mirror of https://github.com/status-im/consul.git
31 lines
1.0 KiB
Go
31 lines
1.0 KiB
Go
// Copyright (c) HashiCorp, Inc.
|
|
// SPDX-License-Identifier: MPL-2.0
|
|
|
|
package dns
|
|
|
|
import (
|
|
"errors"
|
|
"regexp"
|
|
)
|
|
|
|
// matches valid DNS labels according to RFC 1123, should be at most 63
|
|
// characters according to the RFC
|
|
var validLabel = regexp.MustCompile(`^[a-zA-Z0-9]([a-zA-Z0-9\-]{0,61}[a-zA-Z0-9])?$`)
|
|
|
|
// IsValidLabel returns true if the string given is a valid DNS label (RFC 1123).
|
|
// Note: the only difference between RFC 1035 and RFC 1123 labels is that in
|
|
// RFC 1123 labels can begin with a number.
|
|
func IsValidLabel(name string) bool {
|
|
return validLabel.MatchString(name)
|
|
}
|
|
|
|
// ValidateLabel is similar to IsValidLabel except it returns an error
|
|
// instead of false when name is not a valid DNS label. The error will contain
|
|
// reference to what constitutes a valid DNS label.
|
|
func ValidateLabel(name string) error {
|
|
if !IsValidLabel(name) {
|
|
return errors.New("a valid DNS label must consist of lower case alphanumeric characters or '-', and must start and end with an alphanumeric character")
|
|
}
|
|
return nil
|
|
}
|