bbgo_origin/pkg/exchange/okex/stream.go

package okex

import (
	"context"
	"net"
	"sync"
	"time"

	"github.com/c9s/bbgo/pkg/exchange/okex/okexapi"
	"github.com/c9s/bbgo/pkg/types"
	"github.com/gorilla/websocket"
)

//go:generate callbackgen -type Stream -interface
type Stream struct {
	types.StandardStream

	Client     *okexapi.RestClient
	ListenKey  string
	Conn       *websocket.Conn
	connLock   sync.Mutex
	reconnectC chan struct{}

	connCtx    context.Context
	connCancel context.CancelFunc

	publicOnly bool

	klineCallbacks []func()
}

func NewStream(client *okexapi.RestClient) *Stream {
	stream := &Stream{
		Client:     client,
		reconnectC: make(chan struct{}, 1),
	}
	return stream
}

func (s *Stream) SetPublicOnly() {
	s.publicOnly = true
}

func (s *Stream) Close() error {
	return nil
}

func (s *Stream) Connect(ctx context.Context) error {
	err := s.connect(ctx)
	if err != nil {
		return err
	}

	// start one re-connector goroutine with the base context
	go s.reconnector(ctx)

	s.EmitStart()
	return nil
}

func (s *Stream) emitReconnect() {
	select {
	case s.reconnectC <- struct{}{}:
	default:
	}
}

func (s *Stream) reconnector(ctx context.Context) {
	for {
		select {
		case <-ctx.Done():
			return

		case <-s.reconnectC:
			// ensure the previous context is cancelled
			if s.connCancel != nil {
				s.connCancel()
			}

			log.Warnf("received reconnect signal, reconnecting...")
			time.Sleep(3 * time.Second)

			if err := s.connect(ctx); err != nil {
				log.WithError(err).Errorf("connect error, try to reconnect again...")
				s.emitReconnect()
			}
		}
	}
}

func (s *Stream) dial() (*websocket.Conn, error) {
	var url string
	if s.publicOnly {
		url = okexapi.PublicWebSocketURL
	} else {
		url = okexapi.PrivateWebSocketURL
	}

	conn, _, err := websocket.DefaultDialer.Dial(url, nil)
	if err != nil {
		return nil, err
	}

	// use the default ping handler
	conn.SetPingHandler(nil)

	return conn, nil
}

func (s *Stream) connect(ctx context.Context) error {
	// should only start one connection one time, so we lock the mutex
	s.connLock.Lock()

	// create a new context
	s.connCtx, s.connCancel = context.WithCancel(ctx)

	if s.publicOnly {
		log.Infof("stream is set to public only mode")
	} else {
		log.Infof("request listen key for creating user data stream...")
	}

	// when in public mode, the listen key is an empty string
	conn, err := s.dial()
	if err != nil {
		s.connCancel()
		s.connLock.Unlock()
		return err
	}

	log.Infof("websocket connected")

	s.Conn = conn
	s.connLock.Unlock()

	s.EmitConnect()

	go s.read(s.connCtx)
	go s.ping(s.connCtx)
	return nil
}

func (s *Stream) read(ctx context.Context) {
	defer func() {
		if s.connCancel != nil {
			s.connCancel()
		}
		s.EmitDisconnect()
	}()

	for {
		select {

		case <-ctx.Done():
			return

		default:
			s.connLock.Lock()
			if err := s.Conn.SetReadDeadline(time.Now().Add(5 * time.Second)); err != nil {
				log.WithError(err).Errorf("set read deadline error: %s", err.Error())
			}

			mt, message, err := s.Conn.ReadMessage()
			s.connLock.Unlock()

			if err != nil {
				// if it's a network timeout error, we should re-connect
				switch err := err.(type) {

				// if it's a websocket related error
				case *websocket.CloseError:
					if err.Code == websocket.CloseNormalClosure {
						return
					}

					// for unexpected close error, we should re-connect
					// emit reconnect to start a new connection
					s.emitReconnect()
					return

				case net.Error:
					log.WithError(err).Error("network error")
					s.emitReconnect()
					return

				default:
					log.WithError(err).Error("unexpected connection error")
					s.emitReconnect()
					return
				}
			}

			// skip non-text messages
			if mt != websocket.TextMessage {
				continue
			}

			log.Debug(string(message))
		}
	}
}

func (s *Stream) ping(ctx context.Context) {
	pingTicker := time.NewTicker(15 * time.Second)
	defer pingTicker.Stop()

	for {
		select {

		case <-ctx.Done():
			log.Info("ping worker stopped")
			return

		case <-pingTicker.C:
			s.connLock.Lock()
			if err := s.Conn.WriteControl(websocket.PingMessage, []byte("hb"), time.Now().Add(3*time.Second)); err != nil {
				log.WithError(err).Error("ping error", err)
				s.emitReconnect()
			}
			s.connLock.Unlock()
		}
	}
}