Add Prometheus metrics

.github/workflows/build.yml

@@ -46,7 +46,7 @@ jobs:
       - name: golangci-lint
         uses: golangci/golangci-lint-action@v8
         with:
-          version: v2.4.0
+          version: v2.9.0
 
       - name: Test
         run: |

.github/workflows/release.yml

@@ -46,7 +46,7 @@ jobs:
       - name: golangci-lint
         uses: golangci/golangci-lint-action@v8
         with:
-          version: v2.4.0
+          version: v2.9.0
 
       - name: Upload build result
         uses: actions/upload-artifact@v4

README.md

@@ -1,3 +1,11 @@
+<p align="center">
+    <picture>
+      <source media="(prefers-color-scheme: dark)" srcset="docs/content/assets/fail2ban-dashboard-mascot_250.png">
+      <source media="(prefers-color-scheme: light)" srcset="docs/content/assets/fail2ban-dashboard-mascot_250.png">
+      <img alt="fail2ban dashboard mascot" title="fail2ban dashboard mascot" src="docs/content/assets/fail2ban-dashboard-mascot_250.png">
+    </picture>
+</p>
+
 # fail2ban-dashboard
 
 ![build](https://github.com/webishdev/fail2ban-dashboard/actions/workflows/build.yml/badge.svg)
@@ -49,10 +57,12 @@ Flags:
   -c, --cache-dir string           directory to cache GeoIP data, also F2BD_CACHE_DIR (default current working directory)
   -h, --help                       help for fail2ban-dashboard
       --log-level string           log level (trace, debug, info, warn, error), also F2BD_LOG_LEVEL (default "info")
+  -m, --metrics                    will provide metrics endpoint, also F2BD_METRICS
+      --metrics-address string     address to make metrics available, also F2BD_METRICS_ADDRESS (default "127.0.0.1:9100")
       --refresh-seconds int        fail2ban data refresh in seconds (value from 10 to 600), also F2BD_REFRESH_SECONDS (default 30)
       --scheduled-geoip-download   will keep GeoIP cache update even without accessing the dashboard, also F2BD_SCHEDULED_GEOIP_DOWNLOAD (default true)
       --skip-version-check         skip fail2ban version check (use at your own risk), also F2BD_SKIP_VERSION_CHECK
-  -s, --socket string              fail2ban socket, also F2BD_SOCKET (default "/var/run/fail2ban/fail2ban.sock")
+  -s, --socket string              location of the fail2ban socket, also F2BD_SOCKET (default "/var/run/fail2ban/fail2ban.sock")
       --trust-proxy-headers        trust proxy headers like X-Forwarded-For, also F2BD_TRUST_PROXY_HEADERS
 
 Use "fail2ban-dashboard [command] --help" for more information about a command.
@@ -68,12 +78,43 @@ The `root` user is necessary as by default the `fail2ban` socket is only accessi
 
 ## Dashboard
 
-When started, check http://localhost:3000/
+When started, check http://127.0.0.1:3000/
 
 Basic authentication can be enabled with the `--auth-user` and/or `--auth-password` flags.  
 When only `--auth-user` is provided, the password will be generated and show in the logs/console.  
 When only `--auth-password` is provided, the user will be named `admin`.
 
+### Metrics
+
+When metrics are enabled with `-m` the metrics endpoint is available at http://127.0.0.1:9100/metrics and the address can be changed with `--metrics-address`.
+
+The following example shows which metrics are provided
+
+```text
+# HELP f2b_jail_banned_current Amount of banned IPs currently in jail
+# TYPE f2b_jail_banned_current gauge
+f2b_jail_banned_current{jail="postfix"} 13
+f2b_jail_banned_current{jail="sshd"} 33
+# HELP f2b_jail_banned_total Amount of banned IPs total in jail
+# TYPE f2b_jail_banned_total gauge
+f2b_jail_banned_total{jail="postfix"} 13
+f2b_jail_banned_total{jail="sshd"} 33
+# HELP f2b_jail_count The number of jails in fail2ban
+# TYPE f2b_jail_count gauge
+f2b_jail_count 2
+# HELP f2b_jail_failed_current Amount of failed IPs currently in jail
+# TYPE f2b_jail_failed_current gauge
+f2b_jail_failed_current{jail="postfix"} 0
+f2b_jail_failed_current{jail="sshd"} 0
+# HELP f2b_jail_failed_total Amount of failed IPs total in jail
+# TYPE f2b_jail_failed_total gauge
+f2b_jail_failed_total{jail="postfix"} 0
+f2b_jail_failed_total{jail="sshd"} 0
+# HELP fail2ban_dashboard_info The fail2ban Dashboard build information
+# TYPE fail2ban_dashboard_info gauge
+fail2ban_dashboard_info{fail2ban_version="1.1.0",version="development"} 1
+```
+
 ### Environment variables
 
