Merge pull request #7 from wikimedia/silent

Allow to silence "error handling stats line" messages

exporter.go

@@ -171,24 +171,37 @@ func (re *rsyslogExporter) Collect(ch chan<- prometheus.Metric) {
 			continue
 		}
 
+		labelValues := []string{}
+		if p.promLabelValue() != "" {
+			labelValues = []string{p.promLabelValue()}
+		}
 		metric := prometheus.MustNewConstMetric(
 			p.promDescription(),
 			p.promType(),
 			p.promValue(),
-			p.promLabelValue(),
+			labelValues...,
 		)
 
 		ch <- metric
 	}
 }
 
-func (re *rsyslogExporter) run() {
+func (re *rsyslogExporter) run(silent bool) {
+	errorPoint := &point{
+		Name:        "stats_line_errors",
+		Type:        counter,
+		Description: "Counts errors during stats line handling",
+	}
+	re.set(errorPoint)
 	for re.scanner.Scan() {
 		err := re.handleStatLine(re.scanner.Bytes())
 		if err != nil {
+			errorPoint.Value += 1
+			if !silent {
 				log.Printf("error handling stats line: %v, line was: %s", err, re.scanner.Bytes())
 			}
 		}
+	}
 	if err := re.scanner.Err(); err != nil {
 		log.Printf("error reading input: %v", err)
 	}

fixtures/rsyslog-stats.log

 2017-08-30T08:09:54.776051+00:00 some-node.example.org rsyslogd-pstats: { "name": "global", "origin": "dynstats", "values": { } }
+2017-08-30T08:09:54.776052+00:00 some-node.example.org rsyslogd-pstats: { "name": "global", "origin": "percentile", "values": { } }
 2017-08-30T08:09:54.776072+00:00 some-node.example.org rsyslogd-pstats: { "name": "imuxsock", "origin": "imuxsock", "submitted": 9, "ratelimit.discarded": 0, "ratelimit.numratelimiters": 0 }
 2017-08-30T08:09:54.776082+00:00 some-node.example.org rsyslogd-pstats: { "name": "action 0", "origin": "core.action", "processed": 0, "failed": 0, "suspended": 0, "suspended.duration": 0, "resumed": 0 }
 2017-08-30T08:09:54.776088+00:00 some-node.example.org rsyslogd-pstats: { "name": "to_exporter_2", "origin": "core.action", "processed": 0, "failed": 0, "suspended": 0, "suspended.duration": 0, "resumed": 0 }

main.go

@@ -17,6 +17,7 @@ var (
 	metricPath    = flag.String("web.telemetry-path", "/metrics", "Path under which to expose metrics.")
 	certPath      = flag.String("tls.server-crt", "", "Path to PEM encoded file containing TLS server cert.")
 	keyPath       = flag.String("tls.server-key", "", "Path to PEM encoded file containing TLS server key (unencyrpted).")
+	silent        = flag.Bool("silent", false, "Disable logging of errors in handling stats lines")
 )
 
 func main() {
@@ -37,7 +38,7 @@ func main() {
 	}()
 
 	go func() {
-		exporter.run()
+		exporter.run(*silent)
 	}()
 
 	prometheus.MustRegister(exporter)

point.go

@@ -23,10 +23,14 @@ type point struct {
 }
 
 func (p *point) promDescription() *prometheus.Desc {
+	variableLabels := []string{}
+	if p.promLabelName() != "" {
+		variableLabels = []string{p.promLabelName()}
+	}
 	return prometheus.NewDesc(
 		prometheus.BuildFQName("", "rsyslog", p.Name),
 		p.Description,
-		[]string{p.promLabelName()},
+		variableLabels,
 		nil,
 	)
 }