labels

package
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 Go to latest Published: Sep 4, 2023 License: MIT Imports: 10 Imported by: 0

Documentation

Overview

Package labels implements a simple label system, parsing and matching selectors with sets of labels.

Index

Constants

This section is empty.

Variables

This section is empty.

Functions

func Conflicts 

func Conflicts(labels1, labels2 Set) bool

Conflicts takes 2 maps and returns true if there a key match between the maps but the value doesn't match, and returns false in other cases

func Equals 

func Equals(labels1, labels2 Set) bool

Equals returns true if the given maps are equal

func FormatLabels 

func FormatLabels(labelMap map[string]string) string

FormatLabels converts label map into plain string

Types

type ByKey 

type ByKey []Requirement

ByKey sorts requirements by key to obtain deterministic parser

func (ByKey) Len 

func (a ByKey) Len() int

func (ByKey) Less 

func (a ByKey) Less(i, j int) bool

func (ByKey) Swap 

func (a ByKey) Swap(i, j int)

type Labels 

type Labels interface {
	// Has returns whether the provided label exists.
	Has(label string) (exists bool)

	// Get returns the value for the provided label.
	Get(label string) (value string)
}

Labels allows you to present labels independently from their storage.

type Lexer 

type Lexer struct {
	// contains filtered or unexported fields
}

Lexer represents the Lexer struct for label selector. It contains necessary informationt to tokenize the input string

func (*Lexer) Lex 

func (l *Lexer) Lex() (tok Token, lit string)

Lex returns a pair of Token and the literal literal is meaningfull only for IdentifierToken token

type Parser 

type Parser struct {
	// contains filtered or unexported fields
}

Parser data structure contains the label selector parser data structure

type ParserContext 

type ParserContext int

ParserContext represents context during parsing: some literal for example 'in' and 'notin' can be recognized as operator for example 'x in (a)' but it can be recognized as value for example 'value in (in)' 

const (
	// KeyAndOperator represents key and operator
	KeyAndOperator ParserContext = iota
	// Values represents values
	Values
)

type Requirement 

type Requirement struct {
	// contains filtered or unexported fields
}

Requirement contains values, a key, and an operator that relates the key and values. The zero value of Requirement is invalid. Requirement implements both set based match and exact match Requirement should be initialized via NewRequirement constructor for creating a valid Requirement. +k8s:deepcopy-gen=true

func NewRequirement 

func NewRequirement(key string, op selection.Operator, vals []string, opts ...field.PathOption) (*Requirement, error)

NewRequirement is the constructor for a Requirement. If any of these rules is violated, an error is returned:

  1. The operator can only be In, NotIn, Equals, DoubleEquals, Gt, Lt, NotEquals, Exists, or DoesNotExist.
  2. If the operator is In or NotIn, the values set must be non-empty.
  3. If the operator is Equals, DoubleEquals, or NotEquals, the values set must contain one value.
  4. If the operator is Exists or DoesNotExist, the value set must be empty.
  5. If the operator is Gt or Lt, the values set must contain only one value, which will be interpreted as an integer.
  6. The key is invalid due to its length, or sequence of characters. See validateLabelKey for more details.

The empty string is a valid value in the input values set. Returned error, if not nil, is guaranteed to be an aggregated field.ErrorList

func ParseToRequirements 

func ParseToRequirements(selector string, opts ...field.PathOption) ([]Requirement, error)

ParseToRequirements takes a string representing a selector and returns a list of requirements. This function is suitable for those callers that perform additional processing on selector requirements. See the documentation for Parse() function for more details. TODO: Consider exporting the internalSelector type instead.

func (*Requirement) DeepCopy 

func (in *Requirement) DeepCopy() *Requirement

DeepCopy is an autogenerated deepcopy function, copying the receiver, creating a new Requirement.

func (*Requirement) DeepCopyInto 

func (in *Requirement) DeepCopyInto(out *Requirement)

DeepCopyInto is an autogenerated deepcopy function, copying the receiver, writing into out. in must be non-nil.

func (Requirement) Equal 

func (r Requirement) Equal(x Requirement) bool

Equal checks the equality of requirement.

func (*Requirement) Key 

func (r *Requirement) Key() string

Key returns requirement key

func (*Requirement) Matches 

func (r *Requirement) Matches(ls Labels) bool

Matches returns true if the Requirement matches the input Labels. There is a match in the following cases:

