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feat: replace debug view polling with real-time SignalR streaming

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The debug view polled every 2s by re-subscribing for full snapshots. Now a
persistent DebugStreamBridgeActor on central subscribes once and receives
incremental Akka stream events from the site, forwarding them to the Blazor
component via callbacks and to the CLI via a new SignalR hub at
/hubs/debug-stream. Adds `debug stream` CLI command with auto-reconnect.
This commit is contained in:
Joseph Doherty
2026-03-21 01:34:53 -04:00
parent d91aa83665
commit fd2e96fea2
15 changed files with 777 additions and 75 deletions
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19
docs/requirements/Component-Communication.md
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@@ -50,15 +50,22 @@ Both central and site clusters. Each side has communication actors that handle m
- Site applies and acknowledges.
### 6. Debug Streaming (Site → Central)
- **Pattern**: Subscribe/stream with initial snapshot.
- Central sends a subscribe request for a specific instance (identified by unique name).
- Site requests a **snapshot** of all current attribute values and alarm states from the Instance Actor and sends it to central.
- Site then subscribes to the **site-wide Akka stream** filtered by the instance's unique name and forwards attribute value changes and alarm state changes to central.
- **Pattern**: Subscribe/push with initial snapshot (no polling).
- A **DebugStreamBridgeActor** (one per active debug session) is created on the central cluster by the **DebugStreamService**. The bridge actor sends a `SubscribeDebugViewRequest` to the site via `CentralCommunicationActor`, with itself as the `Sender`. The site's `InstanceActor` registers the bridge actor as the debug subscriber.
- Site requests a **snapshot** of all current attribute values and alarm states from the Instance Actor and sends it to the bridge actor.
- Site then subscribes to the **site-wide Akka stream** filtered by the instance's unique name and forwards `AttributeValueChanged` and `AlarmStateChanged` events to the bridge actor in real time via Akka remoting.
- The bridge actor forwards received events to the consumer via callbacks (Blazor component or SignalR hub).
- Attribute value stream messages: `[InstanceUniqueName].[AttributePath].[AttributeName]`, value, quality, timestamp.
- Alarm state stream messages: `[InstanceUniqueName].[AlarmName]`, state (active/normal), priority, timestamp.
- Central sends an unsubscribe request when the debug view closes. The site removes its stream subscription.
- Central sends an unsubscribe request when the debug session ends. The site removes its stream subscription and the bridge actor is stopped.
- The stream is session-based and temporary.
#### Central-Side Debug Stream Components
- **DebugStreamService**: Singleton service that manages debug stream sessions. Resolves instance ID to unique name and site, creates and tears down `DebugStreamBridgeActor` instances, and provides a clean API for both Blazor components and the SignalR hub.
- **DebugStreamBridgeActor**: One per active debug session. Acts as the Akka-level subscriber registered with the site's `InstanceActor`. Receives real-time `AttributeValueChanged` and `AlarmStateChanged` events from the site and forwards them to the consumer via callbacks.
- **DebugStreamHub**: SignalR hub at `/hubs/debug-stream` for external consumers (e.g., CLI). Authenticates via Basic Auth + LDAP and requires the **Deployment** role. Server-to-client methods: `OnSnapshot`, `OnAttributeChanged`, `OnAlarmChanged`, `OnStreamTerminated`.
### 6a. Debug Snapshot (Central → Site)
- **Pattern**: Request/Response (one-shot, no subscription).
- Central sends a `DebugSnapshotRequest` (identified by instance unique name) to the site.
@@ -159,7 +166,7 @@ The ManagementActor is registered at the well-known path `/user/management` on c
## Connection Failure Behavior
- **In-flight messages**: When a connection drops while a request is in flight (e.g., deployment sent but no response received), the Akka ask pattern times out and the caller receives a failure. There is **no automatic retry or buffering at central** — the engineer sees the failure in the UI and re-initiates the action. This is consistent with the design principle that central does not buffer messages.
- **Debug streams**: Any connection interruption (failover or network blip) kills the debug stream. The engineer must reopen the debug view in the Central UI to re-establish the subscription with a fresh snapshot. There is no auto-resume.
- **Debug streams**: Any connection interruption (failover or network blip) kills the debug stream. The `DebugStreamBridgeActor` is stopped and the consumer is notified via `OnStreamTerminated`. The engineer must reopen the debug view to re-establish the subscription with a fresh snapshot. There is no auto-resume.
## Failover Behavior