docs: update changelog for release

Update changelog

See merge request hectorjsmith/fail2ban-prometheus-exporter!36

CHANGELOG.md

@@ -5,6 +5,15 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog], and this project adheres to [Semantic Versioning].
 
 ## [Unreleased]
+*Nothing yet*
+
+## [0.3.0] - 2021-09-27
+*Export new version metrics ([#12](https://gitlab.com/hectorjsmith/fail2ban-prometheus-exporter/issues/12))*
+
+### Added
+- (3c9a005) feat: render basic html page at root url
+- (22a165d) feat: improve startup logging
+- (fba9ee2) feat: export new version metric ([#12](https://gitlab.com/hectorjsmith/fail2ban-prometheus-exporter/issues/12))
 
 ## [0.2.0] - 2021-08-31
 *Collect metrics through fail2ban socket - based on [#11](https://gitlab.com/hectorjsmith/fail2ban-prometheus-exporter/issues/11)*
@@ -39,6 +48,7 @@ The format is based on [Keep a Changelog], and this project adheres to [Semantic
 - (0842419) fix: compile tool without cgo_enabled flag
 
 ## 0.0.0 - 2021-02-05
+*Repository creation*
 
 ---
 
@@ -47,3 +57,4 @@ The format is based on [Keep a Changelog], and this project adheres to [Semantic
 [Unreleased]: https://gitlab.com/hectorjsmith/fail2ban-prometheus-exporter/compare/0.1.0...main
 [0.1.0]: https://gitlab.com/hectorjsmith/fail2ban-prometheus-exporter/compare/0.0.0...0.1.0
 [0.2.0]: https://gitlab.com/hectorjsmith/fail2ban-prometheus-exporter/compare/0.1.0...0.2.0
+[0.3.0]: https://gitlab.com/hectorjsmith/fail2ban-prometheus-exporter/compare/0.2.0...0.3.0

src/export/build.go

@@ -0,0 +1,25 @@
+package export
+
+import (
+	"fail2ban-prometheus-exporter/cfg"
+	fail2banDb "fail2ban-prometheus-exporter/db"
+	"log"
+)
+
+func NewExporter(appSettings *cfg.AppSettings, exporterVersion string) *Exporter {
+	exporter := &Exporter{
+		exporterVersion:            exporterVersion,
+		lastError:                  nil,
+		dbErrorCount:               0,
+		socketConnectionErrorCount: 0,
+		socketRequestErrorCount:    0,
+	}
+	if appSettings.Fail2BanDbPath != "" {
+		log.Print("database-based metrics have been deprecated and will be removed in a future release")
+		exporter.db = fail2banDb.MustConnectToDb(appSettings.Fail2BanDbPath)
+	}
+	if appSettings.Fail2BanSocketPath != "" {
+		exporter.socketPath = appSettings.Fail2BanSocketPath
+	}
+	return exporter
+}

