func()

in collector/receiver/prometheusreceiver/metrics_receiver.go [254:317]
52 lines of code
8 McCabe index (conditional complexity)

func (r *pReceiver) initPrometheusComponents(ctx context.Context, logger log.Logger, host component.Host) error {
	// Some SD mechanisms use the "refresh" package, which has its own metrics.
	refreshSdMetrics := discovery.NewRefreshMetrics(r.registerer)

	// Register the metrics specific for each SD mechanism, and the ones for the refresh package.
	sdMetrics, err := discovery.RegisterSDMetrics(r.registerer, refreshSdMetrics)
	if err != nil {
		return fmt.Errorf("failed to register service discovery metrics: %w", err)
	}
	r.discoveryManager = discovery.NewManager(ctx, logger, r.registerer, sdMetrics, discovery.SkipInitialWait())
	if r.discoveryManager == nil {
		// NewManager can sometimes return nil if it encountered an error, but
		// the error message is logged separately.
		return fmt.Errorf("failed to create discovery manager")
	}

	go func() {
		r.settings.Logger.Info("Starting discovery manager")
		if err := r.discoveryManager.Run(); err != nil {
			r.settings.Logger.Error("Discovery manager failed", zap.Error(err))
			componentstatus.ReportStatus(host, componentstatus.NewFatalErrorEvent(err))
		}
	}()

	var startTimeMetricRegex *regexp.Regexp
	if r.cfg.AdjusterOpts.StartTimeMetricRegex != "" {
		var err error
		startTimeMetricRegex, err = regexp.Compile(r.cfg.AdjusterOpts.StartTimeMetricRegex)
		if err != nil {
			return err
		}
	}

	store, err := internal.NewAppendable(
		r.consumer,
		r.settings,
		gcInterval(r.cfg.PrometheusConfig),
		r.cfg.AdjusterOpts.UseStartTimeMetric,
		startTimeMetricRegex,
		useCreatedMetricGate.IsEnabled(),
		r.cfg.AdjusterOpts.UseCollectorStartTimeFallback,
		r.cfg.AdjusterOpts.AllowCumulativeResets,
		r.cfg.PrometheusConfig.GlobalConfig.ExternalLabels,
		r.cfg.TrimMetricSuffixes,
	)
	if err != nil {
		return err
	}

	// For the sidecar, use a 10s offset from the start before scraping the targets.
	tenSecondOffSet := 10 * time.Second
	r.scrapeManager, err = scrape.NewManager(&scrape.Options{PassMetadataInContext: true, InitialScrapeOffset: &tenSecondOffSet, DiscoveryReloadOnStartup: true}, logger, store, r.registerer)
	if err != nil {
		return err
	}

	go func() {
		// The scrape manager needs to wait for the configuration to be loaded before beginning
		<-r.configLoaded
		r.settings.Logger.Info("Starting scrape manager")
		r.scrapeManager.Run(r.discoveryManager.SyncCh())
	}()
	return nil
}