Method collectMetrics

modules/generator/registry/histogram.go:177–247

(appender storage.Appender, timeMs int64)

}

func (h *histogram) collectMetrics(appender storage.Appender, timeMs int64) error {
	h.seriesMtx.Lock()
	defer h.seriesMtx.Unlock()

	for _, s := range h.series {
		// If we are about to call Append for the first time on a series,
		// we need to first insert a 0 value to allow Prometheus to start from a non-null value.
		if s.isNew() {
			// We set the timestamp of the init serie at the end of the previous minute, that way we ensure it ends in a
			// different aggregation interval to avoid be downsampled.
			endOfLastMinuteMs := getEndOfLastMinuteMs(timeMs)
			_, err := appender.Append(0, s.countLabels, endOfLastMinuteMs, 0)
			if err != nil && !isOutOfOrderError(err) {
				return err
			}
		}

		// sum
		_, err := appender.Append(0, s.sumLabels, timeMs, s.sum.Load())
		if err != nil {
			return err
		}

		// count
		_, err = appender.Append(0, s.countLabels, timeMs, s.count.Load())
		if err != nil {
			return err
		}

		// bucket
		for i := range h.bucketLabels {
			if s.isNew() {
				endOfLastMinuteMs := getEndOfLastMinuteMs(timeMs)
				_, err = appender.Append(0, s.bucketLabels[i], endOfLastMinuteMs, 0)
				if err != nil && !isOutOfOrderError(err) {
					return err
				}
			}
			ref, err := appender.Append(0, s.bucketLabels[i], timeMs, s.buckets[i].Load())
			if err != nil {
				return err
			}

			ex := s.exemplars[i].Load()
			if ex != "" {

				lbls := []labels.Label{{
					Name:  h.traceIDLabelName,
					Value: ex,
				}}

				_, err = appender.AppendExemplar(ref, s.bucketLabels[i], exemplar.Exemplar{
					Labels: labels.New(lbls...),
					Value:  s.exemplarValues[i].Load(),
					Ts:     timeMs,
				})
				if err != nil {
					return err