slimtoolkit/slim · error

composite monitor failed: %w

Error message

composite monitor failed: %w

What it means

After the monitor completes, processMonitoringResults calls mon.Status() to collect the composite monitor report. If Status() returns an error, it is logged and wrapped with this message. This means the monitor could not produce a valid status/report.

Source

Thrown at pkg/app/sensor/controlled/controlled.go:245

	return s.processMonitoringResults(mon)
}

func (s *Sensor) processMonitoringResults(mon monitor.CompositeMonitor) error {
	// A bit of code duplication to avoid starting a goroutine
	// for error event handling - keeping the control flow
	// "single-threaded" keeps reasoning about the logic.
	for _, err := range mon.DrainErrors() {
		log.WithError(err).Warn("sensor: non-critical monitor error condition (drained)")
		s.exe.PubEvent(event.Error, monitor.NonCriticalError(err).Error())
	}

	log.Info("sensor: composite monitor is done, checking status...")

	report, err := mon.Status()
	if err != nil {
		log.WithError(err).Error("sensor: composite monitor failed")
		return fmt.Errorf("composite monitor failed: %w", err)
	}

	if err := s.artifactor.Process(
		mon.StartCommand(),
		s.mountPoint,
		report.PeReport,
		report.FanReport,
		report.PtReport,
	); err != nil {
		log.WithError(err).Error("sensor: artifact.Process() failed")
		return fmt.Errorf("saving reports failed: %w", err)
	}
	return nil // Clean exit
}

View on GitHub (pinned to 81940d17fa)

Solutions

1. Inspect the wrapped error and individual sub-monitor states for the root cause
2. Check monitor logs for which sub-monitor failed
3. Ensure the monitor was started correctly and had sufficient resources (memory, file descriptors)

err := sensor.Run(ctx)
if err != nil && strings.Contains(err.Error(), "composite monitor failed") {
	// inspect sub-monitor states / logs before retry
}

When it happens

Trigger: processMonitoringResults (called from runWithMonitor) invokes mon.Status() and the composite monitor reports failure — e.g. one of its sub-monitors errored or its internal state is invalid.

Common situations: Sub-monitor (PE/fan/Pt) crash mid-run, monitor timeout, corrupted monitor state after resource exhaustion.

Related errors

• run sensor without monitor failed: %w
• run sensor with monitor failed: %w
• failed to prepare artifacts env: %w
• saving reports failed: %w
• sensor shutdown before monitor stop

AI-assisted analysis of slimtoolkit/slim@81940d17fa (2026-08-31). Data as JSON: /api/errors/ccc3049febf31cc8. Report an issue: GitHub.