Add support for configurable binding address

.env.example

@@ -1,5 +1,7 @@
 OWNER_NPUB="npub1utx00neqgqln72j22kej3ux7803c2k986henvvha4thuwfkper4s7r50e8"
 RELAY_URL="relay.utxo.one"
+RELAY_PORT=3355
+RELAY_BIND_ADDRESS="0.0.0.0" # Can be set to a specific IP4 or IP6 address ("" for all interfaces)
 DB_ENGINE="badger" # badger, lmdb (lmdb works best with an nvme, otherwise you might have stability issues)
 
 ## Private Relay Settings

config.go

@@ -14,6 +14,8 @@ type Config struct {
 	OwnerNpub                        string   `json:"owner_npub"`
 	DBEngine                         string   `json:"db_engine"`
 	RelayURL                         string   `json:"relay_url"`
+	RelayPort                        int      `json:"relay_port"`
+	RelayBindAddress                 string   `json:"relay_bind_address"`
 	RelaySoftware                    string   `json:"relay_software"`
 	RelayVersion                     string   `json:"relay_version"`
 	PrivateRelayName                 string   `json:"private_relay_name"`
@@ -52,15 +54,14 @@ type AwsConfig struct {
 }
 
 func loadConfig() Config {
-	godotenv.Load(".env")
-	if os.Getenv("DB_ENGINE") == "" {
-		os.Setenv("DB_ENGINE", "lmdb")
-	}
+	_ = godotenv.Load(".env")
 
 	return Config{
 		OwnerNpub:                        getEnv("OWNER_NPUB"),
-		DBEngine:                         getEnv("DB_ENGINE"),
+		DBEngine:                         getEnvString("DB_ENGINE", "lmdb"),
 		RelayURL:                         getEnv("RELAY_URL"),
+		RelayPort:                        getEnvInt("RELAY_PORT", 3355),
+		RelayBindAddress:                 getEnvString("RELAY_BIND_ADDRESS", "0.0.0.0"),
 		RelaySoftware:                    "https://github.com/bitvora/haven",
 		RelayVersion:                     "v0.4.4",
 		PrivateRelayName:                 getEnv("PRIVATE_RELAY_NAME"),
@@ -121,6 +122,13 @@ func getEnv(key string) string {
 	return value
 }
 
+func getEnvString(key string, defaultValue string) string {
+	if value, ok := os.LookupEnv(key); ok {
+		return value
+	}
+	return defaultValue
+}
+
 func getEnvInt(key string, defaultValue int) int {
 	if value, ok := os.LookupEnv(key); ok {
 		intValue, err := strconv.Atoi(value)

main.go

@@ -48,8 +48,10 @@ func main() {
 
 	http.HandleFunc("/", dynamicRelayHandler)
 
-	log.Printf("🔗 listening at http://localhost:3355")
-	http.ListenAndServe("0.0.0.0:3355", nil)
+	addr := fmt.Sprintf("%s:%d", config.RelayBindAddress, config.RelayPort)
+
+	log.Printf("🔗 listening at %s", addr)
+	http.ListenAndServe(addr, nil)
 }
 
 func dynamicRelayHandler(w http.ResponseWriter, r *http.Request) {