query

Documentation

Overview

Package query provides a parser for a custom query format:

abci.invoice.number=22 AND abci.invoice.owner=Ivan

See query.peg for the grammar, which is a https://en.wikipedia.org/wiki/Parsing_expression_grammar. More: https://github.com/PhilippeSigaud/Pegged/wiki/PEG-Basics

It has a support for numbers (integer and floating point), dates and times.

Index

• Constants
• func Pretty(pretty bool) func(*QueryParser) error
• func Size(size int) func(*QueryParser) error
• type Condition
• type Empty
  • func (Empty) Matches(tags map[string][]string) (bool, error)
  • func (Empty) String() string
• type Operator
• type Query
  • func MustParse(s string) *Query
  • func New(s string) (*Query, error)
  • func (q *Query) Conditions() ([]Condition, error)
  • func (q *Query) Matches(events map[string][]string) (bool, error)
  • func (q *Query) String() string
• type QueryParser
  • func (t *QueryParser) AST() *node32
  • func (t *QueryParser) Add(rule pegRule, begin, end, index uint32)
  • func (p *QueryParser) Init(options ...func(*QueryParser) error) error
  • func (p *QueryParser) Parse(rule ...int) error
  • func (t *QueryParser) PrettyPrintSyntaxTree(buffer string)
  • func (t *QueryParser) Print()
  • func (p *QueryParser) PrintSyntaxTree()
  • func (p *QueryParser) Reset()
  • func (p *QueryParser) SprintSyntaxTree() string
  • func (t *QueryParser) Tokens() []token32
  • func (t *QueryParser) Trim(length uint32)
  • func (p *QueryParser) WriteSyntaxTree(w io.Writer)

Constants

const (
	// DateLayout defines a layout for all dates (`DATE date`)
	DateLayout = "2006-01-02"
	// TimeLayout defines a layout for all times (`TIME time`)
	TimeLayout = time.RFC3339
)

Functions

func Pretty

func Pretty(pretty bool) func(*QueryParser) error

func Size

func Size(size int) func(*QueryParser) error

Types

type Condition

type Condition struct {
	CompositeKey string
	Op           Operator
	Operand      interface{}
}

Condition represents a single condition within a query and consists of composite key (e.g. "tx.gas"), operator (e.g. "=") and operand (e.g. "7").

type Empty

type Empty struct {
}

Empty query matches any set of events.

func (Empty) Matches

func (Empty) Matches(tags map[string][]string) (bool, error)

Matches always returns true.

func (Empty) String

func (Empty) String() string

type Operator

type Operator uint8

Operator is an operator that defines some kind of relation between composite key and operand (equality, etc.).

const (
	// "<="
	OpLessEqual Operator = iota
	// ">="
	OpGreaterEqual
	// "<"
	OpLess
	// ">"
	OpGreater
	// "="
	OpEqual
	// "CONTAINS"; used to check if a string contains a certain sub string.
	OpContains
	// "EXISTS"; used to check if a certain event attribute is present.
	OpExists
)

type Query

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

Query holds the query string and the query parser.

func MustParse

func MustParse(s string) *Query

MustParse turns the given string into a query or panics; for tests or others cases where you know the string is valid.

func New

func New(s string) (*Query, error)

New parses the given string and returns a query or error if the string is invalid.

func (*Query) Conditions

func (q *Query) Conditions() ([]Condition, error)

Conditions returns a list of conditions. It returns an error if there is any error with the provided grammar in the Query.

func (*Query) Matches

func (q *Query) Matches(events map[string][]string) (bool, error)

Matches returns true if the query matches against any event in the given set of events, false otherwise. For each event, a match exists if the query is matched against *any* value in a slice of values. An error is returned if any attempted event match returns an error.

For example, query "name=John" matches events = {"name": ["John", "Eric"]}. More examples could be found in parser_test.go and query_test.go.

func (*Query) String

func (q *Query) String() string

String returns the original string.

type QueryParser

type QueryParser struct {
	Buffer string

	Pretty bool
	// contains filtered or unexported fields
}

func (*QueryParser) AST

func (t *QueryParser) AST() *node32

func (*QueryParser) Add

func (t *QueryParser) Add(rule pegRule, begin, end, index uint32)

func (*QueryParser) Init

func (p *QueryParser) Init(options ...func(*QueryParser) error) error

func (*QueryParser) Parse

func (p *QueryParser) Parse(rule ...int) error

func (*QueryParser) PrettyPrintSyntaxTree

func (t *QueryParser) PrettyPrintSyntaxTree(buffer string)

func (*QueryParser) Print

func (t *QueryParser) Print()

func (*QueryParser) PrintSyntaxTree

func (p *QueryParser) PrintSyntaxTree()

func (*QueryParser) Reset

func (p *QueryParser) Reset()

func (*QueryParser) SprintSyntaxTree

func (p *QueryParser) SprintSyntaxTree() string

func (*QueryParser) Tokens

func (t *QueryParser) Tokens() []token32

func (*QueryParser) Trim

func (t *QueryParser) Trim(length uint32)

func (*QueryParser) WriteSyntaxTree

func (p *QueryParser) WriteSyntaxTree(w io.Writer)