Initial checkin from CRI-O repo

Signed-off-by: Matthew Heon <matthew.heon@gmail.com>

3 files changed, 688 insertions, 0 deletions

diff --git a/vendor/k8s.io/apimachinery/pkg/util/validation/field/errors.go b/vendor/k8s.io/apimachinery/pkg/util/validation/field/errors.go
new file mode 100644
index 000000000..43c779a11
--- /dev/null
+++ b/vendor/k8s.io/apimachinery/pkg/util/validation/field/errors.go
@@ -0,0 +1,254 @@
+/*
+Copyright 2014 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 field
+
+import (
+	"fmt"
+	"reflect"
+	"strings"
+
+	utilerrors "k8s.io/apimachinery/pkg/util/errors"
+	"k8s.io/apimachinery/pkg/util/sets"
+)
+
+// Error is an implementation of the 'error' interface, which represents a
+// field-level validation error.
+type Error struct {
+	Type     ErrorType
+	Field    string
+	BadValue interface{}
+	Detail   string
+}
+
+var _ error = &Error{}
+
+// Error implements the error interface.
+func (v *Error) Error() string {
+	return fmt.Sprintf("%s: %s", v.Field, v.ErrorBody())
+}
+
+// ErrorBody returns the error message without the field name.  This is useful
+// for building nice-looking higher-level error reporting.
+func (v *Error) ErrorBody() string {
+	var s string
+	switch v.Type {
+	case ErrorTypeRequired, ErrorTypeForbidden, ErrorTypeTooLong, ErrorTypeInternal:
+		s = fmt.Sprintf("%s", v.Type)
+	default:
+		value := v.BadValue
+		valueType := reflect.TypeOf(value)
+		if value == nil || valueType == nil {
+			value = "null"
+		} else if valueType.Kind() == reflect.Ptr {
+			if reflectValue := reflect.ValueOf(value); reflectValue.IsNil() {
+				value = "null"
+			} else {
+				value = reflectValue.Elem().Interface()
+			}
+		}
+		switch t := value.(type) {
+		case int64, int32, float64, float32, bool:
+			// use simple printer for simple types
+			s = fmt.Sprintf("%s: %v", v.Type, value)
+		case string:
+			s = fmt.Sprintf("%s: %q", v.Type, t)
+		case fmt.Stringer:
+			// anything that defines String() is better than raw struct
+			s = fmt.Sprintf("%s: %s", v.Type, t.String())
+		default:
+			// fallback to raw struct
+			// TODO: internal types have panic guards against json.Marshalling to prevent
+			// accidental use of internal types in external serialized form.  For now, use
+			// %#v, although it would be better to show a more expressive output in the future
+			s = fmt.Sprintf("%s: %#v", v.Type, value)
+		}
+	}
+	if len(v.Detail) != 0 {
+		s += fmt.Sprintf(": %s", v.Detail)
+	}
+	return s
+}
+
+// ErrorType is a machine readable value providing more detail about why
+// a field is invalid.  These values are expected to match 1-1 with
+// CauseType in api/types.go.
+type ErrorType string
+
+// TODO: These values are duplicated in api/types.go, but there's a circular dep.  Fix it.
+const (
+	// ErrorTypeNotFound is used to report failure to find a requested value
+	// (e.g. looking up an ID).  See NotFound().
+	ErrorTypeNotFound ErrorType = "FieldValueNotFound"
+	// ErrorTypeRequired is used to report required values that are not
+	// provided (e.g. empty strings, null values, or empty arrays).  See
+	// Required().
+	ErrorTypeRequired ErrorType = "FieldValueRequired"
+	// ErrorTypeDuplicate is used to report collisions of values that must be
+	// unique (e.g. unique IDs).  See Duplicate().
+	ErrorTypeDuplicate ErrorType = "FieldValueDuplicate"
+	// ErrorTypeInvalid is used to report malformed values (e.g. failed regex
+	// match, too long, out of bounds).  See Invalid().
