# Description
This pull request introduces a scalable consumer task model for the
`MonitoredNode2` class, optimizing the handling of event notifications
for notifier nodes. Any notifier node can opt into (or out of) dynamic
scaling of consumer tasks based on the number of event monitored items,
improving throughput and responsiveness under high event loads. The
Server node (`ObjectIds.Server`) is always auto-opted-in. The
implementation includes safe scaling up and down of consumers, robust
disposal logic, Fluent API integration, and tests to verify correct
delivery of events.
**Scalable consumer task management:**
* Added an `enableMultipleEventConsumers` constructor parameter to
`MonitoredNode2` that enables dynamic scaling of consumer tasks to match
the number of event monitored items. The Server node
(`ObjectIds.Server`) always auto-opts-in regardless of this parameter.
* Added `AllowMultipleEventConsumers(NodeId, bool enable = true)`
protected method on `AsyncCustomNodeManager` with an internal
`MultiConsumerNodeIds` registry, so any node manager can
programmatically opt in or out specific nodes.
* Added `IsMultipleEventConsumerNode(NodeId)` to the `IAsyncNodeManager`
interface, allowing consumers to query multi-consumer opt-in status
through the interface without casting to `AsyncCustomNodeManager`.
* Both `MonitoredNodeMonitoredItemManager` and
`SamplingGroupMonitoredItemManager` use the `IAsyncNodeManager`
interface method when creating `MonitoredNode2` instances.
**Fluent API integration:**
* Added `AllowMultipleEventConsumers(bool enable = true)` method to
`INodeBuilder` and its `NodeBuilder` implementation, allowing any
notifier node to be opted in or out via the fluent builder pipeline
(e.g. `builder.Node("myNotifier").AllowMultipleEventConsumers()`).
* The `NodeManagerBuilder` routes the registration to the owning
`AsyncCustomNodeManager`'s multi-consumer registry, supporting both
opt-in and opt-out.
**Testing and verification:**
* Added unit tests to verify multi-consumer behavior for both Server
node (auto-opt-in) and non-Server nodes (explicit opt-in), as well as
default single-consumer behavior for nodes without opt-in.
* Fixed race condition in permission cache tests
(`OnMonitoredNodeChanged_DefaultPermissionsChanged_CacheInvalidated` and
`InvalidatePermissionCacheForSession` tests) that caused flaky CI
failures. The tests now signal on `QueueValue` (which fires after the
cache is populated) instead of `ValidateRolePermissionsAsync` (which
fires before), ensuring cache invalidation operates on a populated
cache.
## Related Issues
## 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 my fix is effective or that my
feature works and increased code coverage.
- [ ] 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.
- [x] I fixed **all** failing and flaky tests in the CI pipelines and
**all** CodeQL warnings.
- [x] I have addressed **all** PR feedback received.
---------
Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
* Add SessionActivated notification to invalidate permission caches on identity change
* Fix code review: rename test methods to PascalCase, use default instead of new ValueTask()
* Improve comment clarity in AsyncCustomNodeManager.SessionActivatedAsync
* Add integration test for permission re-evaluation after TransferSubscriptions + ActivateSession
* Replace integration test to use restricted RolePermissions node and verify permission denial after re-activation
* Extract HasDataChangeNotificationForClientHandle helper to reduce duplication
* Use Interfaces Introduced with 1.5.378
Refactor to use interfaces for node managers and server
Replaced concrete types with interfaces (e.g., IMasterNodeManager, ICoreNodeManager, IDiagnosticsNodeManager, IConfigurationNodeManager, IServerBase) across method signatures, properties, and internal structures to improve abstraction and flexibility.
* Refactor CoreNodeManager to be Based on CustomNodeManager2
* Add Test
* Add INodeManager3 with role permission validation
Introduce INodeManager3 interface extending INodeManager2, adding synchronous role permission validation methods. Update all node manager interfaces and classes to use INodeManager3. Extend IAsyncNodeManager with async permission validation methods and update adapters for sync/async bridging. Deprecate FindNodeInAddressSpace in favor of new async FindNodeInAddressSpaceAsync. Refactor MonitoredNode2 to use thread-safe collections and locking for monitored items. Enhance event reporting with security and permission checks. Update constructors and documentation to reflect new interfaces and best practices.
* Implement AsyncCustomNodeManager
* fix comment
* fix
* Add tests
* fix
* Implement better locking strategy
* fix
* Add more tests
* Add tests
* Add tests
* Add Tests
* cleanup
* cleanup
* Add tests that verifies for AnalogItemState the instrument range is checked brefore writing
* only assign new NodeID in default factory if NodeId isNull
* Run all tests also with sampling groups
* Add Docs
* cleanup
* Add chaos test
* fix test
* Use AsyncCustomNodeManager for ReferenceNodeManger & imrpove ReadAttributes method of NodeState
* fixes
* fixes and code review comments
* Use Interfaces Introduced with 1.5.378
Refactor to use interfaces for node managers and server
Replaced concrete types with interfaces (e.g., IMasterNodeManager, ICoreNodeManager, IDiagnosticsNodeManager, IConfigurationNodeManager, IServerBase) across method signatures, properties, and internal structures to improve abstraction and flexibility.
* Refactor CoreNodeManager to be Based on CustomNodeManager2
* Add Test
* Add INodeManager3 with role permission validation
Introduce INodeManager3 interface extending INodeManager2, adding synchronous role permission validation methods. Update all node manager interfaces and classes to use INodeManager3. Extend IAsyncNodeManager with async permission validation methods and update adapters for sync/async bridging. Deprecate FindNodeInAddressSpace in favor of new async FindNodeInAddressSpaceAsync. Refactor MonitoredNode2 to use thread-safe collections and locking for monitored items. Enhance event reporting with security and permission checks. Update constructors and documentation to reflect new interfaces and best practices.
* Implement AsyncCustomNodeManager
* fix comment
* fix
* Add tests
* fix
* Implement better locking strategy
* fix
* Add more tests
* Add tests
* Add tests
* Add Tests
* cleanup
* cleanup
* Add tests that verifies for AnalogItemState the instrument range is checked brefore writing
* only assign new NodeID in default factory if NodeId isNull
* Run all tests also with sampling groups
* Add Docs
* cleanup
* Add chaos test
* fix test
* Use Interfaces Introduced with 1.5.378
Refactor to use interfaces for node managers and server
Replaced concrete types with interfaces (e.g., IMasterNodeManager, ICoreNodeManager, IDiagnosticsNodeManager, IConfigurationNodeManager, IServerBase) across method signatures, properties, and internal structures to improve abstraction and flexibility.
* Refactor CoreNodeManager to be Based on CustomNodeManager2
* Add Test
* Add INodeManager3 with role permission validation
Introduce INodeManager3 interface extending INodeManager2, adding synchronous role permission validation methods. Update all node manager interfaces and classes to use INodeManager3. Extend IAsyncNodeManager with async permission validation methods and update adapters for sync/async bridging. Deprecate FindNodeInAddressSpace in favor of new async FindNodeInAddressSpaceAsync. Refactor MonitoredNode2 to use thread-safe collections and locking for monitored items. Enhance event reporting with security and permission checks. Update constructors and documentation to reflect new interfaces and best practices.
* fix comment
* fix
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