From e6b7e5908112d61a209433a4c99915b98d4dbaf8 Mon Sep 17 00:00:00 2001
From: Hector <dev@hsmith.org>
Date: Mon, 30 Aug 2021 07:48:18 +0100
Subject: [PATCH] set the up metric to 0 if the socket connection fails

---
 src/exporter.go | 22 +++++++++++++---------
 1 file changed, 13 insertions(+), 9 deletions(-)

diff --git a/src/exporter.go b/src/exporter.go
index 007fb51..54adc6d 100644
--- a/src/exporter.go
+++ b/src/exporter.go
@@ -50,7 +50,7 @@ var (
 		[]string{"type"}, nil,
 	)
 
-	metricServerPing = prometheus.NewDesc(
+	metricServerUp = prometheus.NewDesc(
 		prometheus.BuildFQName(sockNamespace, "", "up"),
 		"Check if the fail2ban server is up",
 		nil, nil,
@@ -98,7 +98,7 @@ func (e *Exporter) Describe(ch chan<- *prometheus.Desc) {
 		ch <- metricErrorCount
 	}
 	if e.socketPath != "" {
-		ch <- metricServerPing
+		ch <- metricServerUp
 		ch <- metricJailCount
 		ch <- metricJailFailedCurrent
 		ch <- metricJailFailedTotal
@@ -121,7 +121,9 @@ func (e *Exporter) Collect(ch chan<- prometheus.Metric) {
 			log.Printf("error opening socket: %v", err)
 		} else {
 			defer s.Close()
-			e.collectServerPingMetric(ch, s)
+		}
+		e.collectServerUpMetric(ch, s)
+		if err == nil && s != nil {
 			e.collectJailMetrics(ch, s)
 		}
 	}
@@ -191,14 +193,16 @@ func (e *Exporter) collectEnabledJailMetrics(ch chan<- prometheus.Metric) {
 	}
 }
 
-func (e *Exporter) collectServerPingMetric(ch chan<- prometheus.Metric, s *socket.Fail2BanSocket) {
-	pingSuccess := s.Ping()
-	var pingSuccessInt float64 = 1
-	if !pingSuccess {
-		pingSuccessInt = 0
+func (e *Exporter) collectServerUpMetric(ch chan<- prometheus.Metric, s *socket.Fail2BanSocket) {
+	var serverUp float64 = 0
+	if s != nil {
+		pingSuccess := s.Ping()
+		if pingSuccess {
+			serverUp = 1
+		}
 	}
 	ch <- prometheus.MustNewConstMetric(
-		metricServerPing, prometheus.GaugeValue, pingSuccessInt,
+		metricServerUp, prometheus.GaugeValue, serverUp,
 	)
 }