src/export/database.go

@@ -0,0 +1,102 @@
+package export
+
+import (
+	"github.com/prometheus/client_golang/prometheus"
+	"log"
+)
+
+const (
+	deprecatedNamespace = "fail2ban"
+)
+
+var (
+	deprecatedMetricUp = prometheus.NewDesc(
+		prometheus.BuildFQName(deprecatedNamespace, "", "up"),
+		"(Deprecated) Was the last fail2ban query successful.",
+		nil, nil,
+	)
+	deprecatedMetricBannedIpsPerJail = prometheus.NewDesc(
+		prometheus.BuildFQName(deprecatedNamespace, "", "banned_ips"),
+		"(Deprecated) Number of banned IPs stored in the database (per jail).",
+		[]string{"jail"}, nil,
+	)
+	deprecatedMetricBadIpsPerJail = prometheus.NewDesc(
+		prometheus.BuildFQName(deprecatedNamespace, "", "bad_ips"),
+		"(Deprecated) Number of bad IPs stored in the database (per jail).",
+		[]string{"jail"}, nil,
+	)
+	deprecatedMetricEnabledJails = prometheus.NewDesc(
+		prometheus.BuildFQName(deprecatedNamespace, "", "enabled_jails"),
+		"(Deprecated) Enabled jails.",
+		[]string{"jail"}, nil,
+	)
+	deprecatedMetricErrorCount = prometheus.NewDesc(
+		prometheus.BuildFQName(deprecatedNamespace, "", "errors"),
+		"(Deprecated) Number of errors found since startup.",
+		[]string{"type"}, nil,
+	)
+)
+
+func (e *Exporter) collectDeprecatedUpMetric(ch chan<- prometheus.Metric) {
+	var upMetricValue float64 = 1
+	if e.lastError != nil {
+		upMetricValue = 0
+	}
+	ch <- prometheus.MustNewConstMetric(
+		deprecatedMetricUp, prometheus.GaugeValue, upMetricValue,
+	)
+}
+
+func (e *Exporter) collectDeprecatedErrorCountMetric(ch chan<- prometheus.Metric) {
+	ch <- prometheus.MustNewConstMetric(
+		deprecatedMetricErrorCount, prometheus.CounterValue, float64(e.dbErrorCount), "db",
+	)
+}
+
+func (e *Exporter) collectDeprecatedBadIpsPerJailMetrics(ch chan<- prometheus.Metric) {
+	jailNameToCountMap, err := e.db.CountBadIpsPerJail()
+	e.lastError = err
+
+	if err != nil {
+		e.dbErrorCount++
+		log.Print(err)
+	}
+
+	for jailName, count := range jailNameToCountMap {
+		ch <- prometheus.MustNewConstMetric(
+			deprecatedMetricBadIpsPerJail, prometheus.GaugeValue, float64(count), jailName,
+		)
+	}
+}
+
+func (e *Exporter) collectDeprecatedBannedIpsPerJailMetrics(ch chan<- prometheus.Metric) {
+	jailNameToCountMap, err := e.db.CountBannedIpsPerJail()
+	e.lastError = err
+
+	if err != nil {
+		e.dbErrorCount++
+		log.Print(err)
+	}
+
+	for jailName, count := range jailNameToCountMap {
+		ch <- prometheus.MustNewConstMetric(
+			deprecatedMetricBannedIpsPerJail, prometheus.GaugeValue, float64(count), jailName,
+		)
+	}
+}
+
+func (e *Exporter) collectDeprecatedEnabledJailMetrics(ch chan<- prometheus.Metric) {
+	jailNameToEnabledMap, err := e.db.JailNameToEnabledValue()
+	e.lastError = err
+
+	if err != nil {
+		e.dbErrorCount++
+		log.Print(err)
+	}
+
+	for jailName, count := range jailNameToEnabledMap {
+		ch <- prometheus.MustNewConstMetric(
+			deprecatedMetricEnabledJails, prometheus.GaugeValue, float64(count), jailName,
+		)
+	}
+}

