how prometheus Metric to text

[aixeshunter]

Hi, I want to output the metrics from file not http in telegraf, but I have no idea how to convert the data.

I get the metric with type prometheus.Metric, how convert to byte/string?

	for name, family := range s.fam {
		// Get list of all labels on MetricFamily
		var labelNames []string
		for k, v := range family.LabelSet {
			if v > 0 {
				labelNames = append(labelNames, k)
			}
		}
		desc := prometheus.NewDesc(name, "Telegraf collected metric", labelNames, nil)

		for _, sample := range family.Samples {
			// Get labels for this sample; unset labels will be set to the
			// empty string
			var labels []string
			for _, label := range labelNames {
				v := sample.Labels[label]
				labels = append(labels, v)
			}

			var metric prometheus.Metric
			var err error
			switch family.TelegrafValueType {
			case telegraf.Summary:
				metric, err = prometheus.NewConstSummary(desc, sample.Count, sample.Sum, sample.SummaryValue, labels...)
			case telegraf.Histogram:
				metric, err = prometheus.NewConstHistogram(desc, sample.Count, sample.Sum, sample.HistogramValue, labels...)
			default:
				metric, err = prometheus.NewConstMetric(desc, getPromValueType(family.TelegrafValueType), sample.Value, labels...)
			}
			if err != nil {
				log.Printf("E! Error creating prometheus metric, "+
					"key: %s, labels: %v,\nerr: %s\n",
					name, labels, err.Error())
			}

			if s.ExportTimestamp {
				metric = prometheus.NewMetricWithTimestamp(sample.Timestamp, metric)
			}

I find the func MetricFamilyToText(out io.Writer, in *dto.MetricFamily) (written int, err error) in prometheus/common/expfmt/text_create.go, but how it works?

[brian-brazil]

It makes more sense to ask questions like this on the prometheus-users mailing list rather than in a GitHub issue. On the mailing list, more people are available to potentially respond to your question, and the whole community can benefit from the answers provided.