Merge pull request #162 from prometheus/grobie/reduce-indentation

Break out event handling into its own function

exporter.go

@@ -253,6 +253,8 @@ func escapeMetricName(metricName string) string {
 	return metricName
 }
 
+// Listen handles all events sent to the given channel sequentially. It
+// terminates when the channel is closed.
 func (b *Exporter) Listen(e <-chan Events) {
 	for {
 		events, ok := <-e
@@ -261,24 +263,29 @@ func (b *Exporter) Listen(e <-chan Events) {
 			return
 		}
 		for _, event := range events {
-			var help string
-			metricName := ""
-			prometheusLabels := event.Labels()
+			b.handleEvent(event)
+		}
+	}
+}
 
+// handleEvent processes a single Event according to the configured mapping.
+func (b *Exporter) handleEvent(event Event) {
 	mapping, labels, present := b.mapper.GetMapping(event.MetricName(), event.MetricType())
 	if mapping == nil {
 		mapping = &mapper.MetricMapping{}
 	}
 
 	if mapping.Action == mapper.ActionTypeDrop {
-				continue
+		return
 	}
 
-			if mapping.HelpText == "" {
-				help = defaultHelp
-			} else {
+	help := defaultHelp
+	if mapping.HelpText != "" {
 		help = mapping.HelpText
 	}
+
+	metricName := ""
+	prometheusLabels := event.Labels()
 	if present {
 		metricName = escapeMetricName(mapping.Name)
 		for label, value := range labels {
@@ -296,7 +303,7 @@ func (b *Exporter) Listen(e <-chan Events) {
 		if event.Value() < 0.0 {
 			log.Debugf("Counter %q is: '%f' (counter must be non-negative value)", metricName, event.Value())
 			eventStats.WithLabelValues("illegal_negative_counter").Inc()
-					continue
+			return
 		}
 
 		counter, err := b.Counters.Get(
@@ -381,8 +388,6 @@ func (b *Exporter) Listen(e <-chan Events) {
 		log.Debugln("Unsupported event type")
 		eventStats.WithLabelValues("illegal").Inc()
 	}
-		}
-	}
 }
 
 func NewExporter(mapper *mapper.MetricMapper) *Exporter {