grafana/k6 · error

metric '%s' does not exist in the script

Error message

metric '%s' does not exist in the script

What it means

A threshold (or submetric) was defined in the test options for a metric name that is not present in the metric registry. getThresholdMetricOrSubmetric splits the name at '{' and looks up the base metric name; the lookup returned nil, meaning no metric with that name was ever emitted or registered.

Source

Thrown at internal/metrics/engine/engine.go:69

	return me, nil
}

// CreateIngester returns a pseudo-Output that uses the given metric samples to
// update the engine's inner state.
func (me *MetricsEngine) CreateIngester() *OutputIngester {
	return &OutputIngester{
		logger:        me.logger.WithField("component", "metrics-engine-ingester"),
		metricsEngine: me,
		cardinality:   newCardinalityControl(),
	}
}

func (me *MetricsEngine) getThresholdMetricOrSubmetric(name string) (*metrics.Metric, error) {
	metricDefinition, submetricDefinition, _ := strings.Cut(name, "{")

	metric := me.registry.Get(metricDefinition)
	if metric == nil {
		return nil, fmt.Errorf("metric '%s' does not exist in the script", metricDefinition)
	}

	if len(submetricDefinition) == 0 { // no sub-metric
		return metric, nil
	}

	if submetricDefinition[len(submetricDefinition)-1] != '}' {
		return nil, fmt.Errorf("missing ending bracket, sub-metric format needs to be 'metric{key:value}'")
	}
	sm, err := metric.AddSubmetric(submetricDefinition[:len(submetricDefinition)-1])
	if err != nil {
		return nil, err
	}

	if sm.Metric.Observed {
		// Do not repeat warnings for the same sub-metrics
		return sm.Metric, nil
	}

View on GitHub (pinned to 01ffac6f24)

Solutions

1. Fix the metric name spelling in options.thresholds
2. Register/emit the metric (e.g. via a custom Trend/Counter/Rate/Gauge or by enabling the relevant built-in metric)
3. Remove the threshold for the nonexistent metric

When it happens

Trigger: Thrown at internal/metrics/engine/engine.go:69 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of grafana/k6@01ffac6f24 (2026-08-18). Data as JSON: /api/errors/5256ee6e6b34d5fa. Report an issue: GitHub.