transport

Documentation

Overview

Package transport provides network transport interface. It allows to abstract our network from physical transport. It can either be IP based network or any other kind of packet courier (e.g. an industrial packet bus).

Package exports simple interfaces for easily defining new transports.

For now we provide two implementations of transport. The default is UTPTransport which using BitTorrent µTP protocol.

Usage:

var conn net.PacketConn
// get udp connection anywhere

tp, _ := transport.NewUTPTransport(conn)
msg := &packet.Packet{}

// Send the async queries and wait for a future
future, err := tp.SendRequest(msg)
if err != nil {
	panic(err)
}

select {
case response := <-future.Result():
	// Channel was closed
	if response == nil {
		panic("chanel closed unexpectedly")
	}

	// do something with response

case <-time.After(1 * time.Second):
	future.Cancel()
}

Index

• Variables
• func Resolve(cfg configuration.Transport, address string) (string, error)
• type CancelCallback
• type Future
  • func NewFuture(requestID network.RequestID, actor *host.Host, msg *packet.Packet, ...) Future
• type Transport
  • func NewQuicTransport(conn net.PacketConn, proxy relay.Proxy, publicAddress string) (Transport, error)
  • func NewTransport(cfg configuration.Transport, proxy relay.Proxy) (Transport, error)

Variables

var (
	// ErrTimeout is returned when the operation timeout is exceeded.
	ErrTimeout = errors.New("timeout")
	// ErrChannelClosed is returned when the input channel is closed.
	ErrChannelClosed = errors.New("channel closed")
)

Functions

func Resolve

func Resolve(cfg configuration.Transport, address string) (string, error)

Resolve resolves public address

Types

type CancelCallback

type CancelCallback func(Future)

CancelCallback is a callback function executed when cancelling Future.

type Future

type Future interface {

	// ID returns packet sequence number.
	ID() network.RequestID

	// Actor returns the initiator of the packet.
	Actor() *host.Host

	// Request returns origin request.
	Request() *packet.Packet

	// Result is a channel to listen for future result.
	Result() <-chan *packet.Packet

	// SetResult makes packet to appear in result channel.
	SetResult(*packet.Packet)

	// GetResult gets the future result from Result() channel with a timeout set to `duration`.
	GetResult(duration time.Duration) (*packet.Packet, error)

	// Cancel closes all channels and cleans up underlying structures.
	Cancel()
}

Future is network response future.

func NewFuture

func NewFuture(requestID network.RequestID, actor *host.Host, msg *packet.Packet, cancelCallback CancelCallback) Future

NewFuture creates new Future.

type Transport

type Transport interface {
	// SendRequest sends packet to destination. Sequence number is generated automatically.
	SendRequest(context.Context, *packet.Packet) (Future, error)

	// SendResponse sends response packet for request with passed request id.
	SendResponse(context.Context, network.RequestID, *packet.Packet) error

	// SendPacket low-level send packet without requestId and without spawning a waiting future
	SendPacket(ctx context.Context, p *packet.Packet) error

	// Listen starts thread to listen incoming packets.
	Listen(ctx context.Context) error

	// Stop gracefully stops listening.
	Stop()

	// Close disposing all transport underlying structures after stopped are called.
	Close()

	// Packets returns channel to listen incoming packets.
	Packets() <-chan *packet.Packet

	// Stopped returns signal channel to support graceful shutdown.
	Stopped() <-chan bool

	// PublicAddress returns PublicAddress
	PublicAddress() string
}

Transport is an interface for network transport.

func NewQuicTransport

func NewQuicTransport(conn net.PacketConn, proxy relay.Proxy, publicAddress string) (Transport, error)

func NewTransport

func NewTransport(cfg configuration.Transport, proxy relay.Proxy) (Transport, error)

NewTransport creates new Transport with particular configuration