prometheus/node_exporter · error

couldn't get IOPPowerSourcesList

Error message

couldn't get IOPPowerSourcesList: %w

What it means

The Darwin power supply collector's Update calls getPowerSourceList(), which wraps IOKit's IOPSCopyPowerSourcesInfo/IOPSCopyPowerSourcesList. When that IOKit call fails, the error is wrapped as "couldn't get IOPPowerSourcesList". This means the collector could not enumerate the machine's power sources (battery/AC) via IOKit, so no power metrics can be reported for this scrape.

Solutions

1. Run the collector outside sandbox/container restrictions so it can talk to IOKit power services (host access, not virtualized).
2. Check that macOS power management is functioning (pmset -g batt works for the same user).
3. If the host has no queryable power sources, disable the powersupply collector instead of treating the scrape as failed.

Example fix

// before
node_exporter --collector.powersupply  # inside a container
// after
node_exporter --collector.powersupply  # run directly on the macOS host

// Update already returns the wrapped error; treat it as a failed scrape.
if err := coll.Update(ch); err != nil {
	if isPowerSourceUnavailable(err) {
		logger.Warn("power sources unavailable; skipping powersupply collection", "err", err)
		return nil
	}
	return err
}

When it happens

Trigger: Update -> getPowerSourceList returning an error, i.e. IOPSCopyPowerSourcesList failing or returning nil on macOS — typically when the process lacks entitlement/sandbox access to IOKit power services or IOKit returns no power sources handle.

Common situations: Running node_exporter inside a sandbox/container on macOS where IOKit power APIs are restricted; running in CI VMs without battery/power-source services; IOKit returning NULL under unusual system states.

Understand the failure class

Background: "API request failed": what wrapped HTTP errors from external APIs mean and how to find the real cause — this error's family across 29 libraries.

Related errors

• could not get power_supply class info
• no CPU power status has been recorded
• invalid flag value
• error obtaining power_supply class info
• failed to open procfs

AI-assisted analysis of prometheus/node_exporter@17ddd77c59 (2026-09-07). Data as JSON: /api/errors/8f2430846a29a2bd. Report an issue: GitHub.

Appendix: source

Thrown at collector/powersupplyclass_darwin.go:193

    free(ps->InternalFailure);
    free(ps->IsPresent);

    free(ps);
}
*/
import "C"

import (
	"fmt"
	"strconv"

	"github.com/prometheus/client_golang/prometheus"
)

func (c *powerSupplyClassCollector) Update(ch chan<- prometheus.Metric) error {
	psList, err := getPowerSourceList()
	if err != nil {
		return fmt.Errorf("couldn't get IOPPowerSourcesList: %w", err)
	}

	for _, info := range psList {
		labels := getPowerSourceDescriptorLabels(info)
		powerSupplyName := labels["power_supply"]

		if c.ignoredPattern.MatchString(powerSupplyName) {
			continue
		}

		for name, value := range getPowerSourceDescriptorMap(info) {
			if value == nil {
				continue
			}

			ch <- prometheus.MustNewConstMetric(
				prometheus.NewDesc(
					prometheus.BuildFQName(namespace, c.subsystem, name),

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