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Observability

Language: δΈ­ζ–‡

Event Model

SupervisorEvent describes one lifecycle fact. It contains When, Where, What, sequence, and correlation identifier.

When records wall-clock time, monotonic time, uptime, generation, and attempt. Where records supervisor path, child identifier, parent identifier, and task name. What records state transition, policy decision, health state, exit reason, or control command.

Pipeline Outputs

The observability pipeline publishes the same lifecycle fact as these signals:

  • SupervisorEvent.
  • Structured log.
  • Tracing span and tracing event.
  • Metrics.
  • Audit event.
  • Event journal entry.
  • Test recorder entry.

Metric Labels

Metric labels must stay low-cardinality. Acceptable labels include supervisor path, child identifier, state, decision, and failure category. Full error text, user input, and unbounded dynamic values should not become labels.

Real Shutdown Pipeline

After ShutdownTree runs the real shutdown pipeline, the observability pipeline must surface lifecycle facts for each stage. ChildShutdownCancelDelivered means the runtime delivered CancellationToken to the in-flight child attempt. ChildShutdownGraceful means the child task returned inside the graceful drain budget. ChildShutdownAborted means the runtime requested abort for a stuck task. ChildShutdownLateReport means the child task returned after the normal shutdown accounting window. ShutdownCompleted means the pipeline emitted the final reconcile report.

Metrics record shutdown facts with low-cardinality labels. supervisor_shutdown_duration_seconds measures full pipeline duration. supervisor_shutdown_child_outcomes_total counts outcomes by status and phase and must not place child_id on metric labels. supervisor_shutdown_abort_total counts abort paths by bounded reason. supervisor_shutdown_late_reports_total counts late reports by phase.

Audit events record cancel delivered, graceful outcome, abort outcome, late report, and completed reconcile. When the core runtime does not own the dashboard IPC socket, the reconcile report records socket status as NotOwned.

Diagnostic Replay

The event journal stores a fixed number of recent events. RunSummary is built from the event journal, current state, and policy decisions so operators can explain meltdown, shutdown timeout, or parent escalation.