+	ErrorTypeInvalid ErrorType = "FieldValueInvalid"
+	// ErrorTypeNotSupported is used to report unknown values for enumerated
+	// fields (e.g. a list of valid values).  See NotSupported().
+	ErrorTypeNotSupported ErrorType = "FieldValueNotSupported"
+	// ErrorTypeForbidden is used to report valid (as per formatting rules)
+	// values which would be accepted under some conditions, but which are not
+	// permitted by the current conditions (such as security policy).  See
+	// Forbidden().
+	ErrorTypeForbidden ErrorType = "FieldValueForbidden"
+	// ErrorTypeTooLong is used to report that the given value is too long.
+	// This is similar to ErrorTypeInvalid, but the error will not include the
+	// too-long value.  See TooLong().
+	ErrorTypeTooLong ErrorType = "FieldValueTooLong"
+	// ErrorTypeInternal is used to report other errors that are not related
+	// to user input.  See InternalError().
+	ErrorTypeInternal ErrorType = "InternalError"
+)
+
+// String converts a ErrorType into its corresponding canonical error message.
+func (t ErrorType) String() string {
+	switch t {
+	case ErrorTypeNotFound:
+		return "Not found"
+	case ErrorTypeRequired:
+		return "Required value"
+	case ErrorTypeDuplicate:
+		return "Duplicate value"
+	case ErrorTypeInvalid:
+		return "Invalid value"
+	case ErrorTypeNotSupported:
+		return "Unsupported value"
+	case ErrorTypeForbidden:
+		return "Forbidden"
+	case ErrorTypeTooLong:
+		return "Too long"
+	case ErrorTypeInternal:
+		return "Internal error"
+	default:
+		panic(fmt.Sprintf("unrecognized validation error: %q", string(t)))
+	}
+}
+
+// NotFound returns a *Error indicating "value not found".  This is
+// used to report failure to find a requested value (e.g. looking up an ID).
+func NotFound(field *Path, value interface{}) *Error {
+	return &Error{ErrorTypeNotFound, field.String(), value, ""}
+}
+
+// Required returns a *Error indicating "value required".  This is used
+// to report required values that are not provided (e.g. empty strings, null
+// values, or empty arrays).
+func Required(field *Path, detail string) *Error {
+	return &Error{ErrorTypeRequired, field.String(), "", detail}
+}
+
+// Duplicate returns a *Error indicating "duplicate value".  This is
+// used to report collisions of values that must be unique (e.g. names or IDs).
+func Duplicate(field *Path, value interface{}) *Error {
+	return &Error{ErrorTypeDuplicate, field.String(), value, ""}
+}
+
+// Invalid returns a *Error indicating "invalid value".  This is used
+// to report malformed values (e.g. failed regex match, too long, out of bounds).
+func Invalid(field *Path, value interface{}, detail string) *Error {
+	return &Error{ErrorTypeInvalid, field.String(), value, detail}
+}
+
+// NotSupported returns a *Error indicating "unsupported value".
+// This is used to report unknown values for enumerated fields (e.g. a list of
+// valid values).
+func NotSupported(field *Path, value interface{}, validValues []string) *Error {
+	detail := ""
+	if validValues != nil && len(validValues) > 0 {
+		detail = "supported values: " + strings.Join(validValues, ", ")
+	}
+	return &Error{ErrorTypeNotSupported, field.String(), value, detail}
+}
+
+// Forbidden returns a *Error indicating "forbidden".  This is used to
+// report valid (as per formatting rules) values which would be accepted under
+// some conditions, but which are not permitted by current conditions (e.g.
+// security policy).
+func Forbidden(field *Path, detail string) *Error {
+	return &Error{ErrorTypeForbidden, field.String(), "", detail}
+}
+
+// TooLong returns a *Error indicating "too long".  This is used to
+// report that the given value is too long.  This is similar to
+// Invalid, but the returned error will not include the too-long
+// value.
