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 AreLabelsInWhiteList

    func AreLabelsInWhiteList(labels, whitelist Set) bool

      AreLabelsInWhiteList verifies if the provided label list is in the provided whitelist and returns true, otherwise false.

      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
                                                }

                                                  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().

                                                            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.

                                                              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.

                                                                      func (Set) AsSelectorPreValidated

                                                                      func (ls Set) AsSelectorPreValidated() Selector

                                                                        AsSelectorPreValidated converts labels into a selector, but assumes that labels are already validated and thus don't preform any validation. According to our measurements this is significantly faster in codepaths that matter at high scale.

                                                                        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
                                                                                )