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 convert 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) (*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, 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.

                          func ParseToRequirements

                          func ParseToRequirements(selector string) ([]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) 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) (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.

                                                            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) (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.

                                                                        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
                                                                                  )