chore(communication): low-severity cleanup — eviction counting, shared ingest timeout, split app heartbeat interval, doc notes

2026-07-08 21:54:42 -04:00
parent 11c72ecf0f
commit 846279f6a8
7 changed files with 63 additions and 21 deletions
@@ -64,6 +64,8 @@ Both central and site clusters. Each side has communication actors that handle m
 - Alarm state stream messages: `[InstanceUniqueName].[AlarmName]`, state (active/normal), priority, timestamp.
 - Central sends an unsubscribe request via ClusterClient when the debug session ends. The gRPC stream is cancelled. The site's `StreamRelayActor` is stopped and the SiteStreamManager subscription is removed.
 - The stream is session-based and temporary.
+- **Accepted limitation (central-side session locality):** debug sessions are process-local state on the central node hosting the `DebugStreamBridgeActor`. A central **restart or failover drops all active sessions** with no `OnStreamTerminated` signal to the operator — the engineer simply re-establishes the debug session from the UI. Debug streaming is an interactive, transient diagnostic aid, so this is an accepted trade-off rather than a durability gap (arch review 02, U7).
+- **Backpressure is lossy-by-design and now observable:** the per-session `Channel<SiteStreamEvent>` (bounded 1000, `DropOldest`) silently evicts the oldest event when a slow consumer falls behind. The eviction is counted via the channel's `itemDropped` callback and logged at Warning (first eviction, then every 500th) so real event loss on a debug stream is visible instead of silent.

 #### Site-Side gRPC Streaming Components