feat: rewrite cli flags and environment variables

Replace existing CLI flags to make them more consistent and follow a more
standard format.
Remove CLI flags and environment variables that are no longer relevant.
Add short `-v` option for version flag.
Update README with new documentation.

BREAKING CHANGE: Replace `--socket` flag with `--collector.f2b.socket`.
BREAKING CHANGE: Merge `--port` flag and `--web.listen-address` into a single flag.
BREAKING CHANGE: Remove `--collector.textfile` flag, its value is now derived from `--collector.textfile.directory`.
BREAKING CHANGE: Remove `F2B_COLLECTOR_TEXT` and `F2B_WEB_PORT` environment variables.

README.md

@@ -13,7 +13,7 @@ This exporter collects metrics from a running fail2ban instance.
 
 Once the exporter is running, metrics are available at `localhost:9191/metrics`.
 
-(The default port is `9191` but can be modified with the `--port` flag)
+(The default port is `9191` but can be modified with the `--web.listen-address` flag)
 
 The exporter communicates with the fail2ban server over its socket.
 This allows the data collected by the exporter to always align with the output of the `fail2ban-client`.
@@ -38,22 +38,21 @@ See the [releases page](https://gitlab.com/hectorjsmith/fail2ban-prometheus-expo
 **CLI Usage**
 ```
 $ fail2ban-prometheus-exporter -h
-usage: exporter [<flags>]
+usage: fail2ban-prometheus-exporter [<flags>]
 
 Flags:
-  -h, --help                Show context-sensitive help (also try --help-long and --help-man).
+  -h, --help     Show context-sensitive help (also try --help-long and --help-man).
-      --version             show version info and exit
+  -v, --version  show version info and exit
-      --port=9191           port to use for the metrics server
+      --collector.f2b.socket="/var/run/fail2ban/fail2ban.sock"  
-      --web.listen-address="0.0.0.0"
+                 path to the fail2ban server socket
-                            address to use for the metrics server
+      --collector.textfile.directory=""  
-      --socket=""           path to the fail2ban server socket
+                 directory to read text files with metrics from
-      --collector.textfile  enable the textfile collector
+      --web.listen-address=":9191"  
-      --collector.textfile.directory=""
+                 address to use for the metrics server
-                            directory to read text files with metrics from
+      --web.basic-auth.username=""  
-      --web.basic-auth.username=""
+                 username to use to protect endpoints with basic auth
-                            username to use to protect endpoints with basic auth
+      --web.basic-auth.password=""  
-      --web.basic-auth.password=""
+                 password to use to protect endpoints with basic auth
-                            password to use to protect endpoints with basic auth
 ```
 
 **Environment variables**
@@ -62,9 +61,7 @@ The tool can also be configured using environment variables. Each CLI parameter
 
 ```
 F2B_COLLECTOR_SOCKET
-F2B_COLLECTOR_TEXT
 F2B_COLLECTOR_TEXT_PATH
-F2B_WEB_PORT
 F2B_WEB_LISTEN_ADDRESS
 F2B_WEB_BASICAUTH_USER
 F2B_WEB_BASICAUTH_PASS
@@ -73,7 +70,7 @@ F2B_WEB_BASICAUTH_PASS
 **Example**
 
 ```
-fail2ban-prometheus-exporter --socket /var/run/fail2ban/fail2ban.sock --port 9191
+fail2ban-prometheus-exporter --collector.f2b.socket=/var/run/fail2ban/fail2ban.sock --web.listen-address=":9191"
 ```
 
 Note that the exporter will need read access to the fail2ban socket.
@@ -232,9 +229,7 @@ Status for the jail: sshd|- Filter
 
 For more flexibility the exporter also allows exporting metrics collected from a text file.
 
-To enable textfile metrics:
+To enable textfile metrics provide the directory to read files from with the `--collector.textfile.directory` flag.
-1. Enable the collector with `--collector.textfile=true`
-2. Provide the directory to read files from with the `--collector.textfile.directory` flag
 
 Metrics collected from these files will be exposed directly alongside the other metrics without any additional processing.
 This means that it is the responsibility of the file creator to ensure the format is correct.
@@ -252,8 +247,8 @@ textfile_error{path="file.prom"} 0
 **Running in Docker**
 
 To collect textfile metrics inside a docker container, a couple of things need to be done:
-1. Mount the folder with the metrics
+1. Mount the folder with the metrics files
-2. Set the relevant environment variables
+2. Set the `F2B_COLLECTOR_TEXT_PATH` environment variable
 
 *For example:*
 ```
@@ -261,7 +256,6 @@ docker run -d \
     --name "fail2ban-exporter" \
     -v /var/run/fail2ban:/var/run/fail2ban:ro \
     -v /path/to/metrics:/app/metrics/:ro \
-    -e F2B_COLLECTOR_TEXT=true \
     -e F2B_COLLECTOR_TEXT_PATH=/app/metrics \
     -p "9191:9191" \
     registry.gitlab.com/hectorjsmith/fail2ban-prometheus-exporter:latest

src/cfg/cfg.go

@@ -7,25 +7,19 @@ import (
 )
 