  1. The operator is Exists and Labels has the Requirement's key.
  2. The operator is In, Labels has the Requirement's key and Labels' value for that key is in Requirement's value set.
  3. The operator is NotIn, Labels has the Requirement's key and Labels' value for that key is not in Requirement's value set.
  4. The operator is DoesNotExist or NotIn and Labels does not have the Requirement's key.
  5. The operator is GreaterThanOperator or LessThanOperator, and Labels has the Requirement's key and the corresponding value satisfies mathematical inequality.

func (*Requirement) Operator 

func (r *Requirement) Operator() selection.Operator

Operator returns requirement operator

func (*Requirement) String 

func (r *Requirement) String() string

String returns a human-readable string that represents this Requirement. If called on an invalid Requirement, an error is returned. See NewRequirement for creating a valid Requirement.

func (*Requirement) Values 

func (r *Requirement) Values() sets.String

Values returns requirement values

type Requirements 

type Requirements []Requirement

Requirements is AND of all requirements.

type ScannedItem 

type ScannedItem struct {
	// contains filtered or unexported fields
}

ScannedItem contains the Token and the literal produced by the lexer.

type Selector 

type Selector interface {
	// Matches returns true if this selector matches the given set of labels.
	Matches(Labels) bool

	// Empty returns true if this selector does not restrict the selection space.
	Empty() bool

	// String returns a human readable string that represents this selector.
	String() string

	// Add adds requirements to the Selector
	Add(r ...Requirement) Selector

	// Requirements converts this interface into Requirements to expose
	// more detailed selection information.
	// If there are querying parameters, it will return converted requirements and selectable=true.
	// If this selector doesn't want to select anything, it will return selectable=false.
	Requirements() (requirements Requirements, selectable bool)

	// Make a deep copy of the selector.
	DeepCopySelector() Selector

	// RequiresExactMatch allows a caller to introspect whether a given selector
	// requires a single specific label to be set, and if so returns the value it
	// requires.
	RequiresExactMatch(label string) (value string, found bool)
}

Selector represents a label selector.

func Everything 

func Everything() Selector

Everything returns a selector that matches all labels.

func NewSelector 

func NewSelector() Selector

NewSelector returns a nil selector

func Nothing 

func Nothing() Selector

Nothing returns a selector that matches no labels

func Parse 

func Parse(selector string, opts ...field.PathOption) (Selector, error)

Parse takes a string representing a selector and returns a selector object, or an error. This parsing function differs from ParseSelector as they parse different selectors with different syntaxes. The input will cause an error if it does not follow this form: 

<selector-syntax>         ::= <requirement> | <requirement> "," <selector-syntax>
<requirement>             ::= [!] KEY [ <set-based-restriction> | <exact-match-restriction> ]
<set-based-restriction>   ::= "" | <inclusion-exclusion> <value-set>
<inclusion-exclusion>     ::= <inclusion> | <exclusion>
<exclusion>               ::= "notin"
<inclusion>               ::= "in"
<value-set>               ::= "(" <values> ")"
<values>                  ::= VALUE | VALUE "," <values>
<exact-match-restriction> ::= ["="|"=="|"!="] VALUE

KEY is a sequence of one or more characters following [ DNS_SUBDOMAIN "/" ] DNS_LABEL. Max length is 63 characters. VALUE is a sequence of zero or more characters "([A-Za-z0-9_-\.])". Max length is 63 characters. Delimiter is white space: (' ', '\t') Example of valid syntax: 

"x in (foo,,baz),y,z notin ()"

Note:

  1. Inclusion - " in " - denotes that the KEY exists and is equal to any of the VALUEs in its requirement
  2. Exclusion - " notin " - denotes that the KEY is not equal to any of the VALUEs in its requirement or does not exist
  3. The empty string is a valid VALUE
  4. A requirement with just a KEY - as in "y" above - denotes that the KEY exists and can be any VALUE.
  5. A requirement with just !KEY requires that the KEY not exist.

func SelectorFromSet 

func SelectorFromSet(ls Set) Selector

SelectorFromSet returns a Selector which will match exactly the given Set. A nil and empty Sets are considered equivalent to Everything(). It does not perform any validation, which means the server will reject the request if the Set contains invalid values.

func SelectorFromValidatedSet 

func SelectorFromValidatedSet(ls Set) Selector

SelectorFromValidatedSet returns a Selector which will match exactly the given Set. A nil and empty Sets are considered equivalent to Everything(). It assumes that Set is already validated and doesn't do any validation. Note: this method copies the Set; if the Set is immutable, consider wrapping it with ValidatedSetSelector instead, which does not copy.

