lambda

README

Overview

Documentation

Index

• func Start(handler interface{})
• func StartHandler(handler Handler)
• func StartHandlerFunc[TIn any, TOut any, H HandlerFunc[TIn, TOut]](handler H, options ...Option)
• func StartHandlerWithContext(ctx context.Context, handler Handler)
• func StartWithContext(ctx context.Context, handler interface{})
• func StartWithOptions(handler interface{}, options ...Option)
• type Function
  • func NewFunction(handler Handler) *Function
  • func (fn *Function) Invoke(req *messages.InvokeRequest, response *messages.InvokeResponse) error
  • func (fn *Function) Ping(req *messages.PingRequest, response *messages.PingResponse) error
• type Handler
  • func NewHandler(handlerFunc interface{}) Handler
  • func NewHandlerWithOptions(handlerFunc interface{}, options ...Option) Handler
• type HandlerFunc
• type Option
  • func WithContext(ctx context.Context) Option
  • func WithContextValue(key interface{}, value interface{}) Option
  • func WithDisallowUnknownFields(disallowUnknownFields bool) Option
  • func WithEnableSIGTERM(callbacks ...func()) Option
  • func WithSetEscapeHTML(escapeHTML bool) Option
  • func WithSetIndent(prefix, indent string) Option
  • func WithUseNumber(useNumber bool) Option

Functions

func Start

func Start(handler interface{})

Start takes a handler and talks to an internal Lambda endpoint to pass requests to the handler. If the handler does not match one of the supported types an appropriate error message will be returned to the caller. Start blocks, and does not return after being called.

Rules:

• handler must be a function
• handler may take between 0 and two arguments.
• if there are two arguments, the first argument must satisfy the "context.Context" interface.
• handler may return between 0 and two values.
• if there are two return values, the second return value must be an error.
• if there is one return value it must be an error.

Valid function signatures:

func ()
func (TIn)
func () error
func (TIn) error
func () (TOut, error)
func (TIn) (TOut, error)
func (context.Context)
func (context.Context) error
func (context.Context) (TOut, error)
func (context.Context, TIn)
func (context.Context, TIn) error
func (context.Context, TIn) (TOut, error)

Where "TIn" and "TOut" are types compatible with the "encoding/json" standard library. See https://golang.org/pkg/encoding/json/#Unmarshal for how deserialization behaves

"TOut" may also implement the io.Reader interface. If "TOut" is both json serializable and implements io.Reader, then the json serialization is used.

func StartHandler

func StartHandler(handler Handler)

StartHandler takes in a Handler wrapper interface which can be implemented either by a custom function or a struct.

Handler implementation requires a single "Invoke()" function:

func Invoke(context.Context, []byte) ([]byte, error)

Deprecated: use lambda.Start(handler) instead

func StartHandlerFunc

func StartHandlerFunc[TIn any, TOut any, H HandlerFunc[TIn, TOut]](handler H, options ...Option)

StartHandlerFunc is the same as StartWithOptions except that it takes a generic input so that the function signature can be validated at compile time.

func StartHandlerWithContext

func StartHandlerWithContext(ctx context.Context, handler Handler)

StartHandlerWithContext is the same as StartHandler except sets the base context for the function.

Handler implementation requires a single "Invoke()" function:

func Invoke(context.Context, []byte) ([]byte, error)

Deprecated: use lambda.StartWithOptions(handler, lambda.WithContext(ctx)) instead

func StartWithContext

func StartWithContext(ctx context.Context, handler interface{})

StartWithContext is the same as Start except sets the base context for the function.

