field

Documentation

Overview

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

Index

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

Types

type Expression

type Expression interface {
	// Bytes returns a byte slice representing the expression resolved for a
	// message
	// of a batch.
	Bytes(index int, msg Message) []byte

	// BytesLegacy is DEPRECATED - Instructs deprecated functions to disregard
	// index information.
	// TODO V4: Remove this.
	BytesLegacy(index int, msg Message) []byte

	// BytesEscaped returns a byte slice representing the expression resolved
	// for a message of a batch with the contents of resolved expressions
	// escaped.
	BytesEscaped(index int, msg Message) []byte

	// BytesEscapedLegacy is DEPRECATED - Instructs deprecated functions to
	// disregard index information.
	// TODO V4: Remove this.
	BytesEscapedLegacy(index int, msg Message) []byte

	// String returns a string representing the expression resolved for a
	// message of a batch.
	String(index int, msg Message) string

	// StringLegacy is DEPRECATED - Instructs deprecated functions to disregard
	// index information.
	// TODO V4: Remove this.
	StringLegacy(index int, msg Message) string
}

Expression represents a Benthos 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.

type Message

type Message interface {
	Get(p int) types.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, legacy bool) []byte

ResolveBytes returns a byte slice.

func (QueryResolver) ResolveString

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

ResolveString returns a string.

type Resolver

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

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, legacy bool) []byte

ResolveBytes returns a byte slice.

func (StaticResolver) ResolveString

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

ResolveString returns a string.