subscription/Subscription.cs`:**
- Completes the `OnStatusChangeNotificationAsync` TODO: now always fires
`OnPublishStateChanged(mask)` so `PublishState.Transferred` actually
reaches handlers (previously the no-op override silently swallowed the
flag).
- Under `RecreateOnUnsolicitedTransfer`, calls
`AckQueue.DropPendingForSubscription(deadId)` then existing
`ResetToRecreateAsync` on a worker task — no service calls from the
dispatch path.
- V2 `SubscriptionManager` implements `DropPendingForSubscription` via
drain-and-refill on the prioritised ack channel.

**Tests — `Tests/Opc.Ua.Client.Tests/Subscription`:**
- V1 in `Classic/SubscriptionUnitTests.cs`:
`ReportOnlyPolicyDoesNotRecreateOnUnsolicitedTransferAsync`,
`RecreatePolicyRecreatesSubscriptionOnUnsolicitedTransferAsync`,
`RecreatePolicyCollapsesConcurrentNotificationsAsync`,
`RecreatePolicyDoesNotRecreateWhileSessionReconnectingAsync`.
- V2 in `SubscriptionTests.cs`:
`GoodSubscriptionTransferredRaisesPublishStateTransferredAsync`,
`GoodSubscriptionTransferredRecreatesSubscriptionWhenPolicyEnabledAsync`,
`GoodSubscriptionTransferredCollapsesConcurrentRecreatesAsync`.
- `FakeMessageAckQueue` gained a `DroppedSubscriptions` recorder so the
V2 test can assert ack pruning ran.

**Docs — `Docs/TransferSubscription.md`:**
- New "Recovering from unsolicited `Good_SubscriptionTransferred`"
section with spec context, usage examples for both engines, and the
caveat that recovery is recreate-based — **not** lossless failover; the
server-side retransmission queue and triggering relationships tied to
the invalidated subscription id are not preserved.

## Validation

| Scope | Result |
| --- | --- |
| `Libraries/Opc.Ua.Client` build (`net10.0`, `net48`) | 0 warnings, 0
errors |
| `Tests/Opc.Ua.Client.Tests` build (`net10.0`, `net472`) | 0 warnings,
0 errors |
| New tests on `net10.0` and `net472` | 7/7 pass on each |
| Full subscription unit-test suite (`SubscriptionUnitTests` +
`SubscriptionTests` + `MessageProcessorTests` +
`SubscriptionManagerTests`) | 110/110 pass on each TFM |
| Entire `Opc.Ua.Client.Tests` suite (`net10.0`) | 1268/1268 pass |
| Classic transfer integration tests
(`Tests/Opc.Ua.Subscriptions.Classic.Tests`, `net10.0`) | 20/20 pass |
| V2 transfer compliance tests (`Tests/Opc.Ua.Subscriptions.Tests`,
`net10.0`) | 9/9 pass |

> Marked as **draft** because the maintainer wanted to first confirm
whether the stack is spec-compliant before deciding which knobs to ship;
this PR documents the investigation (stack is compliant), and surfaces
an opt-in recovery policy that addresses the field symptom without
changing the default behaviour. Convert to ready-for-review once the
design intent is acknowledged.

## Related Issues

- Fixes #3540

## 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.

---------

Co-authored-by: marcschier <marc.schier@github.com>
2026-06-07 17:38:58 +02:00
Marc Schier 49305d9085 V2 subscription engine close gap for test and feature parity with classic engine (#3824)
# Description

V2 subscription engine feature parity round to make the classic engine
eligible for deprecation. Splits the test surface so the classic and V2
engines can evolve independently, ports the gaps the classic-engine
integration tests had been exercising, and lands the public V2 API
additions needed to close them.

- Splits `Tests/Opc.Ua.Subscriptions.Tests` into a classic
(`Opc.Ua.Subscriptions.Classic.Tests`) and a V2
(`Opc.Ua.Subscriptions.Tests`) project to shrink CI time and let the two
engines diverge cleanly.
- Adds the V2 public-surface gaps required by the test ports
(`Subscription.ServerId` on the class, `SetSubscriptionDurableAsync`,
`SendInitialValuesOnTransfer`, unified `OnSubscriptionStateChangedAsync`
handler callback, per-item `ConditionRefreshAsync`, fluent
`LoadSubscriptionsAsync(Stream, …)` and `Subscription.Snapshot()` /
`RestoreAsync()` for save/load + transfer).
- Lands handler-centric design (no `PublishingStopped` property handlers
maintain derived state); always-sequential per-subscription delivery
documented + tested.
- **Adds short and long haul stability tests for the V2 `ManagedSession`
+ subscription engine. Closes #3744** (see "Issue #3744 Haul tests"
below).
- **Migrates SubscriptionStateSnapshot / MonitoredItemStateSnapshot to
`[DataType]` source-generator codecs**.
- `SubscriptionDurableV2Tests.cs` 5 V2 ports of the classic durable test
patterns.
- `V2FollowUpCoverageTests.cs` handler state-change callback, fluent
stream-based `LoadSubscriptionsAsync`, `SendInitialValuesOnTransfer`,
snapshot edge cases (empty / `DataChangeFilter` round-trip / concurrent
  mutation).
- `SubscriptionFailoverV2Tests.cs` forced channel-break with and without
`WithTransferSubscriptionsOnRecreate`.
- `MonitoredItemConditionRefreshLiveV2Tests.cs` ΓÇö live
`ConditionRefresh` against the reference server's event source; asserts
`RefreshStart` / `RefreshEnd` events flow through the handler.

