Initial Commit

cfg/cfg.go

@@ -0,0 +1,84 @@
+package cfg
+
+import (
+	"fmt"
+	"log"
+	"os"
+
+	"git.cryptic.systems/volker.raschek/prometheus-fail2ban-exporter/auth"
+	"github.com/alecthomas/kong"
+)
+
+var cliStruct struct {
+	VersionMode          bool   `name:"version" short:"v" help:"Show version info and exit"`
+	DryRunMode           bool   `name:"dry-run" help:"Attempt to connect to the fail2ban socket then exit before starting the server"`
+	ServerAddress        string `name:"web.listen-address" env:"F2B_WEB_LISTEN_ADDRESS" help:"Address to use for the metrics server" default:"${default_address}"`
+	F2bSocketPath        string `name:"collector.f2b.socket" env:"F2B_COLLECTOR_SOCKET" help:"Path to the fail2ban server socket" default:"${default_socket}"`
+	ExitOnSocketError    bool   `name:"collector.f2b.exit-on-socket-connection-error" env:"F2B_EXIT_ON_SOCKET_CONN_ERROR" help:"When set to true the exporter will immediately exit on a fail2ban socket connection error"`
+	TextFileExporterPath string `name:"collector.textfile.directory" env:"F2B_COLLECTOR_TEXT_PATH" help:"Directory to read text files with metrics from"`
+	BasicAuthUser        string `name:"web.basic-auth.username" env:"F2B_WEB_BASICAUTH_USER" help:"Username to use to protect endpoints with basic auth"`
+	BasicAuthPass        string `name:"web.basic-auth.password" env:"F2B_WEB_BASICAUTH_PASS" help:"Password to use to protect endpoints with basic auth"`
+}
+
+func Parse() *AppSettings {
+	ctx := kong.Parse(
+		&cliStruct,
+		kong.Vars{
+			"default_socket":  "/var/run/fail2ban/fail2ban.sock",
+			"default_address": ":9191",
+		},
+		kong.Name("fail2ban_exporter"),
+		kong.Description("🚀 Export prometheus metrics from a running Fail2Ban instance"),
+		kong.UsageOnError(),
+	)
+
+	validateFlags(ctx)
+	settings := &AppSettings{
+		VersionMode:           cliStruct.VersionMode,
+		DryRunMode:            cliStruct.DryRunMode,
+		MetricsAddress:        cliStruct.ServerAddress,
+		Fail2BanSocketPath:    cliStruct.F2bSocketPath,
+		FileCollectorPath:     cliStruct.TextFileExporterPath,
+		ExitOnSocketConnError: cliStruct.ExitOnSocketError,
+		AuthProvider:          createAuthProvider(),
+	}
+	return settings
+}
+
+func createAuthProvider() auth.AuthProvider {
+	username := cliStruct.BasicAuthUser
+	password := cliStruct.BasicAuthPass
+
+	if len(username) == 0 && len(password) == 0 {
+		return auth.NewEmptyAuthProvider()
+	}
+	log.Print("basic auth enabled")
+	return auth.NewBasicAuthProvider(username, password)
+}
+
+func validateFlags(cliCtx *kong.Context) {
+	var flagsValid = true
+	var messages = []string{}
+	if !cliStruct.VersionMode {
+		if cliStruct.F2bSocketPath == "" {
+			messages = append(messages, "error: fail2ban socket path must not be blank")
+			flagsValid = false
+		}
+		if cliStruct.ServerAddress == "" {
+			messages = append(messages, "error: invalid server address, must not be blank")
+			flagsValid = false
+		}
+		if (len(cliStruct.BasicAuthUser) > 0) != (len(cliStruct.BasicAuthPass) > 0) {
+			messages = append(messages, "error: to enable basic auth both the username and the password must be provided")
+			flagsValid = false
+		}
+	}
+	if !flagsValid {
+		cliCtx.PrintUsage(false)
+		fmt.Println()
+		for i := 0; i < len(messages); i++ {
+			fmt.Println(messages[i])
+		}
+		os.Exit(1)
+	}
+}