Function scanThresholdExpression

metrics/thresholds_parser.go:144–153

scanThresholdExpression scans a threshold condition expression of the form: `aggregation_method operator value`. An invalid or unknown operator will produce an error. However, no assertions regarding either the left-hand side aggregation method nor the right-hand side value will be made: they will b

(input string)

// side value will be made: they will be returned as is, only trimmed from
// their spaces.
func scanThresholdExpression(input string) (string, string, string, error) {
	for _, op := range operatorTokens {
		left, right, _ := strings.Cut(input, op)
		if right != "" {
			return strings.TrimSpace(left), op, strings.TrimSpace(right), nil
		}
	}

	return "", "", "", fmt.Errorf("malformed threshold expression")
}

// Define accepted threshold expression aggregation tokens
// Percentile token `p(..)` is accepted too but handled separately.