owasp-amass/amass · error

no log file specified

Error message

no log file specified

What it means

NewFileLogger builds a JSON slog.Logger writing to a file. This error is returned when the logfile argument is an empty string, indicating the caller did not select a log file even though the file logger was chosen.

Source

Thrown at internal/tools/log.go:38

)

func WriteLogMessage(l *slog.Logger, message string) error {
	record, err := afmt.JSONLogToRecord(message)
	if err != nil {
		return err
	}

	ctx := context.Background()
	if l.Handler().Enabled(ctx, record.Level) {
		return l.Handler().Handle(ctx, record)
	}

	return errors.New("logger handler is not enabled")
}

func NewFileLogger(dir, logfile string) (*slog.Logger, error) {
	if logfile == "" {
		return nil, fmt.Errorf("no log file specified")
	}

	if dir != "" {
		if err := os.MkdirAll(dir, 0640); err != nil {
			return nil, fmt.Errorf("failed to create the log directory: %v", err)
		}
	}

	f, err := os.OpenFile(filepath.Join(dir, logfile), os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644)
	if err != nil {
		return nil, fmt.Errorf("failed to open the log file: %v", err)
	}

	return slog.New(slog.NewJSONHandler(f, nil)), nil
}

func NewSyslogLogger() (*slog.Logger, error) {
	port := os.Getenv("SYSLOG_PORT")

View on GitHub (pinned to 79299dce87)

Solutions

1. Provide a non-empty logfile name, e.g. NewFileLogger(dir, "amass.log")
2. Set the log file path in the config file or pass the corresponding CLI flag
3. Verify the variable feeding the logfile argument is populated (print/inspect before the call)
4. Fall back to a sensible default filename when logfile is empty at the call site

Example fix

// before
logger, err := tools.NewFileLogger(dir, logfile) // logfile == ""
// after
if logfile == "" {
	logfile = "amass.log"
}
logger, err := tools.NewFileLogger(dir, logfile)

if logfile == "" {
	return errors.New("file logging selected but no log file name provided")
}

logger, err := tools.NewFileLogger(dir, logfile)
if err != nil && strings.Contains(err.Error(), "no log file specified") {
	logger, err = tools.NewFileLogger(dir, "default.log")
}

When it happens

Trigger: Calling NewFileLogger(dir, "") directly, or the CLI/config resolves to file logging (via selectLogger) with an empty log-file setting (e.g. -logfile flag not provided).

Common situations: Configuring the logger type as "file" but forgetting the log file path; an empty environment variable or config key feeding logfile; a refactor that dropped the default log file name.

Understand the failure class

Background: "missing required argument" and "the following required arguments were not provided": what required-argument errors mean and how to fix them — this error's family across 20 libraries.

Related errors

• zero names provided in the Organization
• missing the organization name
• failed to unmarshal the level text
• failed to provide a valid HTTP method
• logger handler is not enabled

AI-assisted analysis of owasp-amass/amass@79299dce87 (2026-09-06). Data as JSON: /api/errors/166a48a5cd43b7b4. Report an issue: GitHub.