Documentation
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Overview ¶
Package labels implements a simple label system, parsing and matching selectors with sets of labels.
Index ¶
- func Conflicts(labels1, labels2 Set) bool
- func Equals(labels1, labels2 Set) bool
- func FormatLabels(labelMap map[string]string) string
- type ByKey
- type Labels
- type Lexer
- type Parser
- type ParserContext
- type Requirement
- func (in *Requirement) DeepCopy() *Requirement
- func (in *Requirement) DeepCopyInto(out *Requirement)
- func (r *Requirement) Key() string
- func (r *Requirement) Matches(ls Labels) bool
- func (r *Requirement) Operator() selection.Operator
- func (r *Requirement) String() string
- func (r *Requirement) Values() sets.String
- type Requirements
- type ScannedItem
- type Selector
- type Set
- type Token
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func Conflicts ¶
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 FormatLabels ¶
FormatLabels convert label map into plain string
Types ¶
type ByKey ¶
type ByKey []Requirement
ByKey sorts requirements by key to obtain deterministic parser
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
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 ¶
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) 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 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 Parse ¶
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 ¶
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 ¶
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 ¶ added in v0.19.0
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 ¶
Set is a map of label:value. It implements Labels.
func ConvertSelectorToLabelsMap ¶
ConvertSelectorToLabelsMap converts selector string to labels map and validates keys and values
func Merge ¶
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 ¶
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 ¶
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 ¶ added in v0.19.0
AsValidatedSelector converts labels into a selectors. The Set is validated client-side, which allows to catch errors early.
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 )
Source Files