query

package
v3.23.0 Latest Latest
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 Go to latest Published: Jul 26, 2020 License: MIT Imports: 34 Imported by: 0

Documentation

Overview

Package query provides a parser for the right-hand side query part of the bloblang spec. This is useful as a separate package as it is used in isolation within interpolation functions.

Index

Constants

This section is empty.

Variables

View Source 
var ErrDivideByZero = errors.New("attempted to divide by zero")

ErrDivideByZero occurs when an arithmetic operator is prevented from dividing a value by zero.

Functions

func ExecToBytes added in v3.14.0 

func ExecToBytes(fn Function, ctx FunctionContext) []byte

ExecToBytes returns a byte slice from a function exection.

func ExecToString added in v3.14.0 

func ExecToString(fn Function, ctx FunctionContext) string

ExecToString returns a string from a function exection.

func IClone added in v3.13.0 

func IClone(root interface{}) interface{}

IClone performs a deep copy of a generic value.

func IGetBool added in v3.15.0 

func IGetBool(v interface{}) (bool, error)

IGetBool takes a boxed value and attempts to extract a boolean from it.

func IGetInt added in v3.15.0 

func IGetInt(v interface{}) (int64, error)

IGetInt takes a boxed value and attempts to extract an integer (int64) from it.

func IGetNumber added in v3.13.0 

func IGetNumber(v interface{}) (float64, error)

IGetNumber takes a boxed value and attempts to extract a number (float64) from it.

func IGetString added in v3.16.0 

func IGetString(v interface{}) (string, error)

IGetString takes a boxed value and attempts to return a string value. Returns an error if the value is not a string or byte slice.

func IIsNull added in v3.13.0 

func IIsNull(i interface{}) bool

IIsNull returns whether a bloblang type is null, this includes Delete and Nothing types.

func ISanitize added in v3.13.0 

func ISanitize(i interface{}) interface{}

ISanitize takes a boxed value of any type and attempts to convert it into one of the following types: string, []byte, int64, uint64, float64, bool, []interface{}, map[string]interface{}, Delete, Nothing.

func IToBool added in v3.16.0 

func IToBool(v interface{}) (bool, error)

IToBool takes a boxed value and attempts to extract a boolean from it or parse it into a bool.

func IToBytes added in v3.13.0 

func IToBytes(i interface{}) []byte

IToBytes takes a boxed value of any type and attempts to convert it into a byte slice.

func IToNumber added in v3.16.0 

func IToNumber(v interface{}) (float64, error)

IToNumber takes a boxed value and attempts to extract a number (float64) from it or parse one.

func IToString added in v3.13.0 

func IToString(i interface{}) string

IToString takes a boxed value of any type and attempts to convert it into a string.

func ListFunctions added in v3.14.0 

func ListFunctions() []string

ListFunctions returns a slice of function names, sorted alphabetically.

func ListMethods added in v3.14.0 

func ListMethods() []string

ListMethods returns a slice of method names, sorted alphabetically.

func Parse 

func Parse(input []rune) parser.Result

Parse parses an input into a query.Function.

func ParseDeprecated 

func ParseDeprecated(input []rune) parser.Result

ParseDeprecated parses an input into a query.Function, but permits deprecated function interpolations. In order to support old functions this parser does not include field literals.

func RegisterFunction added in v3.13.0 

func RegisterFunction(name string, allowDynamicArgs bool, ctor FunctionCtor, checks ...ArgCheckFn) struct{}

RegisterFunction to be accessible from Bloblang queries. Returns an empty struct in order to allow inline calls.

func RegisterMethod added in v3.13.0 

func RegisterMethod(name string, allowDynamicArgs bool, ctor MethodCtor, checks ...ArgCheckFn) struct{}

RegisterMethod to be accessible from Bloblang queries. Returns an empty struct in order to allow inline calls.

Types

type ArgCheckFn added in v3.13.0 

type ArgCheckFn func(args []interface{}) error

ArgCheckFn is an optional argument type checker for a function constructor.

func ExpectAllStringArgs added in v3.17.0 

func ExpectAllStringArgs() ArgCheckFn

ExpectAllStringArgs returns an error if any argument is not a string type (or a byte slice that can be converted).

func ExpectAtLeastOneArg added in v3.14.0 

func ExpectAtLeastOneArg() ArgCheckFn

ExpectAtLeastOneArg returns an error unless >0 arguments are specified.

func ExpectBoolArg added in v3.15.0 

func ExpectBoolArg(i int) ArgCheckFn

ExpectBoolArg returns an error if an argument i is not a boolean type.