+func TooLong(field *Path, value interface{}, maxLength int) *Error {
+	return &Error{ErrorTypeTooLong, field.String(), value, fmt.Sprintf("must have at most %d characters", maxLength)}
+}
+
+// InternalError returns a *Error indicating "internal error".  This is used
+// to signal that an error was found that was not directly related to user
+// input.  The err argument must be non-nil.
+func InternalError(field *Path, err error) *Error {
+	return &Error{ErrorTypeInternal, field.String(), nil, err.Error()}
+}
+
+// ErrorList holds a set of Errors.  It is plausible that we might one day have
+// non-field errors in this same umbrella package, but for now we don't, so
+// we can keep it simple and leave ErrorList here.
+type ErrorList []*Error
+
+// NewErrorTypeMatcher returns an errors.Matcher that returns true
+// if the provided error is a Error and has the provided ErrorType.
+func NewErrorTypeMatcher(t ErrorType) utilerrors.Matcher {
+	return func(err error) bool {
+		if e, ok := err.(*Error); ok {
+			return e.Type == t
+		}
+		return false
+	}
+}
+
+// ToAggregate converts the ErrorList into an errors.Aggregate.
+func (list ErrorList) ToAggregate() utilerrors.Aggregate {
+	errs := make([]error, 0, len(list))
+	errorMsgs := sets.NewString()
+	for _, err := range list {
+		msg := fmt.Sprintf("%v", err)
+		if errorMsgs.Has(msg) {
+			continue
+		}
+		errorMsgs.Insert(msg)
+		errs = append(errs, err)
+	}
+	return utilerrors.NewAggregate(errs)
+}
+
+func fromAggregate(agg utilerrors.Aggregate) ErrorList {
+	errs := agg.Errors()
+	list := make(ErrorList, len(errs))
+	for i := range errs {
+		list[i] = errs[i].(*Error)
+	}
+	return list
+}
+
+// Filter removes items from the ErrorList that match the provided fns.
+func (list ErrorList) Filter(fns ...utilerrors.Matcher) ErrorList {
+	err := utilerrors.FilterOut(list.ToAggregate(), fns...)
+	if err == nil {
+		return nil
+	}
+	// FilterOut takes an Aggregate and returns an Aggregate
+	return fromAggregate(err.(utilerrors.Aggregate))
+}
diff --git a/vendor/k8s.io/apimachinery/pkg/util/validation/field/path.go b/vendor/k8s.io/apimachinery/pkg/util/validation/field/path.go
new file mode 100644
index 000000000..2efc8eec7
--- /dev/null
+++ b/vendor/k8s.io/apimachinery/pkg/util/validation/field/path.go
@@ -0,0 +1,91 @@
+/*
+Copyright 2015 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 field
+
+import (
+	"bytes"
+	"fmt"
+	"strconv"
+)
+
+// Path represents the path from some root to a particular field.
+type Path struct {
+	name   string // the name of this field or "" if this is an index
+	index  string // if name == "", this is a subscript (index or map key) of the previous element
+	parent *Path  // nil if this is the root element
+}
+
+// NewPath creates a root Path object.
+func NewPath(name string, moreNames ...string) *Path {
+	r := &Path{name: name, parent: nil}
+	for _, anotherName := range moreNames {
+		r = &Path{name: anotherName, parent: r}
+	}
+	return r
+}
+
+// Root returns the root element of this Path.
+func (p *Path) Root() *Path {
+	for ; p.parent != nil; p = p.parent {
+		// Do nothing.
+	}
+	return p
+}
+
+// Child creates a new Path that is a child of the method receiver.
+func (p *Path) Child(name string, moreNames ...string) *Path {
+	r := NewPath(name, moreNames...)
+	r.Root().parent = p
+	return r
+}
+
+// Index indicates that the previous Path is to be subscripted by an int.
+// This sets the same underlying value as Key.
+func (p *Path) Index(index int) *Path {
+	return &Path{index: strconv.Itoa(index), parent: p}
+}
+
+// Key indicates that the previous Path is to be subscripted by a string.
+// This sets the same underlying value as Index.
