feat: ✨ add config for log level

.env.example

@@ -79,6 +79,9 @@ RECONCILE_INTERVAL=60s
 # Coalesces rapid bursts (e.g. rolling restarts) into a single reconcile.
 DEBOUNCE_DELAY=5s
 
+# Log level for watcher output. Allowed: debug, info, warn, error
+LOG_LEVEL=info
+
 # ── Docker ────────────────────────────────────────────────────────────────────
 
 # Docker daemon endpoint. Leave empty to use the default Unix socket.

config.go

@@ -30,6 +30,7 @@ type Config struct {
 
 	ReconcileInterval time.Duration
 	DebounceDelay     time.Duration
+	LogLevel          string
 
 	RecordTTL         int
 	CloudflareAutoTTL bool
@@ -98,6 +99,13 @@ func LoadConfig() (*Config, error) {
 		return nil, fmt.Errorf("CF_AUTO_TTL: invalid boolean %q: %w", autoTTLStr, err)
 	}
 
+	cfg.LogLevel = strings.ToLower(envOrDefault("LOG_LEVEL", "info"))
+	switch cfg.LogLevel {
+	case "debug", "info", "warn", "error":
+	default:
+		return nil, fmt.Errorf("LOG_LEVEL: invalid value %q (allowed: debug, info, warn, error)", cfg.LogLevel)
+	}
+
 	cfg.ExcludeRouters = make(map[string]struct{})
 	if v := os.Getenv("EXCLUDE_ROUTERS"); v != "" {
 		for _, r := range strings.Split(v, ",") {

main.go

@@ -22,21 +22,28 @@ func main() {
 		return
 	}
 
-	slog.SetDefault(slog.New(slog.NewTextHandler(os.Stdout, &slog.HandlerOptions{
-		Level: slog.LevelInfo,
-	})))
-
 	cfg, err := LoadConfig()
 	if err != nil {
-		slog.Error("configuration error", "error", err)
+		fmt.Fprintln(os.Stderr, "configuration error:", err)
 		os.Exit(1)
 	}
 
+	logLevel, err := parseLogLevel(cfg.LogLevel)
+	if err != nil {
+		fmt.Fprintln(os.Stderr, "configuration error:", err)
+		os.Exit(1)
+	}
+
+	slog.SetDefault(slog.New(slog.NewTextHandler(os.Stdout, &slog.HandlerOptions{
+		Level: logLevel,
+	})))
+
 	slog.Info("traefik-dns-watcher starting",
 		"traefik_url", cfg.TraefikURL,
 		"zones", cfg.Zones,
 		"repo_path", cfg.RepoPath,
 		"dynamic_dir", cfg.DynamicDir,
+		"log_level", cfg.LogLevel,
 		"git_https_token_enabled", cfg.GitAuthToken != "",
 		"git_auth_username", cfg.GitAuthUsername,
 		"reconcile_interval", cfg.ReconcileInterval,
@@ -115,6 +122,21 @@ func main() {
 	slog.Info("traefik-dns-watcher stopped")
 }
 
+func parseLogLevel(v string) (slog.Level, error) {
+	switch strings.ToLower(v) {
+	case "debug":
+		return slog.LevelDebug, nil
+	case "info":
+		return slog.LevelInfo, nil
+	case "warn":
+		return slog.LevelWarn, nil
+	case "error":
+		return slog.LevelError, nil
+	default:
+		return 0, fmt.Errorf("LOG_LEVEL: invalid value %q (allowed: debug, info, warn, error)", v)
+	}
+}
+
 // maybeHandleGitAskpass serves username/password for git HTTPS auth in non-interactive mode.
 // This process mode is only enabled for git child processes that set TDW_GIT_ASKPASS=1.
 func maybeHandleGitAskpass() bool {