grafana/k6 · error

metrics push concurrency must be a positive number but is %d

Error message

metrics push concurrency must be a positive number but is %d

What it means

The cloud output was configured with K6_CLOUD_METRIC_PUSH_CONCURRENCY (or options.cloud metricPushConcurrency) below 1. newOutput validates that the number of concurrent metric-pushing goroutines is at least 1 and rejects zero/negative values.

Source

Thrown at internal/output/cloud/output.go:182

		scriptPath := params.ScriptPath.String()
		if scriptPath == "" {
			// Script from stdin without a name, likely from stdin
			return nil, errors.New("script name not set, please specify K6_CLOUD_NAME or options.cloud.name")
		}

		conf.Name = null.StringFrom(filepath.Base(scriptPath))
	}
	if conf.Name.String == "-" {
		conf.Name = null.StringFrom(defaultTestName)
	}

	duration, testEnds := lib.GetEndOffset(params.ExecutionPlan)
	if !testEnds {
		return nil, errors.New("tests with unspecified duration are not allowed when outputting data to k6 cloud")
	}

	if conf.MetricPushConcurrency.Int64 < 1 {
		return nil, fmt.Errorf("metrics push concurrency must be a positive number but is %d",
			conf.MetricPushConcurrency.Int64)
	}

	if conf.MaxTimeSeriesInBatch.Int64 < 1 {
		return nil, fmt.Errorf("max allowed number of time series in a single batch must be a positive number but is %d",
			conf.MaxTimeSeriesInBatch.Int64)
	}

	apiClient := cloudapi.NewClient(
		logger, conf.Token.String, conf.Host.String, build.Version, conf.Timeout.TimeDuration())

	return &Output{
		config:        conf,
		client:        apiClient,
		executionPlan: params.ExecutionPlan,
		duration:      int64(duration / time.Second),
		logger:        logger,
		usage:         params.Usage,

View on GitHub (pinned to 01ffac6f24)

Solutions

1. Set metricPushConcurrency to a positive integer, e.g. K6_CLOUD_METRIC_PUSH_CONCURRENCY=5
2. Omit the setting to use the default concurrency

When it happens

Trigger: Thrown at internal/output/cloud/output.go:182 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/06e2961287a6833a. Report an issue: GitHub.