src/export/exporter.go

@@ -0,0 +1,64 @@
+package export
+
+import (
+	fail2banDb "fail2ban-prometheus-exporter/db"
+	"fail2ban-prometheus-exporter/socket"
+	"github.com/prometheus/client_golang/prometheus"
+	"log"
+)
+
+type Exporter struct {
+	db                         *fail2banDb.Fail2BanDB
+	socketPath                 string
+	exporterVersion            string
+	lastError                  error
+	dbErrorCount               int
+	socketConnectionErrorCount int
+	socketRequestErrorCount    int
+}
+
+func (e *Exporter) Describe(ch chan<- *prometheus.Desc) {
+	if e.db != nil {
+		ch <- deprecatedMetricUp
+		ch <- deprecatedMetricBadIpsPerJail
+		ch <- deprecatedMetricBannedIpsPerJail
+		ch <- deprecatedMetricEnabledJails
+		ch <- deprecatedMetricErrorCount
+	}
+	if e.socketPath != "" {
+		ch <- metricServerUp
+		ch <- metricJailCount
+		ch <- metricJailFailedCurrent
+		ch <- metricJailFailedTotal
+		ch <- metricJailBannedCurrent
+		ch <- metricJailBannedTotal
+	}
+	ch <- metricErrorCount
+}
+
+func (e *Exporter) Collect(ch chan<- prometheus.Metric) {
+	if e.db != nil {
+		e.collectDeprecatedBadIpsPerJailMetrics(ch)
+		e.collectDeprecatedBannedIpsPerJailMetrics(ch)
+		e.collectDeprecatedEnabledJailMetrics(ch)
+		e.collectDeprecatedUpMetric(ch)
+		e.collectDeprecatedErrorCountMetric(ch)
+	}
+	if e.socketPath != "" {
+		s, err := socket.ConnectToSocket(e.socketPath)
+		if err != nil {
+			log.Printf("error opening socket: %v", err)
+			e.socketConnectionErrorCount++
+		} else {
+			defer s.Close()
+		}
+		e.collectServerUpMetric(ch, s)
+		if err == nil && s != nil {
+			e.collectJailMetrics(ch, s)
+		}
+		e.collectVersionMetric(ch, s)
+	} else {
+		e.collectVersionMetric(ch, nil)
+	}
+	e.collectErrorCountMetric(ch)
+}

src/export/socket.go

@@ -0,0 +1,140 @@
+package export
+
+import (
+	"fail2ban-prometheus-exporter/socket"
+	"github.com/prometheus/client_golang/prometheus"
+	"log"
+)
+
+const (
+	namespace = "f2b"
+)
+
+var (
+	metricErrorCount = prometheus.NewDesc(
+		prometheus.BuildFQName(namespace, "", "errors"),
+		"Number of errors found since startup",
+		[]string{"type"}, nil,
+	)
+	metricServerUp = prometheus.NewDesc(
+		prometheus.BuildFQName(namespace, "", "up"),
+		"Check if the fail2ban server is up",
+		nil, nil,
+	)
+	metricJailCount = prometheus.NewDesc(
+		prometheus.BuildFQName(namespace, "", "jail_count"),
+		"Number of defined jails",
+		nil, nil,
+	)
+	metricJailFailedCurrent = prometheus.NewDesc(
+		prometheus.BuildFQName(namespace, "", "jail_failed_current"),
+		"Number of current failures on this jail's filter",
+		[]string{"jail"}, nil,
+	)
+	metricJailFailedTotal = prometheus.NewDesc(
+		prometheus.BuildFQName(namespace, "", "jail_failed_total"),
+		"Number of total failures on this jail's filter",
