End-to-end data path is now wired on the read side: driver subscriptions
fire AttributeValuePublished → DriverHostActor → DependencyMuxActor →
DependencyValueChanged to every interested VirtualTagActor. Previously
the publish hit a dead-letter at the host.
DependencyMuxActor:
- Per-node fan-out router. Maintains tagRef → Set<IActorRef> with a
reverse subscriber → refs index so unregister/replace are O(refs).
- Watches subscribers; Terminated triggers automatic unregister so
dead virtual-tag actors stop receiving publishes.
- Re-register replaces the prior interest set — no stale-ref leaks
on actor restart.
- Drops publishes for refs with no interested subscribers.
VirtualTagActor:
- New Props params: dependencyRefs + mux ActorRef.
- PreStart sends RegisterInterest to the mux; PostStop sends
UnregisterInterest. Default both null so older callers stay quiet.
DriverHostActor:
- New dependencyMux Props param. Steady + Applying states now
receive AttributeValuePublished from their DriverInstance children
and forward to the mux. Null mux is a no-op (dev/Mac).
ServiceCollectionExtensions:
- WithOtOpcUaRuntimeActors spawns DependencyMuxActor before
DriverHostActor and threads its ActorRef into the host's Props.
New DependencyMuxActorKey + DependencyMuxActorName.
Tests: Runtime 57 -> 63 (+6):
- Mux forwards to only subscribers interested in each ref
- Publish for unregistered ref is dropped silently
- Unregister stops forwarding
- Re-register replaces prior interest set
- VirtualTagActor PreStart registration drives end-to-end eval
(uses AwaitAssert to race-safely settle the PreStart Tell)
- DriverHostActor forwards AttributeValuePublished through to mux
All 6 v2 test suites green: 163 tests passing.
F8 (#79) state updated — dep subscribe seam shipped, Core.VirtualTags
production engine binding (compile + ITagUpstreamSource subscribe) is
the residual.
DriverHostActor.ApplyAndAck now reads the deployment artifact and
reconciles its set of DriverInstanceActor children — spawn the missing,
ApplyDelta to those with changed config, stop the removed/disabled.
The diff lives in pure DriverSpawnPlanner so it can be unit-tested
without an ActorSystem.
Adds IDriverFactory in Core.Abstractions (consumed by Runtime) +
DriverFactoryRegistryAdapter in Core.Hosting that wraps the existing
v1 DriverFactoryRegistry — Runtime stays decoupled from Polly/Serilog,
the Host wires the adapter once driver assemblies have registered.
ShouldStub(type, roles) is now actually called on every spawn — Galaxy
+ Wonderware-Historian boot stubbed on macOS/Linux or whenever the host
carries the dev role. Missing factory ⇒ stub fallback, never a crash.
Tests: 24 → 34 in Runtime (+10):
- DriverSpawnPlannerTests x7 (diff cases, type change ⇒ stop+respawn)
- DeploymentArtifactTests x5 (empty/malformed/missing fields tolerant)
- DriverHostActorReconcileTests x4 (spawn count, stub fallback,
ShouldStub gate, second-apply stops the removed)
All 6 v2 test suites green: 120 tests passing.
Closes F20 (ShouldStub wired). F7 marked partial — subscription
publishing + write path still stubbed in DriverInstanceActor itself.
- New Commons.Messages.Fleet.GetDiagnostics request record.
- DriverHostActor handles GetDiagnostics in all three states (Steady, Applying,
Stale); replies with a NodeDiagnosticsSnapshot built from _currentRevision
+ the local NodeId. Drivers list is empty until F7 wires the per-instance
children.
- FleetDiagnosticsClient now resolves the target via ActorSelection at
akka.tcp://{system}@{nodeId}/user/driver-host and Asks with a 3s timeout.
On timeout/peer-down it returns an empty snapshot so the UI degrades
gracefully rather than throwing.
Two new integration tests in Host.IntegrationTests:
- GetDiagnostics_returns_snapshot_with_target_NodeId verifies the
cross-node Ask/Reply works.
- GetDiagnostics_after_deploy_reports_current_revision exercises the
end-to-end path: AdminOps starts a deployment, both DriverHostActors
apply, then diagnostics reports the new revision on both nodes.
All 98 v2 tests pass (was 96 + 2 new).
DeployHappyPathTests exercises the full deploy pipeline on the 2-node harness:
AdminOperationsActor → ConfigPublishCoordinator → DistributedPubSub →
DriverHostActor on both nodes → ApplyAck → coordinator seals. Verifies both
NodeDeploymentState rows reach Applied and Deployment.Status reaches Sealed.
Exposed + fixed two production bugs along the way:
1. Coordinator was publishing DispatchDeployment on the "deployments" topic but
never subscribed to anything — DriverHostActor ACKs published on the same
topic could not reach it. Added dedicated "deployment-acks" topic with
coordinator subscription in PreStart, and DriverHostActor publishes ACKs
there.
2. NodeId derivation used member.Address.Host only — two cluster members on a
shared loopback host (test harness, dev VMs) collided to one identity. The
coordinator's expected-ack set became {1} and the system sealed after only
half the nodes acked. Switched to host:port everywhere (ClusterRoleInfo +
coordinator) so loopback nodes stay distinct and production identities are
harmlessly more specific.
Tests: 95 v2 tests pass (was 93 + 2 deploy tests), 0 skipped.
Failover scenarios (design §8 cases 3-7: node-kill-mid-apply, split-brain,
restart-during-deploy) deferred — they need controlled node-down primitives
on the harness. Tracked as F22 (failover scenario test cases).
Joseph Doherty