3.2 KiB
3.2 KiB
Component: Site Event Logging
Purpose
The Site Event Logging component records operational events at each site cluster, providing a local audit trail of runtime activity. Events are queryable from the central UI for remote troubleshooting.
Location
Site clusters (event recording and storage). Central cluster (remote query access via UI).
Responsibilities
- Record operational events from all site subsystems.
- Persist events to local SQLite.
- Enforce 30-day retention policy with automatic purging.
- Respond to remote queries from central for event log data.
Events Logged
| Category | Events |
|---|---|
| Script Executions | Script started, completed, failed (with error details), recursion limit exceeded |
| Alarm Events | Alarm activated, alarm cleared (which alarm, which instance), alarm evaluation error |
| Deployment Events | Configuration received from central, scripts compiled, applied successfully, apply failed |
| Data Connection Status | Connected, disconnected, reconnected (per connection) |
| Store-and-Forward | Message queued, delivered, retried, parked |
| Instance Lifecycle | Instance enabled, disabled, deleted |
Event Entry Schema
Each event entry contains:
- Timestamp: When the event occurred.
- Event Type: Category of the event (script, alarm, deployment, connection, store-and-forward, instance-lifecycle).
- Severity: Info, Warning, or Error.
- Instance ID (optional): The instance associated with the event (if applicable).
- Source: The subsystem that generated the event (e.g., "ScriptActor:MonitorSpeed", "AlarmActor:OverTemp", "DataConnection:PLC1").
- Message: Human-readable description of the event.
- Details (optional): Additional structured data (e.g., exception stack trace, alarm name, message ID, compilation errors).
Storage
- Events are stored in local SQLite on each site node.
- Each node maintains its own event log (the active node generates events; the standby node generates minimal events related to replication).
- Retention: 30 days. A background job automatically purges events older than 30 days.
Central Access
- The central UI can query site event logs remotely via the Communication Layer.
- Queries support filtering by:
- Event type / category
- Time range
- Instance ID
- Severity
- The site processes the query locally and returns matching results to central.
Dependencies
- SQLite: Local storage on each site node.
- Communication Layer: Handles remote query requests from central.
- Site Runtime: Generates script execution events, alarm events, deployment application events, and instance lifecycle events.
- Data Connection Layer: Generates connection status events.
- Store-and-Forward Engine: Generates buffer activity events.
Interactions
- All site subsystems: Event logging is a cross-cutting concern — any subsystem that produces notable events calls the Event Logging service.
- Communication Layer: Receives remote queries from central and returns results.
- Central UI: Site Event Log Viewer displays queried events.
- Health Monitoring: Script error rates and alarm evaluation error rates can be derived from event log data.