Deprecated: use lambda.StartWithOptions(handler, lambda.WithContext(ctx)) instead

func StartWithOptions

func StartWithOptions(handler interface{}, options ...Option)

StartWithOptions is the same as Start after the application of any handler options specified

Types

type Function

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

Function struct which wrap the Handler

Deprecated: The Function type is public for the go1.x runtime internal use of the net/rpc package

func NewFunction

func NewFunction(handler Handler) *Function

NewFunction which creates a Function with a given Handler

Deprecated: The Function type is public for the go1.x runtime internal use of the net/rpc package

func (*Function) Invoke

func (fn *Function) Invoke(req *messages.InvokeRequest, response *messages.InvokeResponse) error

Invoke method try to perform a command given an InvokeRequest and an InvokeResponse

func (*Function) Ping

func (fn *Function) Ping(req *messages.PingRequest, response *messages.PingResponse) error

Ping method which given a PingRequest and a PingResponse parses the PingResponse

type Handler

type Handler interface {
	Invoke(ctx context.Context, payload []byte) ([]byte, error)
}

func NewHandler

func NewHandler(handlerFunc interface{}) Handler

NewHandler creates a base lambda handler from the given handler function. The returned Handler performs JSON serialization and deserialization, and delegates to the input handler function. The handler function parameter must satisfy the rules documented by Start. If handlerFunc is not a valid handler, the returned Handler simply reports the validation error.

func NewHandlerWithOptions

func NewHandlerWithOptions(handlerFunc interface{}, options ...Option) Handler

NewHandlerWithOptions creates a base lambda handler from the given handler function. The returned Handler performs JSON serialization and deserialization, and delegates to the input handler function. The handler function parameter must satisfy the rules documented by Start. If handlerFunc is not a valid handler, the returned Handler simply reports the validation error.

type HandlerFunc

type HandlerFunc[TIn, TOut any] interface {
	func(context.Context, TIn) (TOut, error)
}

HandlerFunc represents a valid input with two arguments and two returns as described by Start

type Option

type Option func(*handlerOptions)

func WithContext

func WithContext(ctx context.Context) Option

WithContext is a HandlerOption that sets the base context for all invocations of the handler.

Usage:

lambda.StartWithOptions(
 	func (ctx context.Context) (string, error) {
 		return ctx.Value("foo"), nil
 	},
 	lambda.WithContext(context.WithValue(context.Background(), "foo", "bar"))
)

func WithContextValue

func WithContextValue(key interface{}, value interface{}) Option

WithContextValue adds a value to the handler context. If a base context was set using WithContext, that base is used as the parent.

Usage:

lambda.StartWithOptions(
 	func (ctx context.Context) (string, error) {
 		return ctx.Value("foo"), nil
 	},
 	lambda.WithContextValue("foo", "bar")
)

func WithDisallowUnknownFields

func WithDisallowUnknownFields(disallowUnknownFields bool) Option

WithUseNumber sets the DisallowUnknownFields option on the underlying json decoder

Usage:

lambda.StartWithOptions(
	func (event any) (any, error) {
		return event, nil
	},
	lambda.WithDisallowUnknownFields(true)
)

func WithEnableSIGTERM

func WithEnableSIGTERM(callbacks ...func()) Option

WithEnableSIGTERM enables SIGTERM behavior within the Lambda platform on container spindown. SIGKILL will occur ~500ms after SIGTERM. Optionally, an array of callback functions to run on SIGTERM may be provided.

Usage:

lambda.StartWithOptions(
    func (event any) (any, error) {
		return event, nil
	},
	lambda.WithEnableSIGTERM(func() {
		log.Print("function container shutting down...")
	})
)

func WithSetEscapeHTML

func WithSetEscapeHTML(escapeHTML bool) Option

WithSetEscapeHTML sets the SetEscapeHTML argument on the underlying json encoder

Usage:

lambda.StartWithOptions(
	func () (string, error) {
		return "<html><body>hello!></body></html>", nil
	},
	lambda.WithSetEscapeHTML(true),
)

func WithSetIndent

func WithSetIndent(prefix, indent string) Option

WithSetIndent sets the SetIndent argument on the underling json encoder

Usage:

lambda.StartWithOptions(
	func (event any) (any, error) {
		return event, nil
	},
	lambda.WithSetIndent(">"," "),
)

func WithUseNumber

func WithUseNumber(useNumber bool) Option

WithUseNumber sets the UseNumber option on the underlying json decoder

Usage:

lambda.StartWithOptions(
	func (event any) (any, error) {
		return event, nil
	},
	lambda.WithUseNumber(true)
)