add relaxed env var name function

staging/src/k8s.io/apimachinery/pkg/util/validation/validation.go

@@ -21,6 +21,7 @@ import (
 	"math"
 	"regexp"
 	"strings"
+	"unicode"
 
 	"k8s.io/apimachinery/pkg/util/validation/field"
 	netutils "k8s.io/utils/net"
@@ -418,6 +419,9 @@ func IsHTTPHeaderName(value string) []string {
 const envVarNameFmt = "[-._a-zA-Z][-._a-zA-Z0-9]*"
 const envVarNameFmtErrMsg string = "a valid environment variable name must consist of alphabetic characters, digits, '_', '-', or '.', and must not start with a digit"
 
+// TODO(hirazawaui): Rename this when the RelaxedEnvironmentVariableValidation gate is removed.
+const relaxedEnvVarNameFmtErrMsg string = "a valid environment variable names must be printable ASCII characters other than '=' character"
+
 var envVarNameRegexp = regexp.MustCompile("^" + envVarNameFmt + "$")
 
 // IsEnvVarName tests if a string is a valid environment variable name.
@@ -431,6 +435,24 @@ func IsEnvVarName(value string) []string {
 	return errs
 }
 
+// IsRelaxedEnvVarName tests if a string is a valid environment variable name.
+func IsRelaxedEnvVarName(value string) []string {
+	var errs []string
+
+	if len(value) == 0 {
+		errs = append(errs, "environment variable name"+EmptyError())
+	}
+
+	for _, r := range value {
+		if r > unicode.MaxASCII || !unicode.IsPrint(r) || r == '=' {
+			errs = append(errs, relaxedEnvVarNameFmtErrMsg)
+			break
+		}
+	}
+
+	return errs
+}
+
 const configMapKeyFmt = `[-._a-zA-Z0-9]+`
 const configMapKeyErrMsg string = "a valid config key must consist of alphanumeric characters, '-', '_' or '.'"
 

staging/src/k8s.io/apimachinery/pkg/util/validation/validation_test.go

@@ -904,3 +904,30 @@ func TestIsDomainPrefixedPath(t *testing.T) {
 		}
 	}
 }
+
+func TestIsRelaxedEnvVarName(t *testing.T) {
+	goodValues := []string{
+		"-", ":", "_", "+a", ">a", "<a",
+		"a.", "a..", "*a", "%a", "?a",
+		"a:a", "a_a", "aAz", "~a", "|a",
+		"a0a", "a9", "/a", "a ", "#a",
+		"0a", "0 a", "'a", "(a", "@a",
+	}
+	for _, val := range goodValues {
+		if msgs := IsRelaxedEnvVarName(val); len(msgs) != 0 {
+			t.Errorf("expected true for '%s': %v", val, msgs)
+		}
+	}
+
+	badValues := []string{
+		"", "=", "a=", "1=a", "a=b", "#%=&&",
+		string(rune(1)) + "abc", string(rune(130)) + "abc",
+		"Ç ç", "Ä ä", "Ñ ñ", "Ø ø",
+	}
+
+	for _, val := range badValues {
+		if msgs := IsRelaxedEnvVarName(val); len(msgs) == 0 {
+			t.Errorf("expected false for '%s'", val)
+		}
+	}
+}