Method innerHandler

node_exporter.go:127–180

innerHandler is used to create both the one unfiltered http.Handler to be wrapped by the outer handler and also the filtered handlers created on the fly. The former is accomplished by calling innerHandler without any arguments (in which case it will log all the collectors enabled via command-line fl

(filters ...string)

// (in which case it will log all the collectors enabled via command-line
// flags).
func (h *handler) innerHandler(filters ...string) (http.Handler, error) {
	nc, err := collector.NewNodeCollector(h.logger, filters...)
	if err != nil {
		return nil, fmt.Errorf("couldn't create collector: %s", err)
	}

	// Only log the creation of an unfiltered handler, which should happen
	// only once upon startup.
	if len(filters) == 0 {
		h.logger.Info("Enabled collectors")
		for n := range nc.Collectors {
			h.enabledCollectors = append(h.enabledCollectors, n)
		}
		sort.Strings(h.enabledCollectors)
		for _, c := range h.enabledCollectors {
			h.logger.Info(c)
		}
	}

	r := prometheus.NewRegistry()
	r.MustRegister(versioncollector.NewCollector("node_exporter"))
	if err := r.Register(nc); err != nil {
		return nil, fmt.Errorf("couldn't register node collector: %s", err)
	}

	var handler http.Handler
	if h.includeExporterMetrics {
		handler = promhttp.HandlerFor(
			prometheus.Gatherers{h.exporterMetricsRegistry, r},
			promhttp.HandlerOpts{
				ErrorLog:            slog.NewLogLogger(h.logger.Handler(), slog.LevelError),
				ErrorHandling:       promhttp.ContinueOnError,
				MaxRequestsInFlight: h.maxRequests,
				Registry:            h.exporterMetricsRegistry,
			},
		)
		// Note that we have to use h.exporterMetricsRegistry here to
		// use the same promhttp metrics for all expositions.
		handler = promhttp.InstrumentMetricHandler(
			h.exporterMetricsRegistry, handler,
		)
	} else {
		handler = promhttp.HandlerFor(
			r,
			promhttp.HandlerOpts{
				ErrorLog:            slog.NewLogLogger(h.logger.Handler(), slog.LevelError),
				ErrorHandling:       promhttp.ContinueOnError,
				MaxRequestsInFlight: h.maxRequests,
			},
		)
	}

	return handler, nil
}

func main() {
	var (