+func (p *Path) Key(key string) *Path {
+	return &Path{index: key, parent: p}
+}
+
+// String produces a string representation of the Path.
+func (p *Path) String() string {
+	// make a slice to iterate
+	elems := []*Path{}
+	for ; p != nil; p = p.parent {
+		elems = append(elems, p)
+	}
+
+	// iterate, but it has to be backwards
+	buf := bytes.NewBuffer(nil)
+	for i := range elems {
+		p := elems[len(elems)-1-i]
+		if p.parent != nil && len(p.name) > 0 {
+			// This is either the root or it is a subscript.
+			buf.WriteString(".")
+		}
+		if len(p.name) > 0 {
+			buf.WriteString(p.name)
+		} else {
+			fmt.Fprintf(buf, "[%s]", p.index)
+		}
+	}
+	return buf.String()
+}
diff --git a/vendor/k8s.io/apimachinery/pkg/util/validation/validation.go b/vendor/k8s.io/apimachinery/pkg/util/validation/validation.go
new file mode 100644
index 000000000..b1fcc5708
--- /dev/null
+++ b/vendor/k8s.io/apimachinery/pkg/util/validation/validation.go
@@ -0,0 +1,343 @@
+/*
+Copyright 2014 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 validation
+
+import (
+	"fmt"
+	"math"
+	"net"
+	"regexp"
+	"strings"
+)
+
+const qnameCharFmt string = "[A-Za-z0-9]"
+const qnameExtCharFmt string = "[-A-Za-z0-9_.]"
+const qualifiedNameFmt string = "(" + qnameCharFmt + qnameExtCharFmt + "*)?" + qnameCharFmt
+const qualifiedNameErrMsg string = "must consist of alphanumeric characters, '-', '_' or '.', and must start and end with an alphanumeric character"
+const qualifiedNameMaxLength int = 63
+
+var qualifiedNameRegexp = regexp.MustCompile("^" + qualifiedNameFmt + "$")
+
+// IsQualifiedName tests whether the value passed is what Kubernetes calls a
+// "qualified name".  This is a format used in various places throughout the
+// system.  If the value is not valid, a list of error strings is returned.
+// Otherwise an empty list (or nil) is returned.
+func IsQualifiedName(value string) []string {
+	var errs []string
+	parts := strings.Split(value, "/")
+	var name string
+	switch len(parts) {
+	case 1:
+		name = parts[0]
+	case 2:
+		var prefix string
+		prefix, name = parts[0], parts[1]
+		if len(prefix) == 0 {
+			errs = append(errs, "prefix part "+EmptyError())
+		} else if msgs := IsDNS1123Subdomain(prefix); len(msgs) != 0 {
+			errs = append(errs, prefixEach(msgs, "prefix part ")...)
+		}
+	default:
+		return append(errs, "a qualified name "+RegexError(qualifiedNameErrMsg, qualifiedNameFmt, "MyName", "my.name", "123-abc")+
+			" with an optional DNS subdomain prefix and '/' (e.g. 'example.com/MyName')")
+	}
+
+	if len(name) == 0 {
+		errs = append(errs, "name part "+EmptyError())
+	} else if len(name) > qualifiedNameMaxLength {
+		errs = append(errs, "name part "+MaxLenError(qualifiedNameMaxLength))
+	}
+	if !qualifiedNameRegexp.MatchString(name) {
+		errs = append(errs, "name part "+RegexError(qualifiedNameErrMsg, qualifiedNameFmt, "MyName", "my.name", "123-abc"))
+	}
+	return errs
+}
+
+const labelValueFmt string = "(" + qualifiedNameFmt + ")?"
+const labelValueErrMsg string = "a valid label must be an empty string or consist of alphanumeric characters, '-', '_' or '.', and must start and end with an alphanumeric character"
+const LabelValueMaxLength int = 63
+
+var labelValueRegexp = regexp.MustCompile("^" + labelValueFmt + "$")
+
+// IsValidLabelValue tests whether the value passed is a valid label value.  If
+// the value is not valid, a list of error strings is returned.  Otherwise an
+// empty list (or nil) is returned.
