thanos-io/thanos · error

cannot parse to a valid limit

Error message

cannot parse %q to a valid limit

What it means

Wraps strconv.Atoi in parseLimitParam: the query API limit parameter (e.g. series/label limit) is non-empty but not a base-10 integer. The offending raw string is quoted in the message; the caller rejects the request as bad data.

Solutions

1. Pass limit as a plain non-negative integer
2. Remove the limit parameter to disable limiting

Example fix

// before
GET /api/v1/labels?limit=1.5
// after
GET /api/v1/labels?limit=100

function validLimit(s) { return /^-?\d+$/.test(s); }

When it happens

Trigger: Calling an endpoint honoring parseLimitParam (e.g. /api/v1/labels, /api/v1/series) with `?limit=ten`, `limit=1.5`, or `limit=`-adjacent garbage that is non-empty but non-numeric.

Common situations: Passing fractional limits, strings with whitespace, or scientific notation; UIs sending placeholder text; scripting errors concatenating wrong variables into the URL.

Understand the failure class

Background: "Invalid query parameter" / "Failed to parse value of ...": fixing bad query string parameters across APIs — this error's family across 36 libraries.

Related errors

• cannot parse to a valid duration
• limit must be non-negative
• invalid metric metadata limit=
• cannot parse to a valid duration. It overflows int64
• parse federation labels

AI-assisted analysis of thanos-io/thanos@35b8b99117 (2026-09-07). Data as JSON: /api/errors/d344494d585b02df. Report an issue: GitHub.

Appendix: source

Thrown at pkg/api/query/v1.go:1624

			return 0, errors.Errorf("cannot parse %q to a valid duration. It overflows int64", s)
		}
		return time.Duration(ts), nil
	}
	if d, err := model.ParseDuration(s); err == nil {
		return time.Duration(d), nil
	}
	return 0, errors.Errorf("cannot parse %q to a valid duration", s)
}

// parseLimitParam returning 0 means no limit is to be applied.
func parseLimitParam(s string) (int, error) {
	if s == "" {
		return 0, nil
	}

	limit, err := strconv.Atoi(s)
	if err != nil {
		return 0, errors.Errorf("cannot parse %q to a valid limit", s)
	}
	if limit < 0 {
		return 0, errors.New("limit must be non-negative")
	}

	return limit, nil
}

// toHintLimit increases the API limit, as returned by parseLimitParam, by 1.
// This allows for emitting warnings when the results are truncated.
func toHintLimit(limit int) int {
	// 0 means no limit and avoid int overflow
	if limit > 0 && limit < math.MaxInt {
		return limit + 1
	}
	return limit
}

View on GitHub (pinned to 35b8b99117)