NatureWhistle.EventHandler (nature_whistle v0.3.0)

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Telemetry event handler for NatureWhistle.

This module is the hot path of the library. It is called directly by :telemetry whenever a configured event is emitted, so the code here is kept intentionally small and defensive:

  • locate the alerts configured for the event
  • read the measurement specified by measurement_key
  • compare the measurement to the alert threshold
  • apply rate-limit and sliding-window suppression
  • transition the alert into a breached state if delivery is allowed

Any exception is rescued and logged so alert processing never crashes the host application.

Summary

Functions

handle_event(event, measurements, metadata, config)

Handles a single telemetry event.

Functions

handle_event(event, measurements, metadata, config)

Handles a single telemetry event.

Parameters:

  • event - the telemetry event name, for example [:vm, :memory, :total]
  • measurements - the telemetry measurement map
  • metadata - arbitrary metadata emitted with the event
  • _config - telemetry callback config, currently unused

The function is designed to be called by :telemetry.attach/4. It performs all alert evaluation for that event and quietly returns :ok when no alert is configured or no threshold is crossed.