Add config file support

README.md

@@ -120,6 +120,32 @@ Environment variables can be used to set parameters without using command line f
 | `F2BD_SOCKET`              | `-s, --socket`          | Fail2ban socket path                        | `/var/run/fail2ban/fail2ban.sock` |
 | `F2BD_TRUST_PROXY_HEADERS` | `--trust-proxy-headers` | Trust proxy headers like X-Forwarded-For    | `false`                           |
 
+### Config file
+
+It is also possible to configure the application using a config file.
+Supported config file formats are the ones supported by the [viper](https://github.com/spf13/viper) library.
+
+The config file can be located at `/etc/fail2ban-dashboard/`, the user home directory `~/.config/fail2ban-dashboard/` or the current working directory.
+
+For example, for a TOML file located at `/etc/fail2ban-dashboard/config.toml` the chaning the address is like
+
+```toml
+address="127.0.0.1:4000"
+```
+
+Supported configurations are
+
+| Configuration   |
+|-----------------|
+| socket          |
+| address         |
+| auth-user       |
+| auth-password   |
+| cache-dir       |
+| log-level       |
+| base-path       |
+| metrics-address |
+
 ## Dashboard
 
 ### Web application

cmd/fail2ban-dashboard/fail2ban-dashboard.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"errors"
 	"fmt"
 	"os"
 	"strings"
@@ -36,6 +37,19 @@ var versionCmd = &cobra.Command{
 }
 
 func setupRootCommand() {
+	// Add search paths to find the file
+	viper.SetConfigName("config")
+	viper.AddConfigPath("/etc/fail2ban-dashboard/")
+	viper.AddConfigPath("$HOME/.config/fail2ban-dashboard")
+	viper.AddConfigPath(".")
+
+	if err := viper.ReadInConfig(); err != nil {
+		if _, ok := errors.AsType[viper.ConfigFileNotFoundError](err); !ok {
+			fmt.Printf("Could not parse config file: %s\n", err)
+			os.Exit(1)
+		}
+	}
+
 	viper.AutomaticEnv()
 	viper.SetEnvPrefix("F2BD")
 	viper.SetEnvKeyReplacer(strings.NewReplacer("-", "_"))

server/server.go

@@ -4,6 +4,7 @@ import (
 	"crypto/rand"
 	_ "embed"
 	"encoding/binary"
+	"encoding/hex"
 	"fmt"
 	"html/template"
 	"net"
@@ -103,6 +104,14 @@ type detailData struct {
 	Jail         store.Jail
 }
 
+func generateRandomPassword() string {
+	b := make([]byte, 16)
+	if _, err := rand.Read(b); err != nil {
+		return "default-password-change-me"
+	}
+	return hex.EncodeToString(b)
+}
+
 func RegisterDashboardEndpoints(app *fiber.App, dataStore *store.DataStore, geoIP *geoip.GeoIP, configuration *Configuration) error {
 
 	templateFunctions := template.FuncMap{
@@ -197,13 +206,13 @@ func RegisterDashboardEndpoints(app *fiber.App, dataStore *store.DataStore, geoI
 		}
 		log.Infof("Basic authentication username set to %s", configuration.AuthUser)
 		if configuration.AuthPassword == "" {
-			configuration.AuthPassword = rand.Text()
+			configuration.AuthPassword = generateRandomPassword()
 			log.Infof("Basic authentication password set to %s", configuration.AuthPassword)
 		}
 
 		app.Use(basicauth.New(basicauth.Config{
-			Users: map[string]string{
-				configuration.AuthUser: configuration.AuthPassword,
+			Authorizer: func(user, password string, c fiber.Ctx) bool {
+				return user == configuration.AuthUser && password == configuration.AuthPassword
 			},
 		}))
 	}