## Fixes

- #3744 Haul tests (V2 ManagedSession + subscription engine)
`Tests/Opc.Ua.Sessions.Tests/ManagedSessionStabilityTest.cs` adds the
short/long haul coverage requested by
[#3744](https://github.com/OPCFoundation/UA-.NETStandard/issues/3744)
plus the bonus fault-injection variant:

| Test | Duration | Category | Purpose |
|---|---|---|---|
| `ShortHaulManagedSessionV2Async` | 2 minutes | `ManagedSessionHaul`
(`[Explicit]`) | Quick local sanity check of the V2 monotonicity
contract. |
| `LongHaulManagedSessionV2Async` | 90 minutes (configurable via
`TEST_DURATION_MINUTES`) | `ManagedSessionHaul` (`[Explicit]`) |
Long-running V2 stability + monotonicity. |
| `LongHaulManagedSessionWithFaultInjectionV2Async` | 90 minutes
(configurable) + fault every `FAULT_INJECTION_INTERVAL_SECONDS` (default
60s) | `ManagedSessionHaul` (`[Explicit]`) | **Bonus** ΓÇö force-closes
the subscriber transport channel periodically; verifies V2 manager
transfers/recreates the subscription and continues monotonic delivery
across reconnects. |

**Pattern.** A writer `ManagedSession` increments a `uint32` counter and
writes it into `Scalar_Static_Mass_UInt32_UInt32_00` every 250ms. A
subscriber `ManagedSession` runs a V2 subscription with a single
monitored item on the same node. `MonotonicCounterHandler` asserts each
received sample is *strictly greater than* the previous one. V2
`ISubscriptionNotificationHandler` per-subscription ordering guarantee.
Skipped values (sampling rate < write rate) are tolerated; duplicates
and reorderings are violations.
2026-06-03 04:39:08 +02:00
Marc Schier bd4543e961 ManagedSession, Pluggable Subscription engine, and fluent builder + DI (#3730)
- 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.
2026-05-05 19:09:07 +02:00
Marc Schier 26a0b21881 Replace session state encoder with IEncodable generation using source generators (#3673)
* Replace SessionStateEncoder with IEncodeable on session/subscription models

- Source-gen [DataType]/[DataTypeField] on: MonitoredItemOptions, MonitoredItemState,
  SubscriptionOptions, SubscriptionState (auto-generated Encode/Decode/IsEqual/Clone)
- Manual IEncodeable on: SessionOptions, SessionState, SessionConfiguration
  (ConfiguredEndpoint and IUserIdentity require manual encoding)
- Delete SessionStateEncoder.cs (488 lines removed)
- Remove [DataContract]/[DataMember]/[KnownType]/[CollectionDataContract] attributes
- Remove JsonSerializerContext classes
- Change init -> set, byte[] -> ByteString, DateTime -> DateTimeUtc
- MonitoredItems: ArrayOf<MonitoredItemState> with StructureHandling.Inline
- Subscriptions: ArrayOf<SubscriptionState>

* Source generator: support partial init properties with backing fields

Add IsInitOnly detection to the [DataType] source generator so that
partial properties with init-only setters can be used in IEncodeable types.

For each init-only partial property, the generator:
- Emits a private backing field (__PropertyName)
- Emits the partial property implementation (get => __field; init => __field = value)
- Uses the backing field in Decode() instead of the property
- Skips simple init-only fields in Clone() (record 'with' already copies them)
Detection uses both IPropertySymbol.SetMethod.IsInitOnly and syntax-tree
fallback (SyntaxKind.InitAccessorDeclaration) for partial definitions.
* docs: add partial init properties and session state migration sections

- SourceGeneratedDataTypes.md: new 'Partial Init Properties' section
  documenting backing field generation for init-only partial properties
- MigrationGuide.md: new 'Session State Persistence' section covering
2026-04-19 13:39:01 +02:00
Marc Schier 2960388560 Update headers and license files (#3388)
Update license headers to copy right year 2025, replace RCL/GPL headers with MIT, replace the nuget license with MIT (via license expression).
2025-12-04 19:44:40 +01:00
Marc Schier 1c178402ad Refactor client state persistence and add more tests (#3303)
* State handling and better serialization
* Nullable for almost everything  inclient library
* Additional testing of session
2025-11-01 17:18:48 +01:00