+func IsValidLabelValue(value string) []string {
+	var errs []string
+	if len(value) > LabelValueMaxLength {
+		errs = append(errs, MaxLenError(LabelValueMaxLength))
+	}
+	if !labelValueRegexp.MatchString(value) {
+		errs = append(errs, RegexError(labelValueErrMsg, labelValueFmt, "MyValue", "my_value", "12345"))
+	}
+	return errs
+}
+
+const dns1123LabelFmt string = "[a-z0-9]([-a-z0-9]*[a-z0-9])?"
+const dns1123LabelErrMsg string = "a DNS-1123 label must consist of lower case alphanumeric characters or '-', and must start and end with an alphanumeric character"
+const DNS1123LabelMaxLength int = 63
+
+var dns1123LabelRegexp = regexp.MustCompile("^" + dns1123LabelFmt + "$")
+
+// IsDNS1123Label tests for a string that conforms to the definition of a label in
+// DNS (RFC 1123).
+func IsDNS1123Label(value string) []string {
+	var errs []string
+	if len(value) > DNS1123LabelMaxLength {
+		errs = append(errs, MaxLenError(DNS1123LabelMaxLength))
+	}
+	if !dns1123LabelRegexp.MatchString(value) {
+		errs = append(errs, RegexError(dns1123LabelErrMsg, dns1123LabelFmt, "my-name", "123-abc"))
+	}
+	return errs
+}
+
+const dns1123SubdomainFmt string = dns1123LabelFmt + "(\\." + dns1123LabelFmt + ")*"
+const dns1123SubdomainErrorMsg string = "a DNS-1123 subdomain must consist of lower case alphanumeric characters, '-' or '.', and must start and end with an alphanumeric character"
+const DNS1123SubdomainMaxLength int = 253
+
+var dns1123SubdomainRegexp = regexp.MustCompile("^" + dns1123SubdomainFmt + "$")
+
+// IsDNS1123Subdomain tests for a string that conforms to the definition of a
+// subdomain in DNS (RFC 1123).
+func IsDNS1123Subdomain(value string) []string {
+	var errs []string
+	if len(value) > DNS1123SubdomainMaxLength {
+		errs = append(errs, MaxLenError(DNS1123SubdomainMaxLength))
+	}
+	if !dns1123SubdomainRegexp.MatchString(value) {
+		errs = append(errs, RegexError(dns1123SubdomainErrorMsg, dns1123SubdomainFmt, "example.com"))
+	}
+	return errs
+}
+
+const dns1035LabelFmt string = "[a-z]([-a-z0-9]*[a-z0-9])?"
+const dns1035LabelErrMsg string = "a DNS-1035 label must consist of lower case alphanumeric characters or '-', and must start and end with an alphanumeric character"
+const DNS1035LabelMaxLength int = 63
+
+var dns1035LabelRegexp = regexp.MustCompile("^" + dns1035LabelFmt + "$")
+
+// IsDNS1035Label tests for a string that conforms to the definition of a label in
+// DNS (RFC 1035).
+func IsDNS1035Label(value string) []string {
+	var errs []string
+	if len(value) > DNS1035LabelMaxLength {
+		errs = append(errs, MaxLenError(DNS1035LabelMaxLength))
+	}
+	if !dns1035LabelRegexp.MatchString(value) {
+		errs = append(errs, RegexError(dns1035LabelErrMsg, dns1035LabelFmt, "my-name", "abc-123"))
+	}
+	return errs
+}
+
+// wildcard definition - RFC 1034 section 4.3.3.
+// examples:
+// - valid: *.bar.com, *.foo.bar.com
+// - invalid: *.*.bar.com, *.foo.*.com, *bar.com, f*.bar.com, *
+const wildcardDNS1123SubdomainFmt = "\\*\\." + dns1123SubdomainFmt
+const wildcardDNS1123SubdomainErrMsg = "a wildcard DNS-1123 subdomain must start with '*.', followed by a valid DNS subdomain, which must consist of lower case alphanumeric characters, '-' or '.' and end with an alphanumeric character"
+
+// IsWildcardDNS1123Subdomain tests for a string that conforms to the definition of a
+// wildcard subdomain in DNS (RFC 1034 section 4.3.3).