+		[]string{"jail"}, nil,
+	)
+	metricJailBannedCurrent = prometheus.NewDesc(
+		prometheus.BuildFQName(namespace, "", "jail_banned_current"),
+		"Number of IPs currently banned in this jail",
+		[]string{"jail"}, nil,
+	)
+	metricJailBannedTotal = prometheus.NewDesc(
+		prometheus.BuildFQName(namespace, "", "jail_banned_total"),
+		"Total number of IPs banned by this jail (includes expired bans)",
+		[]string{"jail"}, nil,
+	)
+	metricVersionInfo = prometheus.NewDesc(
+		prometheus.BuildFQName(namespace, "", "version"),
+		"Version of the exporter and fail2ban server",
+		[]string{"exporter", "fail2ban"}, nil,
+	)
+)
+
+func (e *Exporter) collectErrorCountMetric(ch chan<- prometheus.Metric) {
+	ch <- prometheus.MustNewConstMetric(
+		metricErrorCount, prometheus.CounterValue, float64(e.dbErrorCount), "db",
+	)
+	ch <- prometheus.MustNewConstMetric(
+		metricErrorCount, prometheus.CounterValue, float64(e.socketConnectionErrorCount), "socket_conn",
+	)
+	ch <- prometheus.MustNewConstMetric(
+		metricErrorCount, 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++
+			log.Print(err)
+		}
+		if err == nil && pingSuccess {
+			serverUp = 1
+		}
+	}
+	ch <- prometheus.MustNewConstMetric(
+		metricServerUp, prometheus.GaugeValue, serverUp,
+	)
+}
+
+func (e *Exporter) collectJailMetrics(ch chan<- prometheus.Metric, s *socket.Fail2BanSocket) {
+	jails, err := s.GetJails()
+	var count float64 = 0
+	if err != nil {
+		e.socketRequestErrorCount++
+		log.Print(err)
+	}
+	if err == nil {
+		count = float64(len(jails))
+	}
+	ch <- prometheus.MustNewConstMetric(
+		metricJailCount, prometheus.GaugeValue, count,
+	)
+
+	for i := range jails {
+		e.collectJailStatsMetric(ch, s, jails[i])
+	}
+}
+
+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
+	}
+
+	ch <- prometheus.MustNewConstMetric(
+		metricJailFailedCurrent, prometheus.GaugeValue, float64(stats.FailedCurrent), jail,
+	)
+	ch <- prometheus.MustNewConstMetric(
+		metricJailFailedTotal, prometheus.GaugeValue, float64(stats.FailedTotal), jail,
+	)
+	ch <- prometheus.MustNewConstMetric(
+		metricJailBannedCurrent, prometheus.GaugeValue, float64(stats.BannedCurrent), jail,
+	)
+	ch <- prometheus.MustNewConstMetric(
+		metricJailBannedTotal, prometheus.GaugeValue, float64(stats.BannedTotal), jail,
+	)
+}
+
+func (e *Exporter) collectVersionMetric(ch chan<- prometheus.Metric, s *socket.Fail2BanSocket) {
+	var err error
+	var fail2banVersion = ""
+	if s != nil {
+		fail2banVersion, err = s.GetServerVersion()
+		if err != nil {
+			e.socketRequestErrorCount++
+			log.Printf("failed to get fail2ban server version: %v", err)
+		}
+	}
+
+	ch <- prometheus.MustNewConstMetric(
+		metricVersionInfo, prometheus.GaugeValue, float64(1), e.exporterVersion, fail2banVersion,
+	)
+}

