From 745195d56a98a1ae6bcdf1518a9190eb504e9e5e Mon Sep 17 00:00:00 2001
From: Hector <dev@hsmith.org>
Date: Mon, 30 Aug 2021 08:02:32 +0100
Subject: [PATCH] new metric with error counts

Add a new metric to track the number of errors found while connecting to
the fail2ban socket.
---
 src/exporter.go              | 29 +++++++++++++++++++++++++++++
 src/socket/fail2banSocket.go |  1 -
 2 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/src/exporter.go b/src/exporter.go
index da6468c..81d30cf 100644
--- a/src/exporter.go
+++ b/src/exporter.go
@@ -50,6 +50,11 @@ var (
 		[]string{"type"}, nil,
 	)
 
+	metricErrorCountNew = prometheus.NewDesc(
+		prometheus.BuildFQName(sockNamespace, "", "errors"),
+		"Number of errors found since startup",
+		[]string{"type"}, nil,
+	)
 	metricServerUp = prometheus.NewDesc(
 		prometheus.BuildFQName(sockNamespace, "", "up"),
 		"Check if the fail2ban server is up",
@@ -87,6 +92,8 @@ type Exporter struct {
 	socketPath   string
 	lastError    error
 	dbErrorCount int
+	socketConnectionErrorCount int
+	socketRequestErrorCount  int
 }
 
 func (e *Exporter) Describe(ch chan<- *prometheus.Desc) {
@@ -105,6 +112,7 @@ func (e *Exporter) Describe(ch chan<- *prometheus.Desc) {
 		ch <- metricJailBannedCurrent
 		ch <- metricJailBannedTotal
 	}
+	ch <- metricErrorCountNew
 }
 
 func (e *Exporter) Collect(ch chan<- prometheus.Metric) {
@@ -119,6 +127,7 @@ func (e *Exporter) Collect(ch chan<- prometheus.Metric) {
 		s, err := socket.ConnectToSocket(e.socketPath)
 		if err != nil {
 			log.Printf("error opening socket: %v", err)
+			e.socketConnectionErrorCount++
 		} else {
 			defer s.Close()
 		}
@@ -127,6 +136,7 @@ func (e *Exporter) Collect(ch chan<- prometheus.Metric) {
 			e.collectJailMetrics(ch, s)
 		}
 	}
+	e.collectErrorCountMetricNew(ch)
 }
 
 func (e *Exporter) collectUpMetric(ch chan<- prometheus.Metric) {
@@ -193,10 +203,25 @@ func (e *Exporter) collectEnabledJailMetrics(ch chan<- prometheus.Metric) {
 	}
 }
 
+func (e *Exporter) collectErrorCountMetricNew(ch chan<- prometheus.Metric) {
+	ch <- prometheus.MustNewConstMetric(
+		metricErrorCountNew, prometheus.CounterValue, float64(e.dbErrorCount), "db",
+	)
+	ch <- prometheus.MustNewConstMetric(
+		metricErrorCountNew, prometheus.CounterValue, float64(e.socketConnectionErrorCount), "socket_conn",
+	)
+	ch <- prometheus.MustNewConstMetric(
+		metricErrorCountNew, prometheus.CounterValue, float64(e.socketRequestErrorCount), "socket_req",
+	)
+}
+
 func (e *Exporter) collectServerUpMetric(ch chan<- prometheus.Metric, s *socket.Fail2BanSocket) {
 	var serverUp float64 = 0
 	if s != nil {
 		pingSuccess, err := s.Ping()
+		if err != nil {
+			e.socketRequestErrorCount++
+		}
 		if err == nil && pingSuccess {
 			serverUp = 1
 		}
@@ -209,6 +234,9 @@ func (e *Exporter) collectServerUpMetric(ch chan<- prometheus.Metric, s *socket.
 func (e *Exporter) collectJailMetrics(ch chan<- prometheus.Metric, s *socket.Fail2BanSocket) {
 	jails, err := s.GetJails()
 	var count float64 = 0
+	if err != nil {
+		e.socketRequestErrorCount++
+	}
 	if err == nil {
 		count = float64(len(jails))
 	}
@@ -224,6 +252,7 @@ func (e *Exporter) collectJailMetrics(ch chan<- prometheus.Metric, s *socket.Fai
 func (e *Exporter) collectJailStatsMetric(ch chan<- prometheus.Metric, s *socket.Fail2BanSocket, jail string) {
 	stats, err := s.GetJailStats(jail)
 	if err != nil {
+		e.socketRequestErrorCount++
 		log.Printf("failed to get stats for jail %s: %v", jail, err)
 		return
 	}
diff --git a/src/socket/fail2banSocket.go b/src/socket/fail2banSocket.go
index 589217c..3ff95de 100644
--- a/src/socket/fail2banSocket.go
+++ b/src/socket/fail2banSocket.go
@@ -4,7 +4,6 @@ import (
 	"fmt"
 	"github.com/kisielk/og-rek"
 	"github.com/nlpodyssey/gopickle/types"
-	"log"
 	"net"
 	"strings"
 )