 const (
-	minServerPort               = 1000
+	socketEnvName            = "F2B_COLLECTOR_SOCKET"
-	maxServerPort               = 65535
+	fileCollectorPathEnvName = "F2B_COLLECTOR_TEXT_PATH"
-	socketEnvName               = "F2B_COLLECTOR_SOCKET"
+	addressEnvName           = "F2B_WEB_LISTEN_ADDRESS"
-	fileCollectorEnabledEnvName = "F2B_COLLECTOR_TEXT"
+	basicAuthUserEnvName     = "F2B_WEB_BASICAUTH_USER"
-	fileCollectorPathEnvName    = "F2B_COLLECTOR_TEXT_PATH"
+	basicAuthPassEnvName     = "F2B_WEB_BASICAUTH_PASS"
-	portEnvName                 = "F2B_WEB_PORT"
-	addressEnvName              = "F2B_WEB_LISTEN_ADDRESS"
-	basicAuthUserEnvName        = "F2B_WEB_BASICAUTH_USER"
-	basicAuthPassEnvName        = "F2B_WEB_BASICAUTH_PASS"
 )
 
 type AppSettings struct {
-	VersionMode          bool
+	VersionMode        bool
-	MetricsAddress       string
+	MetricsAddress     string
-	MetricsPort          int
+	Fail2BanSocketPath string
-	Fail2BanSocketPath   string
+	FileCollectorPath  string
-	FileCollectorPath    string
+	BasicAuthProvider  *hashedBasicAuth
-	FileCollectorEnabled bool
-	BasicAuthProvider    *hashedBasicAuth
 }
 
 func init() {
@@ -42,31 +36,22 @@ func Parse() *AppSettings {
 func readParamsFromCli(settings *AppSettings) {
 	versionMode := kingpin.
 		Flag("version", "show version info and exit").
+		Short('v').
 		Default("false").
 		Bool()
 	socketPath := kingpin.
-		Flag("socket", "path to the fail2ban server socket").
+		Flag("collector.f2b.socket", "path to the fail2ban server socket").
 		Default("/var/run/fail2ban/fail2ban.sock").
 		Envar(socketEnvName).
 		String()
-	fileCollectorEnabled := kingpin.
-		Flag("collector.textfile", "enable the textfile collector").
-		Default("false").
-		Envar(fileCollectorEnabledEnvName).
-		Bool()
 	fileCollectorPath := kingpin.
 		Flag("collector.textfile.directory", "directory to read text files with metrics from").
 		Default("").
 		Envar(fileCollectorPathEnvName).
 		String()
-	port := kingpin.
-		Flag("port", "port to use for the metrics server").
-		Default("9191").
-		Envar(portEnvName).
-		Int()
 	address := kingpin.
 		Flag("web.listen-address", "address to use for the metrics server").
-		Default("0.0.0.0").
+		Default(":9191").
 		Envar(addressEnvName).
 		String()
 	rawBasicAuthUsername := kingpin.
@@ -83,10 +68,8 @@ func readParamsFromCli(settings *AppSettings) {
 	kingpin.Parse()
 
 	settings.VersionMode = *versionMode
-	settings.MetricsPort = *port
 	settings.MetricsAddress = *address
 	settings.Fail2BanSocketPath = *socketPath
-	settings.FileCollectorEnabled = *fileCollectorEnabled
 	settings.FileCollectorPath = *fileCollectorPath
 	settings.setBasicAuthValues(*rawBasicAuthUsername, *rawBasicAuthPassword)
 }
@@ -102,13 +85,8 @@ func (settings *AppSettings) validateFlags() {
 			fmt.Println("error: fail2ban socket path must not be blank")
 			flagsValid = false
 		}
-		if settings.MetricsPort < minServerPort || settings.MetricsPort > maxServerPort {
+		if settings.MetricsAddress == "" {
-			fmt.Printf("error: invalid server port, must be within %d and %d (found %d)\n",
+			fmt.Println("error: invalid server address, must not be blank")
-				minServerPort, maxServerPort, settings.MetricsPort)
-			flagsValid = false
-		}
-		if settings.FileCollectorEnabled && settings.FileCollectorPath == "" {
-			fmt.Println("error: file collector directory path must not be empty if collector enabled")
 			flagsValid = false
 		}
 		if (len(settings.BasicAuthProvider.username) > 0) != (len(settings.BasicAuthProvider.password) > 0) {

src/collector/textfile/collector.go

@@ -20,7 +20,7 @@ type fileData struct {
 
 func NewCollector(appSettings *cfg.AppSettings) *Collector {
 	collector := &Collector{
-		enabled:    appSettings.FileCollectorEnabled,
+		enabled:    appSettings.FileCollectorPath != "",
 		folderPath: appSettings.FileCollectorPath,
 		fileMap:    make(map[string]*fileData),
 	}

src/exporter.go

@@ -54,9 +54,8 @@ func main() {
 	if appSettings.VersionMode {
 		printAppVersion()
 	} else {
-		addr := fmt.Sprintf("%s:%d", appSettings.MetricsAddress, appSettings.MetricsPort)
 		log.Printf("fail2ban exporter version %s", version)
-		log.Printf("starting server at %s", addr)
+		log.Printf("starting server at %s", appSettings.MetricsAddress)
 
 		f2bCollector := f2b.NewExporter(appSettings, version)
 		prometheus.MustRegister(f2bCollector)
@@ -78,7 +77,7 @@ func main() {
 
 		svrErr := make(chan error)
 		go func() {
-			svrErr <- http.ListenAndServe(addr, nil)
+			svrErr <- http.ListenAndServe(appSettings.MetricsAddress, nil)
 		}()
 		log.Print("ready")