src/exporter.go

@@ -2,8 +2,7 @@ package main
 
 import (
 	"fail2ban-prometheus-exporter/cfg"
-	fail2banDb "fail2ban-prometheus-exporter/db"
-	"fail2ban-prometheus-exporter/socket"
+	"fail2ban-prometheus-exporter/export"
 	"fmt"
 	"log"
 	"net/http"
@@ -14,8 +13,7 @@ import (
 )
 
 const (
-	deprecatedNamespace = "fail2ban"
-	namespace           = "f2b"
+	metricsPath = "/metrics"
 )
 
 var (
@@ -23,279 +21,51 @@ var (
 	commit  = "none"
 	date    = "unknown"
 	builtBy = "unknown"
-
-	deprecatedMetricUp = prometheus.NewDesc(
-		prometheus.BuildFQName(deprecatedNamespace, "", "up"),
-		"(Deprecated) Was the last fail2ban query successful.",
-		nil, nil,
-	)
-	deprecatedMetricBannedIpsPerJail = prometheus.NewDesc(
-		prometheus.BuildFQName(deprecatedNamespace, "", "banned_ips"),
-		"(Deprecated) Number of banned IPs stored in the database (per jail).",
-		[]string{"jail"}, nil,
-	)
-	deprecatedMetricBadIpsPerJail = prometheus.NewDesc(
-		prometheus.BuildFQName(deprecatedNamespace, "", "bad_ips"),
-		"(Deprecated) Number of bad IPs stored in the database (per jail).",
-		[]string{"jail"}, nil,
-	)
-	deprecatedMetricEnabledJails = prometheus.NewDesc(
-		prometheus.BuildFQName(deprecatedNamespace, "", "enabled_jails"),
-		"(Deprecated) Enabled jails.",
-		[]string{"jail"}, nil,
-	)
-	deprecatedMetricErrorCount = prometheus.NewDesc(
-		prometheus.BuildFQName(deprecatedNamespace, "", "errors"),
-		"(Deprecated) Number of errors found since startup.",
-		[]string{"type"}, nil,
-	)
-
-	metricErrorCount = prometheus.NewDesc(
-		prometheus.BuildFQName(namespace, "", "errors"),
-		"Number of errors found since startup",
-		[]string{"type"}, nil,
-	)
-	metricServerUp = prometheus.NewDesc(
-		prometheus.BuildFQName(namespace, "", "up"),
-		"Check if the fail2ban server is up",
-		nil, nil,
-	)
-	metricJailCount = prometheus.NewDesc(
-		prometheus.BuildFQName(namespace, "", "jail_count"),
-		"Number of defined jails",
-		nil, nil,
-	)
-	metricJailFailedCurrent = prometheus.NewDesc(
-		prometheus.BuildFQName(namespace, "", "jail_failed_current"),
-		"Number of current failures on this jail's filter",
-		[]string{"jail"}, nil,
-	)
-	metricJailFailedTotal = prometheus.NewDesc(
-		prometheus.BuildFQName(namespace, "", "jail_failed_total"),
-		"Number of total failures on this jail's filter",
-		[]string{"jail"}, nil,
-	)
-	metricJailBannedCurrent = prometheus.NewDesc(
-		prometheus.BuildFQName(namespace, "", "jail_banned_current"),
-		"Number of IPs currently banned in this jail",
-		[]string{"jail"}, nil,
-	)
-	metricJailBannedTotal = prometheus.NewDesc(
-		prometheus.BuildFQName(namespace, "", "jail_banned_total"),
-		"Total number of IPs banned by this jail (includes expired bans)",
-		[]string{"jail"}, nil,
-	)
 )
 