+func IsWildcardDNS1123Subdomain(value string) []string {
+	wildcardDNS1123SubdomainRegexp := regexp.MustCompile("^" + wildcardDNS1123SubdomainFmt + "$")
+
+	var errs []string
+	if len(value) > DNS1123SubdomainMaxLength {
+		errs = append(errs, MaxLenError(DNS1123SubdomainMaxLength))
+	}
+	if !wildcardDNS1123SubdomainRegexp.MatchString(value) {
+		errs = append(errs, RegexError(wildcardDNS1123SubdomainErrMsg, wildcardDNS1123SubdomainFmt, "*.example.com"))
+	}
+	return errs
+}
+
+const cIdentifierFmt string = "[A-Za-z_][A-Za-z0-9_]*"
+const identifierErrMsg string = "a valid C identifier must start with alphabetic character or '_', followed by a string of alphanumeric characters or '_'"
+
+var cIdentifierRegexp = regexp.MustCompile("^" + cIdentifierFmt + "$")
+
+// IsCIdentifier tests for a string that conforms the definition of an identifier
+// in C. This checks the format, but not the length.
+func IsCIdentifier(value string) []string {
+	if !cIdentifierRegexp.MatchString(value) {
+		return []string{RegexError(identifierErrMsg, cIdentifierFmt, "my_name", "MY_NAME", "MyName")}
+	}
+	return nil
+}
+
+// IsValidPortNum tests that the argument is a valid, non-zero port number.
+func IsValidPortNum(port int) []string {
+	if 1 <= port && port <= 65535 {
+		return nil
+	}
+	return []string{InclusiveRangeError(1, 65535)}
+}
+
+// Now in libcontainer UID/GID limits is 0 ~ 1<<31 - 1
+// TODO: once we have a type for UID/GID we should make these that type.
+const (
+	minUserID  = 0
+	maxUserID  = math.MaxInt32
+	minGroupID = 0
+	maxGroupID = math.MaxInt32
+)
+
+// IsValidGroupID tests that the argument is a valid Unix GID.
+func IsValidGroupID(gid int64) []string {
+	if minGroupID <= gid && gid <= maxGroupID {
+		return nil
+	}
+	return []string{InclusiveRangeError(minGroupID, maxGroupID)}
+}
+
+// IsValidUserID tests that the argument is a valid Unix UID.
+func IsValidUserID(uid int64) []string {
+	if minUserID <= uid && uid <= maxUserID {
+		return nil
+	}
+	return []string{InclusiveRangeError(minUserID, maxUserID)}
+}
+
+var portNameCharsetRegex = regexp.MustCompile("^[-a-z0-9]+$")
+var portNameOneLetterRegexp = regexp.MustCompile("[a-z]")
+
+// IsValidPortName check that the argument is valid syntax. It must be
+// non-empty and no more than 15 characters long. It may contain only [-a-z0-9]
+// and must contain at least one letter [a-z]. It must not start or end with a
+// hyphen, nor contain adjacent hyphens.
+//
+// Note: We only allow lower-case characters, even though RFC 6335 is case
+// insensitive.
+func IsValidPortName(port string) []string {
+	var errs []string
+	if len(port) > 15 {
+		errs = append(errs, MaxLenError(15))
+	}
+	if !portNameCharsetRegex.MatchString(port) {
+		errs = append(errs, "must contain only alpha-numeric characters (a-z, 0-9), and hyphens (-)")
+	}
+	if !portNameOneLetterRegexp.MatchString(port) {
+		errs = append(errs, "must contain at least one letter or number (a-z, 0-9)")
+	}
+	if strings.Contains(port, "--") {
+		errs = append(errs, "must not contain consecutive hyphens")
+	}
+	if len(port) > 0 && (port[0] == '-' || port[len(port)-1] == '-') {
+		errs = append(errs, "must not begin or end with a hyphen")
+	}
+	return errs
+}
+
+// IsValidIP tests that the argument is a valid IP address.
