chore(stcrashreceiver): metrics on ignore matches

Signed-off-by: Jakob Borg <jakob@kastelo.net>

cmd/infra/stcrashreceiver/main.go

@@ -123,7 +123,8 @@ func handleFailureFn(dsn, failureDir string, ignore *ignorePatterns) func(w http
 			return
 		}
 
-		if _, ok := ignore.match(bs); ok {
+		if pat, ok := ignore.match(bs); ok {
+			metricIgnoreMatchesTotal.WithLabelValues(pat).Inc()
 			result = "ignored"
 			return
 		}

cmd/infra/stcrashreceiver/metrics.go

@@ -42,4 +42,9 @@ var (
 		Subsystem: "crashreceiver",
 		Name:      "sentry_reports_total",
 	}, []string{"result"})
+	metricIgnoreMatchesTotal = promauto.NewCounterVec(prometheus.CounterOpts{
+		Namespace: "syncthing",
+		Subsystem: "crashreceiver",
+		Name:      "ignore_matches_total",
+	}, []string{"pattern"})
 )

cmd/infra/stcrashreceiver/stcrashreceiver.go

@@ -90,6 +90,7 @@ func (r *crashReceiver) servePut(reportID string, w http.ResponseWriter, req *ht
 	first := string(bytes.TrimSpace(bytes.Split(bs, []byte("\n"))[0]))
 
 	if pat, ok := r.ignore.match(bs); ok {
+		metricIgnoreMatchesTotal.WithLabelValues(pat).Inc()
 		result = "ignored"
 		log.Printf("Ignored report %s, matched: %s (%s)", reportID[:8], pat, first)
 		return