func ExpectFloatArg added in v3.15.0 

func ExpectFloatArg(i int) ArgCheckFn

ExpectFloatArg returns an error if an argument i is not a float type.

func ExpectIntArg added in v3.13.0 

func ExpectIntArg(i int) ArgCheckFn

ExpectIntArg returns an error if an argument i is not an integer type.

func ExpectNArgs added in v3.13.0 

func ExpectNArgs(i int) ArgCheckFn

ExpectNArgs returns an error unless exactly N arguments are specified.

func ExpectOneOrZeroArgs added in v3.13.0 

func ExpectOneOrZeroArgs() ArgCheckFn

ExpectOneOrZeroArgs returns an error if more than one arg is specified.

func ExpectStringArg added in v3.13.0 

func ExpectStringArg(i int) ArgCheckFn

ExpectStringArg returns an error if an argument i is not a string type (or a byte slice that can be converted).

type Delete added in v3.13.0 

type Delete *struct{}

Delete is a special type that serializes to `null` when forced but indicates a target should be deleted.

type ErrRecoverable 

type ErrRecoverable struct {
	Recovered interface{}
	Err       error
}

ErrRecoverable represents a function execution error that can optionally be recovered into a zero-value.

func (*ErrRecoverable) Error 

func (e *ErrRecoverable) Error() string

Error implements the standard error interface.

type Function 

type Function interface {
	// Execute this function for a message of a batch.
	Exec(ctx FunctionContext) (interface{}, error)
}

Function takes a set of contextual parameters and returns the result of the query.

func New added in v3.15.0 

func New(query string) (Function, error)

New creates a new query function from a query string.

type FunctionContext 

type FunctionContext struct {
	Value    *interface{}
	Maps     map[string]Function
	Vars     map[string]interface{}
	Index    int
	MsgBatch MessageBatch
	Legacy   bool
}

FunctionContext provides access to a root message, its index within the batch, and

type FunctionCtor added in v3.13.0 

type FunctionCtor func(args ...interface{}) (Function, error)

FunctionCtor constructs a new function from input arguments.

type MessageBatch added in v3.17.0 

type MessageBatch interface {
	Get(p int) types.Part
	Len() int
}

MessageBatch is an interface type to be given to a query function, it allows the function to resolve fields and metadata from a Benthos message batch.

type MethodCtor added in v3.13.0 

type MethodCtor func(target Function, args ...interface{}) (Function, error)

MethodCtor constructs a new method from a target function and input args.

type Nothing added in v3.13.0 

type Nothing *struct{}

Nothing is a special type that serializes to `null` when forced but indicates a query should be disregarded (and not mapped).

type TypeError added in v3.16.0 

type TypeError struct {
	Expected []ValueType
	Actual   ValueType
	Value    interface{}
}

TypeError represents an error where a value of a type was required for a function, method or operator but instead a different type was found.

func NewTypeError added in v3.16.0 

func NewTypeError(actual interface{}, exp ...ValueType) *TypeError

NewTypeError creates a new type error.

func (*TypeError) Error added in v3.16.0 

func (t *TypeError) Error() string

Error implements the standard error interface for TypeError.

type TypeMismatch added in v3.16.0 

type TypeMismatch struct {
	Left  ValueType
	Right ValueType
}

TypeMismatch represents an error where two values should be a comparable type but are not.

func NewTypeMismatch added in v3.16.0 

func NewTypeMismatch(left, right interface{}) *TypeMismatch

NewTypeMismatch creates a new type mismatch error.

func (*TypeMismatch) Error added in v3.16.0 

func (t *TypeMismatch) Error() string

Error implements the standard error interface.

type ValueType added in v3.16.0 

type ValueType string

ValueType represents a discrete value type supported by Bloblang queries. 

var (
	ValueString  ValueType = "string"
	ValueBytes   ValueType = "bytes"
	ValueNumber  ValueType = "number"
	ValueBool    ValueType = "bool"
	ValueArray   ValueType = "array"
	ValueObject  ValueType = "object"
	ValueNull    ValueType = "null"
	ValueDelete  ValueType = "delete"
	ValueNothing ValueType = "nothing"
	ValueUnknown ValueType = "unknown"
)

ValueType variants.

func ITypeOf added in v3.16.0 

func ITypeOf(i interface{}) ValueType

ITypeOf returns the type of a boxed value as a discrete ValueType. If the type of the value is unknown then ValueUnknown is returned.

Source Files

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