101 lines
4 KiB
Go
101 lines
4 KiB
Go
/*
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Copyright 2025 The Kubernetes Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package content
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import (
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"regexp"
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)
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const dns1123LabelFmt string = "[a-z0-9]([-a-z0-9]*[a-z0-9])?"
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const dns1123LabelErrMsg string = "a lowercase RFC 1123 label must consist of lower case alphanumeric characters or '-', and must start and end with an alphanumeric character"
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// DNS1123LabelMaxLength is a label's max length in DNS (RFC 1123)
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const DNS1123LabelMaxLength int = 63
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var dns1123LabelRegexp = regexp.MustCompile("^" + dns1123LabelFmt + "$")
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// IsDNS1123Label tests for a string that conforms to the definition of a label in
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// DNS (RFC 1123).
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func IsDNS1123Label(value string) []string {
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var errs []string
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if len(value) > DNS1123LabelMaxLength {
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errs = append(errs, MaxLenError(DNS1123LabelMaxLength))
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}
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if !dns1123LabelRegexp.MatchString(value) {
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if dns1123SubdomainRegexp.MatchString(value) {
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// It was a valid subdomain and not a valid label. Since we
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// already checked length, it must be dots.
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errs = append(errs, "must not contain dots")
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} else {
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errs = append(errs, RegexError(dns1123LabelErrMsg, dns1123LabelFmt, "my-name", "123-abc"))
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}
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}
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return errs
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}
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const dns1123SubdomainFmt string = dns1123LabelFmt + "(\\." + dns1123LabelFmt + ")*"
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const dns1123SubdomainFmtCaseless string = "(?i)" + dns1123SubdomainFmt
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const dns1123SubdomainErrorMsg string = "a lowercase RFC 1123 subdomain must consist of lower case alphanumeric characters, '-' or '.', and must start and end with an alphanumeric character"
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const dns1123SubdomainCaselessErrorMsg string = "an RFC 1123 subdomain must consist of alphanumeric characters, '-' or '.', and must start and end with an alphanumeric character"
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// DNS1123SubdomainMaxLength is a subdomain's max length in DNS (RFC 1123)
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const DNS1123SubdomainMaxLength int = 253
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var dns1123SubdomainRegexp = regexp.MustCompile("^" + dns1123SubdomainFmt + "$")
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var dns1123SubdomainCaselessRegexp = regexp.MustCompile("^" + dns1123SubdomainFmtCaseless + "$")
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// IsDNS1123Subdomain tests for a string that conforms to the definition of a
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// subdomain in DNS (RFC 1123) lowercase.
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func IsDNS1123Subdomain(value string) []string {
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return isDNS1123Subdomain(value, false)
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}
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// IsDNS1123SubdomainCaseless tests for a string that conforms to the definition of a
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// subdomain in DNS (RFC 1123).
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//
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// Deprecated: API validation should never be caseless. Caseless validation is a vector
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// for bugs and failed uniqueness assumptions. For example, names like "foo.com" and
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// "FOO.COM" are both accepted as valid, but they are typically not treated as equal by
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// consumers (e.g. CSI and DRA driver names). This fails the "least surprise" principle and
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// can cause inconsistent behaviors.
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//
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// Note: This allows uppercase names but is not caseless — uppercase and lowercase are
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// treated as different values. Use IsDNS1123Subdomain for strict, lowercase validation
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// instead.
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func IsDNS1123SubdomainCaseless(value string) []string {
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return isDNS1123Subdomain(value, true)
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}
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func isDNS1123Subdomain(value string, caseless bool) []string {
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var errs []string
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if len(value) > DNS1123SubdomainMaxLength {
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errs = append(errs, MaxLenError(DNS1123SubdomainMaxLength))
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}
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errorMsg := dns1123SubdomainErrorMsg
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example := "example.com"
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regexp := dns1123SubdomainRegexp
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if caseless {
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errorMsg = dns1123SubdomainCaselessErrorMsg
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example = "Example.com"
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regexp = dns1123SubdomainCaselessRegexp
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}
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if !regexp.MatchString(value) {
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errs = append(errs, RegexError(errorMsg, dns1123SubdomainFmt, example))
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}
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return errs
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}
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