Merge branch '4-configure-tool-using-cli-parameters' into 'main'

Resolve "Configure tool using CLI parameters"

Closes #4

See merge request hectorjsmith/fail2ban-prometheus-exporter!3

cfg/cfg.go

@@ -0,0 +1,48 @@
+package cfg
+
+import (
+	"flag"
+	"fmt"
+	"os"
+)
+
+const (
+	minServerPort = 1000
+	maxServerPort = 65535
+)
+
+type AppSettings struct {
+	VersionMode    bool
+	MetricsPort    int
+	Fail2BanDbPath string
+}
+
+func Parse() *AppSettings {
+	appSettings := &AppSettings{}
+	flag.BoolVar(&appSettings.VersionMode, "version", false, "show version info and exit")
+	flag.IntVar(&appSettings.MetricsPort, "port", 9191, "port to use for the metrics server")
+	flag.StringVar(&appSettings.Fail2BanDbPath, "db", "", "path to the fail2ban sqlite database")
+
+	flag.Parse()
+	appSettings.validateFlags()
+	return appSettings
+}
+
+func (settings *AppSettings) validateFlags() {
+	var flagsValid = true
+	if !settings.VersionMode {
+		if settings.Fail2BanDbPath == "" {
+			fmt.Println("missing flag 'db'")
+			flagsValid = false
+		}
+		if settings.MetricsPort < minServerPort || settings.MetricsPort > maxServerPort {
+			fmt.Printf("invalid server port, must be within %d and %d (found %d)\n",
+				minServerPort, maxServerPort, settings.MetricsPort)
+			flagsValid = false
+		}
+	}
+	if !flagsValid {
+		flag.Usage()
+		os.Exit(1)
+	}
+}

exporter.go

@@ -1,7 +1,9 @@
 package main
 
 import (
+	"fail2ban-prometheus-exporter/cfg"
 	fail2banDb "fail2ban-prometheus-exporter/db"
+	"fmt"
 	_ "github.com/mattn/go-sqlite3"
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/client_golang/prometheus/promhttp"
@@ -12,7 +14,11 @@ import (
 const namespace = "fail2ban"
 
 var (
-	db       = fail2banDb.MustConnectToDb("fail2ban.sqlite3")
+	version = "dev"
+	commit  = "none"
+	date    = "unknown"
+	builtBy = "unknown"
+
 	metricUp = prometheus.NewDesc(
 		prometheus.BuildFQName(namespace, "", "up"),
 		"Was the last fail2ban query successful.",
@@ -31,6 +37,7 @@ var (
 )
 
 type Exporter struct {
+	db *fail2banDb.Fail2BanDB
 }
 
 func (e *Exporter) Describe(ch chan<- *prometheus.Desc) {
@@ -43,12 +50,12 @@ func (e *Exporter) Collect(ch chan<- prometheus.Metric) {
 	ch <- prometheus.MustNewConstMetric(
 		metricUp, prometheus.GaugeValue, 1,
 	)
-	collectBadIpsPerJailMetrics(ch)
-	collectBannedIpsPerJailMetrics(ch)
+	e.collectBadIpsPerJailMetrics(ch)
+	e.collectBannedIpsPerJailMetrics(ch)
 }
 
-func collectBadIpsPerJailMetrics(ch chan<- prometheus.Metric) {
-	jailNameToCountMap, err := db.CountBadIpsPerJail()
+func (e *Exporter) collectBadIpsPerJailMetrics(ch chan<- prometheus.Metric) {
+	jailNameToCountMap, err := e.db.CountBadIpsPerJail()
 	if err != nil {
 		log.Print(err)
 	}
@@ -60,8 +67,8 @@ func collectBadIpsPerJailMetrics(ch chan<- prometheus.Metric) {
 	}
 }
 
-func collectBannedIpsPerJailMetrics(ch chan<- prometheus.Metric) {
-	jailNameToCountMap, err := db.CountBannedIpsPerJail()
+func (e *Exporter) collectBannedIpsPerJailMetrics(ch chan<- prometheus.Metric) {
+	jailNameToCountMap, err := e.db.CountBannedIpsPerJail()
 	if err != nil {
 		log.Print(err)
 	}
@@ -73,12 +80,24 @@ func collectBannedIpsPerJailMetrics(ch chan<- prometheus.Metric) {
 	}
 }
 
+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 main() {
+	appSettings := cfg.Parse()
+	if appSettings.VersionMode {
+		printAppVersion()
+	} else {
 		log.Print("starting fail2ban exporter")
 
-	exporter := &Exporter{}
+		exporter := &Exporter{
+			db: fail2banDb.MustConnectToDb(appSettings.Fail2BanDbPath),
+		}
 		prometheus.MustRegister(exporter)
 
 		http.Handle("/metrics", promhttp.Handler())
-	log.Fatal(http.ListenAndServe(":9101", nil))
+		log.Fatal(http.ListenAndServe(fmt.Sprintf(":%d", appSettings.MetricsPort), nil))
+	}
 }