hibiken/asynq · error

cannot not parse option string

Error message

cannot not parse option string %q

What it means

parseOption's default branch rejects an option string it cannot recognize, returning 'cannot not parse option string %q' (note the doubled 'not', a typo in the library). Option strings must look like Name(args...) — e.g. Queue("email"), MaxRetry(5) — and anything else is invalid.

Solutions

1. Fix the option string to the Name(args...) form, e.g. Queue("default") instead of Queue.
2. Check for shell/config quoting that removed parentheses or quotes around arguments.
3. Confirm the option name is supported by the installed asynq version.
4. If passing a JSON-arg form, ensure it unmarshals to the expected shape (see the json.Unmarshal branch).

Example fix

// before
opts := []string{"MaxRetry", "Queue(email)"}
// after
opts := []string{"MaxRetry(5)", "Queue(\"email\")"}

if !regexp.MustCompile(`^[A-Za-z]\w*\(.*\)$`).MatchString(optStr) { return fmt.Errorf("malformed option %q", optStr) }

When it happens

Trigger: Passing a malformed option string to asynqtooling that supports string-based options (e.g. CLI-driven enqueue); missing parentheses/args like "MaxRetry" or "Queue"; unknown option name; unparseable JSON array arg for special forms.

Common situations: Hand-written option strings in config files or CLI flags; shell quoting that stripped parentheses; copying options between library versions with different option sets.

Understand the failure class

Background: "Invalid ... format", "must be in format X", "does not look like a ..." — invalid argument format errors across CLI tools and libraries — this error's family across 17 libraries.

Related errors

• batch enqueue does not support group tasks
• batch enqueue does not support unique tasks
• redis connection is shared so the Inspector can't be closed…
• asynq
• asynq

AI-assisted analysis of hibiken/asynq@d135f1439b (2026-09-07). Data as JSON: /api/errors/38246db4d74cab5f. Report an issue: GitHub.

Appendix: source

Thrown at inspector.go:1014

		if err != nil {
			return nil, err
		}
		return ProcessIn(d), nil
	case "Retention":
		d, err := time.ParseDuration(arg)
		if err != nil {
			return nil, err
		}
		return Retention(d), nil
	case "Header":
		var h [2]string
		err := json.Unmarshal([]byte(arg), &h)
		if err != nil {
			return nil, err
		}
		return Header(h[0], h[1]), nil
	default:
		return nil, fmt.Errorf("cannot not parse option string %q", s)
	}
}

func parseOptionFunc(s string) string {
	i := strings.Index(s, "(")
	return s[:i]
}

func parseOptionArg(s string) string {
	i := strings.Index(s, "(")
	if i >= 0 {
		j := strings.Index(s, ")")
		if j > i {
			return s[i+1 : j]
		}
	}
	return ""
}

View on GitHub (pinned to d135f1439b)