-type Exporter struct {
-	db                         *fail2banDb.Fail2BanDB
-	socketPath                 string
-	lastError                  error
-	dbErrorCount               int
-	socketConnectionErrorCount int
-	socketRequestErrorCount    int
-}
-
-func (e *Exporter) Describe(ch chan<- *prometheus.Desc) {
-	if e.db != nil {
-		ch <- deprecatedMetricUp
-		ch <- deprecatedMetricBadIpsPerJail
-		ch <- deprecatedMetricBannedIpsPerJail
-		ch <- deprecatedMetricEnabledJails
-		ch <- deprecatedMetricErrorCount
-	}
-	if e.socketPath != "" {
-		ch <- metricServerUp
-		ch <- metricJailCount
-		ch <- metricJailFailedCurrent
-		ch <- metricJailFailedTotal
-		ch <- metricJailBannedCurrent
-		ch <- metricJailBannedTotal
-	}
-	ch <- metricErrorCount
-}
-
-func (e *Exporter) Collect(ch chan<- prometheus.Metric) {
-	if e.db != nil {
-		e.collectDeprecatedBadIpsPerJailMetrics(ch)
-		e.collectDeprecatedBannedIpsPerJailMetrics(ch)
-		e.collectDeprecatedEnabledJailMetrics(ch)
-		e.collectDeprecatedUpMetric(ch)
-		e.collectDeprecatedErrorCountMetric(ch)
-	}
-	if e.socketPath != "" {
-		s, err := socket.ConnectToSocket(e.socketPath)
-		if err != nil {
-			log.Printf("error opening socket: %v", err)
-			e.socketConnectionErrorCount++
-		} else {
-			defer s.Close()
-		}
-		e.collectServerUpMetric(ch, s)
-		if err == nil && s != nil {
-			e.collectJailMetrics(ch, s)
-		}
-	}
-	e.collectErrorCountMetric(ch)
-}
-
-func (e *Exporter) collectDeprecatedUpMetric(ch chan<- prometheus.Metric) {
-	var upMetricValue float64 = 1
-	if e.lastError != nil {
-		upMetricValue = 0
-	}
-	ch <- prometheus.MustNewConstMetric(
-		deprecatedMetricUp, prometheus.GaugeValue, upMetricValue,
-	)
-}
-
-func (e *Exporter) collectDeprecatedErrorCountMetric(ch chan<- prometheus.Metric) {
-	ch <- prometheus.MustNewConstMetric(
-		deprecatedMetricErrorCount, prometheus.CounterValue, float64(e.dbErrorCount), "db",
-	)
-}
-
-func (e *Exporter) collectDeprecatedBadIpsPerJailMetrics(ch chan<- prometheus.Metric) {
-	jailNameToCountMap, err := e.db.CountBadIpsPerJail()
-	e.lastError = err
-
-	if err != nil {
-		e.dbErrorCount++
-		log.Print(err)
-	}
-
-	for jailName, count := range jailNameToCountMap {
-		ch <- prometheus.MustNewConstMetric(
-			deprecatedMetricBadIpsPerJail, prometheus.GaugeValue, float64(count), jailName,
-		)
-	}
-}
-
-func (e *Exporter) collectDeprecatedBannedIpsPerJailMetrics(ch chan<- prometheus.Metric) {
-	jailNameToCountMap, err := e.db.CountBannedIpsPerJail()
-	e.lastError = err
-
-	if err != nil {
-		e.dbErrorCount++
-		log.Print(err)
-	}
-
-	for jailName, count := range jailNameToCountMap {
-		ch <- prometheus.MustNewConstMetric(
-			deprecatedMetricBannedIpsPerJail, prometheus.GaugeValue, float64(count), jailName,
-		)
-	}
-}
-
-func (e *Exporter) collectDeprecatedEnabledJailMetrics(ch chan<- prometheus.Metric) {
-	jailNameToEnabledMap, err := e.db.JailNameToEnabledValue()
-	e.lastError = err
-
-	if err != nil {
-		e.dbErrorCount++
-		log.Print(err)
-	}
-
-	for jailName, count := range jailNameToEnabledMap {
-		ch <- prometheus.MustNewConstMetric(
-			deprecatedMetricEnabledJails, prometheus.GaugeValue, float64(count), jailName,
-		)
-	}
-}
-
-func (e *Exporter) collectErrorCountMetric(ch chan<- prometheus.Metric) {
-	ch <- prometheus.MustNewConstMetric(
-		metricErrorCount, prometheus.CounterValue, float64(e.dbErrorCount), "db",
-	)
-	ch <- prometheus.MustNewConstMetric(
-		metricErrorCount, prometheus.CounterValue, float64(e.socketConnectionErrorCount), "socket_conn",
-	)
-	ch <- prometheus.MustNewConstMetric(
-		metricErrorCount, 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++
-			log.Print(err)
-		}
-		if err == nil && pingSuccess {
-			serverUp = 1
-		}
-	}
-	ch <- prometheus.MustNewConstMetric(
-		metricServerUp, prometheus.GaugeValue, serverUp,
-	)
-}
-
-func (e *Exporter) collectJailMetrics(ch chan<- prometheus.Metric, s *socket.Fail2BanSocket) {
-	jails, err := s.GetJails()
-	var count float64 = 0
-	if err != nil {
-		e.socketRequestErrorCount++
-		log.Print(err)
-	}
-	if err == nil {
-		count = float64(len(jails))
-	}
-	ch <- prometheus.MustNewConstMetric(
-		metricJailCount, prometheus.GaugeValue, count,
-	)
-
-	for i := range jails {
-		e.collectJailStatsMetric(ch, s, jails[i])
-	}
-}
-
-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
-	}
-
-	ch <- prometheus.MustNewConstMetric(
-		metricJailFailedCurrent, prometheus.GaugeValue, float64(stats.FailedCurrent), jail,
-	)
-	ch <- prometheus.MustNewConstMetric(
-		metricJailFailedTotal, prometheus.GaugeValue, float64(stats.FailedTotal), jail,
-	)
-	ch <- prometheus.MustNewConstMetric(
-		metricJailBannedCurrent, prometheus.GaugeValue, float64(stats.BannedCurrent), jail,
-	)
-	ch <- prometheus.MustNewConstMetric(
-		metricJailBannedTotal, prometheus.GaugeValue, float64(stats.BannedTotal), jail,
-	)
-}
-
 func printAppVersion() {
 	fmt.Println(version)
 	fmt.Printf("    build date:  %s\r\n    commit hash: %s\r\n    built by:    %s\r\n", date, commit, builtBy)
 }
 
