build source

vendor/k8s.io/apimachinery/pkg/api/validate/content/dns.go

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