func()

in collector/scraper.go [216:287]
60 lines of code
14 McCabe index (conditional complexity)

func (s *Scraper) scrapeTargets(ctx context.Context) {
	targets := s.Targets()

	scrapeTime := time.Now().UnixNano() / 1e6
	wr := prompb.WriteRequestPool.Get()
	defer prompb.WriteRequestPool.Put(wr)

	for _, target := range targets {
		logger.Infof("Scraping %s", target.String())
		iter, err := s.scrapeClient.FetchMetricsIterator(target.Addr)
		if err != nil {
			logger.Warnf("Failed to create scrape iterator %s/%s/%s at %s: %s",
				target.Namespace, target.Pod, target.Container, target.Addr, err.Error())
			continue
		}
		for iter.Next() {
			pt := prompb.TimeSeriesPool.Get()
			ts, err := iter.TimeSeriesInto(pt)
			if err != nil {
				logger.Warnf("Failed to parse series %s/%s/%s at %s: %s",
					target.Namespace, target.Pod, target.Container, target.Addr, err.Error())
				continue
			}

			name := prompb.MetricName(ts)
			if s.requestTransformer.ShouldDropMetric(ts, name) {
				prompb.TimeSeriesPool.Put(ts)
				metrics.MetricsDroppedTotal.WithLabelValues(string(name)).Add(1)
				continue
			}

			for i, s := range ts.Samples {
				if s.Timestamp == 0 {
					s.Timestamp = scrapeTime
				}
				ts.Samples[i] = s
			}

			if target.Namespace != "" {
				ts.AppendLabelString("adxmon_namespace", target.Namespace)
			}

			if target.Pod != "" {
				ts.AppendLabelString("adxmon_pod", target.Pod)
			}

			if target.Container != "" {
				ts.AppendLabelString("adxmon_container", target.Container)
			}

			prompb.Sort(ts.Labels)

			ts = s.requestTransformer.TransformTimeSeries(ts)
			wr.Timeseries = append(wr.Timeseries, ts)
			wr = s.flushBatchIfNecessary(ctx, wr)
		}
		if err := iter.Err(); err != nil {
			logger.Warnf("Failed to scrape %s/%s/%s at %s: %s", target.Namespace, target.Pod, target.Container, target.Addr, err.Error())
		}

		if err := iter.Close(); err != nil {
			logger.Errorf("Failed to close iterator for %s/%s/%s: %s", target.Namespace, target.Pod, target.Container, err.Error())
		}

		wr = s.flushBatchIfNecessary(ctx, wr)
	}

	if err := s.sendBatch(ctx, wr); err != nil {
		logger.Errorf(err.Error())
	}
	wr.Timeseries = wr.Timeseries[:0]
}