+func rootHtmlHandler(w http.ResponseWriter, r *http.Request) {
+	_, err := w.Write([]byte(
+		`<html>
+			<head><title>Fail2Ban Exporter</title></head>
+			<body>
+			<h1>Fail2Ban Exporter</h1>
+			<p><a href="` + metricsPath + `">Metrics</a></p>
+			</body>
+		</html>`))
+	if err != nil {
+		log.Printf("error handling root url: %v", err)
+		w.WriteHeader(http.StatusInternalServerError)
+	}
+}
+
 func main() {
 	appSettings := cfg.Parse()
 	if appSettings.VersionMode {
 		printAppVersion()
 	} else {
-		log.Print("starting fail2ban exporter")
+		addr := fmt.Sprintf("0.0.0.0:%d", appSettings.MetricsPort)
 
-		exporter := &Exporter{}
-		if appSettings.Fail2BanDbPath != "" {
-			log.Print("database-based metrics have been deprecated and will be removed in a future release")
-			exporter.db = fail2banDb.MustConnectToDb(appSettings.Fail2BanDbPath)
-		}
-		if appSettings.Fail2BanSocketPath != "" {
-			exporter.socketPath = appSettings.Fail2BanSocketPath
-		}
+		log.Printf("starting fail2ban exporter at %s", addr)
+
+		exporter := export.NewExporter(appSettings, version)
 		prometheus.MustRegister(exporter)
 
-		http.Handle("/metrics", promhttp.Handler())
-		log.Fatal(http.ListenAndServe(fmt.Sprintf(":%d", appSettings.MetricsPort), nil))
+		http.HandleFunc("/", rootHtmlHandler)
+		http.Handle(metricsPath, promhttp.Handler())
+		log.Printf("metrics available at '%s'", metricsPath)
+
+		svrErr := make(chan error)
+		go func() {
+			svrErr <- http.ListenAndServe(addr, nil)
+		}()
+		log.Print("ready")
+
+		err := <-svrErr
+		log.Print(err)
 	}
 }

src/socket/fail2banSocket.go

@@ -118,6 +118,20 @@ func (s *Fail2BanSocket) GetJailStats(jail string) (JailStats, error) {
 	return stats, newBadFormatError(statusCommand, response)
 }
 
+func (s *Fail2BanSocket) GetServerVersion() (string, error) {
+	response, err := s.sendCommand([]string{versionCommand})
+	if err != nil {
+		return "", err
+	}
+
+	if lvl1, ok := response.(*types.Tuple); ok {
+		if versionStr, ok := lvl1.Get(1).(string); ok {
+			return versionStr, nil
+		}
+	}
+	return "", newBadFormatError(versionCommand, response)
+}
+
 func newBadFormatError(command string, data interface{}) error {
 	return fmt.Errorf("(%s) unexpected response format - cannot parse: %v", command, data)
 }

src/socket/protocol.go

@@ -11,6 +11,7 @@ const (
 	commandTerminator    = "<F2B_END_COMMAND>"
 	pingCommand          = "ping"
 	statusCommand        = "status"
+	versionCommand       = "version"
 	socketReadBufferSize = 1024
 )