func ValidatedSelectorFromSet 

func ValidatedSelectorFromSet(ls Set) (Selector, error)

ValidatedSelectorFromSet returns a Selector which will match exactly the given Set. A nil and empty Sets are considered equivalent to Everything(). The Set is validated client-side, which allows to catch errors early.

type Set 

type Set map[string]string

Set is a map of label:value. It implements Labels.

func ConvertSelectorToLabelsMap 

func ConvertSelectorToLabelsMap(selector string, opts ...field.PathOption) (Set, error)

ConvertSelectorToLabelsMap converts selector string to labels map and validates keys and values

func Merge 

func Merge(labels1, labels2 Set) Set

Merge combines given maps, and does not check for any conflicts between the maps. In case of conflicts, second map (labels2) wins

func (Set) AsSelector 

func (ls Set) AsSelector() Selector

AsSelector converts labels into a selectors. It does not perform any validation, which means the server will reject the request if the Set contains invalid values.

func (Set) AsSelectorPreValidated 

func (ls Set) AsSelectorPreValidated() Selector

AsSelectorPreValidated converts labels into a selector, but assumes that labels are already validated and thus doesn't perform any validation. According to our measurements this is significantly faster in codepaths that matter at high scale. Note: this method copies the Set; if the Set is immutable, consider wrapping it with ValidatedSetSelector instead, which does not copy.

func (Set) AsValidatedSelector 

func (ls Set) AsValidatedSelector() (Selector, error)

AsValidatedSelector converts labels into a selectors. The Set is validated client-side, which allows to catch errors early.

func (Set) Get 

func (ls Set) Get(label string) string

Get returns the value in the map for the provided label.

func (Set) Has 

func (ls Set) Has(label string) bool

Has returns whether the provided label exists in the map.

func (Set) String 

func (ls Set) String() string

String returns all labels listed as a human readable string. Conveniently, exactly the format that ParseSelector takes.

type Token 

type Token int

Token represents constant definition for lexer token 

const (
	// ErrorToken represents scan error
	ErrorToken Token = iota
	// EndOfStringToken represents end of string
	EndOfStringToken
	// ClosedParToken represents close parenthesis
	ClosedParToken
	// CommaToken represents the comma
	CommaToken
	// DoesNotExistToken represents logic not
	DoesNotExistToken
	// DoubleEqualsToken represents double equals
	DoubleEqualsToken
	// EqualsToken represents equal
	EqualsToken
	// GreaterThanToken represents greater than
	GreaterThanToken
	// IdentifierToken represents identifier, e.g. keys and values
	IdentifierToken
	// InToken represents in
	InToken
	// LessThanToken represents less than
	LessThanToken
	// NotEqualsToken represents not equal
	NotEqualsToken
	// NotInToken represents not in
	NotInToken
	// OpenParToken represents open parenthesis
	OpenParToken
)

type ValidatedSetSelector 

type ValidatedSetSelector Set

ValidatedSetSelector wraps a Set, allowing it to implement the Selector interface. Unlike Set.AsSelectorPreValidated (which copies the input Set), this type simply wraps the underlying Set. As a result, it is substantially more efficient. A nil and empty Sets are considered equivalent to Everything().

Callers MUST ensure the underlying Set is not mutated, and that it is already validated. If these constraints are not met, Set.AsValidatedSelector should be preferred

None of the Selector methods mutate the underlying Set, but Add() and Requirements() convert to the less optimized version.

func (ValidatedSetSelector) Add 

func (s ValidatedSetSelector) Add(r ...Requirement) Selector

func (ValidatedSetSelector) DeepCopySelector 

func (s ValidatedSetSelector) DeepCopySelector() Selector

func (ValidatedSetSelector) Empty 

func (s ValidatedSetSelector) Empty() bool

func (ValidatedSetSelector) Matches 

func (s ValidatedSetSelector) Matches(labels Labels) bool

func (ValidatedSetSelector) Requirements 

func (s ValidatedSetSelector) Requirements() (requirements Requirements, selectable bool)

func (ValidatedSetSelector) RequiresExactMatch 

func (s ValidatedSetSelector) RequiresExactMatch(label string) (value string, found bool)

func (ValidatedSetSelector) String 

func (s ValidatedSetSelector) String() string

Source Files

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