gohugoio/hugo · error

invalid log level: %q, must be one of debug, warn, info or e

Error message

invalid log level: %q, must be one of debug, warn, info or error

What it means

Emitted while building the logger when the `--logLevel` flag value doesn't match one of the accepted names. Hugo lowercases the value and accepts only `debug`, `info`, `warn`/`warning`, and `error`; anything else aborts startup so a typo can't silently run with the wrong verbosity. Note `--logLevel` is ignored entirely in dev mode, which forces trace.

Source

Thrown at commands/commandeer.go:509

func (r *rootCommand) createLogger(running bool) (loggers.Logger, error) {
	level := logg.LevelWarn

	if r.devMode {
		level = logg.LevelTrace
	} else {
		if r.logLevel != "" {
			switch strings.ToLower(r.logLevel) {
			case "debug":
				level = logg.LevelDebug
			case "info":
				level = logg.LevelInfo
			case "warn", "warning":
				level = logg.LevelWarn
			case "error":
				level = logg.LevelError
			default:
				return nil, fmt.Errorf("invalid log level: %q, must be one of debug, warn, info or error", r.logLevel)
			}
		}
	}

	var logHookLast func(e *logg.Entry) error
	if r.panicOnWarning {
		logHookLast = loggers.PanicOnWarningHook
	}

	optsLogger := loggers.Options{
		DistinctLevel: logg.LevelWarn,
		Level:         level,
		StdOut:        r.StdOut,
		StdErr:        r.StdErr,
		StoreErrors:   running,
		HandlerPost:   logHookLast,
	}

View on GitHub ↗ (pinned to 8a468df065)

Solutions

1. Change the flag to one of the accepted values: `--logLevel info` (or debug, warn, error).
2. If you wanted trace-level output, there is no public trace level — use `--logLevel debug`.
3. In scripts, replace removed `--verbose`/`--debug` flags with `--logLevel info`/`--logLevel debug`.

Example fix

# before
hugo --logLevel verbose
# after
hugo --logLevel info

validLevels := map[string]bool{"debug": true, "info": true, "warn": true, "error": true}
if !validLevels[strings.ToLower(level)] {
    return fmt.Errorf("invalid --logLevel %q; use debug|info|warn|error", level)
}

func isValidLogLevel(s string) bool {
    switch strings.ToLower(s) {
    case "debug", "info", "warn", "error":
        return true
    }
    return false
}

When it happens

Trigger: Any Hugo invocation with `--logLevel <value>` where the lowercased value isn't debug/info/warn/warning/error — e.g. `--logLevel verbose`, `--logLevel trace`, `--logLevel DEBUG2`.

Common situations: Muscle memory from other tools using `trace`, `fatal`, or `verbose` levels; scripts written for the pre-0.114 `--verbose`/`--debug` flags migrated incorrectly; env-driven CI variables containing stray whitespace or wrong values.

Related errors

• invalid value for flag poll: %s
• language %q not found
• unsupported format: %q
• deploy not supported in this version of Hugo; install a rele
• target path "%s" exists but is not a directory

AI-assisted analysis of gohugoio/hugo@8a468df065 (2026-07-31). Data as JSON: /data/errors/28a3134f4edb15b3.json. Report an issue: GitHub ↗.