func ExposePrometheusCollectorHealthMetrics()

in otelcollector/fluent-bit/src/prometheus_collector_health.go [89:147]
47 lines of code
4 McCabe index (conditional complexity)

func ExposePrometheusCollectorHealthMetrics() {

	// A new registry excludes go_* and promhttp_* metrics for the endpoint
	r := prometheus.NewRegistry()
	r.MustRegister(timeseriesReceivedMetric)
	r.MustRegister(timeseriesSentMetric)
	r.MustRegister(bytesSentMetric)
	r.MustRegister(invalidCustomConfigMetric)
	r.MustRegister(exportingFailedMetric)

	handler := promhttp.HandlerFor(r, promhttp.HandlerOpts{})
	http.Handle("/metrics", handler)

	go func() {
		TimeseriesVolumeTicker = time.NewTicker(time.Second * time.Duration(prometheusCollectorHealthInterval))
		lastTickerStart := time.Now()
		
		for ; true; <-TimeseriesVolumeTicker.C {
			elapsed := time.Since(lastTickerStart)
			timePassedInMinutes := (float64(elapsed) / float64(time.Second)) / float64(prometheusCollectorHealthInterval)

			TimeseriesVolumeMutex.Lock()
			timeseriesReceivedRate := math.Round(TimeseriesReceivedTotal / timePassedInMinutes)
			timeseriesSentRate := math.Round(TimeseriesSentTotal / timePassedInMinutes)
			bytesSentRate := math.Round(BytesSentTotal / timePassedInMinutes)

			timeseriesReceivedMetric.With(prometheus.Labels{"computer":CommonProperties["computer"], "release":CommonProperties["helmreleasename"], "controller_type":CommonProperties["controllertype"]}).Set(timeseriesReceivedRate)
			timeseriesSentMetric.With(prometheus.Labels{"computer":CommonProperties["computer"], "release":CommonProperties["helmreleasename"], "controller_type":CommonProperties["controllertype"]}).Set(timeseriesSentRate)
			bytesSentMetric.With(prometheus.Labels{"computer":CommonProperties["computer"], "release":CommonProperties["helmreleasename"], "controller_type":CommonProperties["controllertype"]}).Set(bytesSentRate)
		
			TimeseriesReceivedTotal = 0.0
			TimeseriesSentTotal = 0.0
			BytesSentTotal = 0.0
			TimeseriesVolumeMutex.Unlock()

			isInvalidCustomConfig := 0
			invalidConfigErrorString := ""
			if os.Getenv("AZMON_INVALID_CUSTOM_PROMETHEUS_CONFIG") == "true" {
				isInvalidCustomConfig = 1
				invalidConfigErrorString = os.Getenv("INVALID_CONFIG_FATAL_ERROR")
			}
			invalidCustomConfigMetric.With(prometheus.Labels{"computer":CommonProperties["computer"], "release":CommonProperties["helmreleasename"], "controller_type":CommonProperties["controllertype"], "error":invalidConfigErrorString}).Set(float64(isInvalidCustomConfig))
		
			ExportingFailedMutex.Lock()
			exportingFailedMetric.With(prometheus.Labels{"computer":CommonProperties["computer"], "release":CommonProperties["helmreleasename"], "controller_type":CommonProperties["controllertype"]}).Add(float64(OtelCollectorExportingFailedCount))
			OtelCollectorExportingFailedCount = 0
			ExportingFailedMutex.Unlock()

			lastTickerStart = time.Now()
		}
	}()

	err := http.ListenAndServe(prometheusCollectorHealthPort, nil)
	if err != nil {
		Log("Error for Prometheus Collector Health endpoint: %s", err.Error())
		exception := appinsights.NewExceptionTelemetry(err.Error())
		TelemetryClient.Track(exception)
	}
}