field

Documentation

Overview

Package field implements a bloblang interpolation function templating syntax used in some dynamic fields within Bento. Only the query (right-hand side) part of the bloblang spec is supported within interpolation functions.

Index

• type Expression
  • func NewExpression(resolvers ...Resolver) *Expression
  • func (e *Expression) Bytes(index int, msg Message) ([]byte, error)
  • func (e *Expression) NumDynamicExpressions() int
  • func (e *Expression) String(index int, msg Message) (string, error)
• type Message
• type QueryResolver
  • func NewQueryResolver(fn query.Function) *QueryResolver
  • func (q QueryResolver) ResolveBytes(index int, msg Message, escaped bool) ([]byte, error)
  • func (q QueryResolver) ResolveString(index int, msg Message, escaped bool) (string, error)
• type Resolver
• type StaticResolver
  • func (s StaticResolver) ResolveBytes(index int, msg Message, escaped bool) ([]byte, error)
  • func (s StaticResolver) ResolveString(index int, msg Message, escaped bool) (string, error)

Types

type Expression

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

Expression represents a Bento dynamic field expression, used to configure string fields where the contents should change based on the contents of messages and other factors.

Each function here resolves the expression for a particular message of a batch, this is why an index is expected.

func NewExpression

func NewExpression(resolvers ...Resolver) *Expression

NewExpression creates a field expression from a slice of resolvers.

func (*Expression) Bytes

func (e *Expression) Bytes(index int, msg Message) ([]byte, error)

Bytes returns a byte slice representing the expression resolved for a message of a batch.

func (*Expression) NumDynamicExpressions

func (e *Expression) NumDynamicExpressions() int

NumDynamicExpressions returns the number of dynamic interpolation functions within the expression.

func (*Expression) String

func (e *Expression) String(index int, msg Message) (string, error)

String returns a string representing the expression resolved for a message of a batch.

type Message

type Message interface {
	Get(p int) *message.Part
	Len() int
}

Message is an interface type to be given to a function interpolator, it allows the function to resolve fields and metadata from a message.

type QueryResolver

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

QueryResolver executes a query and returns a string representation of the result.

func NewQueryResolver

func NewQueryResolver(fn query.Function) *QueryResolver

NewQueryResolver creates a field query resolver that returns the result of a query function.

func (QueryResolver) ResolveBytes

func (q QueryResolver) ResolveBytes(index int, msg Message, escaped bool) ([]byte, error)

ResolveBytes returns a byte slice.

func (QueryResolver) ResolveString

func (q QueryResolver) ResolveString(index int, msg Message, escaped bool) (string, error)

ResolveString returns a string.

type Resolver

type Resolver interface {
	ResolveString(index int, msg Message, escaped bool) (string, error)
	ResolveBytes(index int, msg Message, escaped bool) ([]byte, error)
}

Resolver is an interface for resolving a string containing Bloblang function interpolations into either a string or bytes.

type StaticResolver

type StaticResolver string

StaticResolver is a Resolver implementation that simply returns a static string.

func (StaticResolver) ResolveBytes

func (s StaticResolver) ResolveBytes(index int, msg Message, escaped bool) ([]byte, error)

ResolveBytes returns a byte slice.

func (StaticResolver) ResolveString

func (s StaticResolver) ResolveString(index int, msg Message, escaped bool) (string, error)

ResolveString returns a string.