 Environment variables can be used to set parameters without using command line flags.

cmd/fail2ban-dashboard/fail2ban-dashboard.go

@@ -11,6 +11,7 @@ import (
 	"github.com/spf13/viper"
 	client "github.com/webishdev/fail2ban-dashboard/fail2ban-client"
 	"github.com/webishdev/fail2ban-dashboard/geoip"
+	"github.com/webishdev/fail2ban-dashboard/metrics"
 	"github.com/webishdev/fail2ban-dashboard/server"
 	"github.com/webishdev/fail2ban-dashboard/store"
 )
@@ -71,7 +72,7 @@ func init() {
 		os.Exit(1)
 	}
 
-	flags.StringP("socket", "s", "/var/run/fail2ban/fail2ban.sock", "fail2ban socket, also F2BD_SOCKET")
+	flags.StringP("socket", "s", "/var/run/fail2ban/fail2ban.sock", "location of the fail2ban socket, also F2BD_SOCKET")
 	socketError := viper.BindPFlag("socket", flags.Lookup("socket"))
 	if socketError != nil {
 		fmt.Printf("Could not bind socket flag: %s\n", socketError)
@@ -120,6 +121,20 @@ func init() {
 		os.Exit(1)
 	}
 
+	flags.BoolP("metrics", "m", false, "will provide metrics endpoint, also F2BD_METRICS")
+	metricsErr := viper.BindPFlag("metrics", flags.Lookup("metrics"))
+	if metricsErr != nil {
+		fmt.Printf("Could not bind metrics flag: %s\n", logLevelErr)
+		os.Exit(1)
+	}
+
+	flags.String("metrics-address", "127.0.0.1:9100", "address to make metrics available, also F2BD_METRICS_ADDRESS")
+	metricsAddressErr := viper.BindPFlag("metrics-address", flags.Lookup("metrics-address"))
+	if metricsAddressErr != nil {
+		fmt.Printf("Could not bind metrics-address flag: %s\n", logLevelErr)
+		os.Exit(1)
+	}
+
 	rootCmd.AddCommand(versionCmd)
 }
 
@@ -144,6 +159,8 @@ func run(_ *cobra.Command, _ []string) {
 	refreshSeconds := viper.GetInt("refresh-seconds")
 	basePath := viper.GetString("base-path")
 	enableSchedule := viper.GetBool("scheduled-geoip-download")
+	metricsEnabled := viper.GetBool("metrics")
+	metricsAddress := viper.GetString("metrics-address")
 
 	// Set log level
 	switch logLevel {
@@ -240,12 +257,28 @@ func run(_ *cobra.Command, _ []string) {
 	geoIP := geoip.NewGeoIP(absolutCacheDir, enableSchedule)
 
 	configuration := &server.Configuration{
-		Address:      address,
-		AuthUser:     user,
-		AuthPassword: password,
+		Address:           address,
+		AuthUser:          user,
+		AuthPassword:      password,
+		BasePath:          basePath,
+		TrustProxyHeaders: trustProxyHeaders,
+		Fail2BanVersion:   fail2banVersion,
+		Version:           Version,
+	}
+
+	if metricsEnabled {
+		metricConfiguration := &metrics.Configuration{
+			Address:         metricsAddress,
+			Fail2BanVersion: fail2banVersion,
+			Version:         Version,
+		}
+		metrics.ServeMetrics(dataStore, metricConfiguration)
+
+	} else {
+		log.Info("Metrics disabled")
 	}
 
-	serveError := server.Serve(Version, fail2banVersion, basePath, trustProxyHeaders, dataStore, geoIP, configuration)
+	serveError := server.Serve(dataStore, geoIP, configuration)
 	if serveError != nil {
 		log.Errorf("Could not start server: %s\n", serveError)
 		os.Exit(1)