+func IsValidIP(value string) []string {
+	if net.ParseIP(value) == nil {
+		return []string{"must be a valid IP address, (e.g. 10.9.8.7)"}
+	}
+	return nil
+}
+
+const percentFmt string = "[0-9]+%"
+const percentErrMsg string = "a valid percent string must be a numeric string followed by an ending '%'"
+
+var percentRegexp = regexp.MustCompile("^" + percentFmt + "$")
+
+func IsValidPercent(percent string) []string {
+	if !percentRegexp.MatchString(percent) {
+		return []string{RegexError(percentErrMsg, percentFmt, "1%", "93%")}
+	}
+	return nil
+}
+
+const httpHeaderNameFmt string = "[-A-Za-z0-9]+"
+const httpHeaderNameErrMsg string = "a valid HTTP header must consist of alphanumeric characters or '-'"
+
+var httpHeaderNameRegexp = regexp.MustCompile("^" + httpHeaderNameFmt + "$")
+
+// IsHTTPHeaderName checks that a string conforms to the Go HTTP library's
+// definition of a valid header field name (a stricter subset than RFC7230).
+func IsHTTPHeaderName(value string) []string {
+	if !httpHeaderNameRegexp.MatchString(value) {
+		return []string{RegexError(httpHeaderNameErrMsg, httpHeaderNameFmt, "X-Header-Name")}
+	}
+	return nil
+}
+
+const configMapKeyFmt = `[-._a-zA-Z0-9]+`
+const configMapKeyErrMsg string = "a valid config key must consist of alphanumeric characters, '-', '_' or '.'"
+
+var configMapKeyRegexp = regexp.MustCompile("^" + configMapKeyFmt + "$")
+
+// IsConfigMapKey tests for a string that is a valid key for a ConfigMap or Secret
+func IsConfigMapKey(value string) []string {
+	var errs []string
+	if len(value) > DNS1123SubdomainMaxLength {
+		errs = append(errs, MaxLenError(DNS1123SubdomainMaxLength))
+	}
+	if !configMapKeyRegexp.MatchString(value) {
+		errs = append(errs, RegexError(configMapKeyErrMsg, configMapKeyFmt, "key.name", "KEY_NAME", "key-name"))
+	}
+	if value == "." {
+		errs = append(errs, `must not be '.'`)
+	} else if value == ".." {
+		errs = append(errs, `must not be '..'`)
+	} else if strings.HasPrefix(value, "..") {
+		errs = append(errs, `must not start with '..'`)
+	}
+	return errs
+}
+
+// MaxLenError returns a string explanation of a "string too long" validation
+// failure.
+func MaxLenError(length int) string {
+	return fmt.Sprintf("must be no more than %d characters", length)
+}
+
+// RegexError returns a string explanation of a regex validation failure.
+func RegexError(msg string, fmt string, examples ...string) string {
+	if len(examples) == 0 {
+		return msg + " (regex used for validation is '" + fmt + "')"
+	}
+	msg += " (e.g. "
+	for i := range examples {
+		if i > 0 {
+			msg += " or "
+		}
+		msg += "'" + examples[i] + "', "
+	}
+	msg += "regex used for validation is '" + fmt + "')"
+	return msg
+}
+
+// EmptyError returns a string explanation of a "must not be empty" validation
+// failure.
+func EmptyError() string {
+	return "must be non-empty"
+}
+
+func prefixEach(msgs []string, prefix string) []string {
+	for i := range msgs {
+		msgs[i] = prefix + msgs[i]
+	}
+	return msgs
+}
+
+// InclusiveRangeError returns a string explanation of a numeric "must be
+// between" validation failure.
+func InclusiveRangeError(lo, hi int) string {
+	return fmt.Sprintf(`must be between %d and %d, inclusive`, lo, hi)
+}