pkg/exchange: implement bybit stream ping

pkg/exchange/bybit/convert_test.go

@@ -1,35 +1,19 @@
 package bybit
 
 import (
-	"context"
 	"fmt"
 	"math"
 	"strconv"
 	"testing"
 	"time"
 
-	"github.com/pkg/errors"
-	"github.com/stretchr/testify/assert"
-	"go.uber.org/multierr"
-
 	"github.com/c9s/bbgo/pkg/exchange/bybit/bybitapi"
 	v3 "github.com/c9s/bbgo/pkg/exchange/bybit/bybitapi/v3"
 	"github.com/c9s/bbgo/pkg/fixedpoint"
 	"github.com/c9s/bbgo/pkg/types"
+	"github.com/stretchr/testify/assert"
 )
 
-func TestU(t *testing.T) {
-	e := returnErr()
-
-	t.Log(errors.Is(e, context.DeadlineExceeded))
-
-}
-
-func returnErr() error {
-	var err error
-	return multierr.Append(multierr.Append(err, fmt.Errorf("got err: %w", context.DeadlineExceeded)), fmt.Errorf("GG"))
-}
-
 func TestToGlobalMarket(t *testing.T) {
 	// sample:
 	//{

pkg/exchange/bybit/stream.go

@@ -3,6 +3,7 @@ package bybit
 import (
 	"context"
 	"encoding/json"
+	"fmt"
 	"time"
 
 	"github.com/gorilla/websocket"
@@ -15,10 +16,16 @@ const (
 	// Bybit: To avoid network or program issues, we recommend that you send the ping heartbeat packet every 20 seconds
 	// to maintain the WebSocket connection.
 	pingInterval = 20 * time.Second
+
+	// spotArgsLimit can input up to 10 args for each subscription request sent to one connection.
+	spotArgsLimit = 10
 )
 
+//go:generate callbackgen -type Stream
 type Stream struct {
 	types.StandardStream
+
+	bookEventCallbacks []func(e BookEvent)
 }
 
 func NewStream() *Stream {
@@ -31,6 +38,8 @@ func NewStream() *Stream {
 	stream.SetDispatcher(stream.dispatchEvent)
 	stream.SetHeartBeat(stream.ping)
 
+	stream.OnConnect(stream.handlerConnect)
+	stream.OnBookEvent(stream.handleBookEvent)
 	return stream
 }
 
@@ -46,16 +55,43 @@ func (s *Stream) createEndpoint(_ context.Context) (string, error) {
 
 func (s *Stream) dispatchEvent(event interface{}) {
 	switch e := event.(type) {
-	case *WebSocketEvent:
+	case *WebSocketOpEvent:
 		if err := e.IsValid(); err != nil {
 			log.Errorf("invalid event: %v", err)
 		}
+
+	case *BookEvent:
+		s.EmitBookEvent(*e)
 	}
 }
 
 func (s *Stream) parseWebSocketEvent(in []byte) (interface{}, error) {
-	var resp WebSocketEvent
+	var e WsEvent
-	return &resp, json.Unmarshal(in, &resp)
+
+	err := json.Unmarshal(in, &e)
+	if err != nil {
+		return nil, err
+	}
+
+	switch {
+	case e.IsOp():
+		return e.WebSocketOpEvent, nil
+
+	case e.IsTopic():
+		switch getTopicType(e.Topic) {
+		case TopicTypeOrderBook:
+			var book BookEvent
+			err = json.Unmarshal(e.WebSocketTopicEvent.Data, &book)
+			if err != nil {
+				return nil, fmt.Errorf("failed to unmarshal data into BookEvent: %+v, : %w", string(e.WebSocketTopicEvent.Data), err)
+			}
+
+			book.Type = e.WebSocketTopicEvent.Type
+			return &book, nil
+		}
+	}
+
+	return nil, fmt.Errorf("unhandled websocket event: %+v", string(in))
 }
 
 // ping implements the Bybit text message of WebSocket PingPong.
@@ -94,3 +130,56 @@ func (s *Stream) ping(ctx context.Context, conn *websocket.Conn, cancelFunc cont
 		}
 	}
 }
+
+func (s *Stream) handlerConnect() {
+	if s.PublicOnly {
+		var topics []string
+
+		for _, subscription := range s.Subscriptions {
+			topic, err := convertSubscription(subscription)
+			if err != nil {
+				log.WithError(err).Errorf("subscription convert error")
+				continue
+			}
+
+			topics = append(topics, topic)
+		}
+		if len(topics) > spotArgsLimit {
+			log.Debugf("topics exceeds limit: %d, drop of: %v", spotArgsLimit, topics[spotArgsLimit:])
+			topics = topics[:spotArgsLimit]
+		}
+		log.Infof("subscribing channels: %+v", topics)
+		if err := s.Conn.WriteJSON(WebsocketOp{
+			Op:   "subscribe",
+			Args: topics,
+		}); err != nil {
+			log.WithError(err).Error("failed to send subscription request")
+		}
+	}
+}
+
+func convertSubscription(s types.Subscription) (string, error) {
+	switch s.Channel {
+	case types.BookChannel:
+		depth := types.DepthLevel1
+		if len(s.Options.Depth) > 0 && s.Options.Depth == types.DepthLevel50 {
+			depth = types.DepthLevel50
+		}
+		return genTopic(TopicTypeOrderBook, depth, s.Symbol), nil
+	}
+
+	return "", fmt.Errorf("unsupported stream channel: %s", s.Channel)
+}
+
+func (s *Stream) handleBookEvent(e BookEvent) {
+	orderBook := e.OrderBook()
+	switch {
+	// Occasionally, you'll receive "UpdateId"=1, which is a snapshot data due to the restart of
+	// the service. So please overwrite your local orderbook
+	case e.Type == DataTypeSnapshot || e.UpdateId.Int() == 1:
+		s.EmitBookSnapshot(orderBook)
+
+	case e.Type == DataTypeDelta:
+		s.EmitBookUpdate(orderBook)
+	}
+}

pkg/exchange/bybit/stream_callbacks.go

@@ -0,0 +1,15 @@
+// Code generated by "callbackgen -type Stream"; DO NOT EDIT.
+
+package bybit
+
+import ()
+
+func (s *Stream) OnBookEvent(cb func(e BookEvent)) {
+	s.bookEventCallbacks = append(s.bookEventCallbacks, cb)
+}
+
+func (s *Stream) EmitBookEvent(e BookEvent) {
+	for _, cb := range s.bookEventCallbacks {
+		cb(e)
+	}
+}

pkg/exchange/bybit/stream_test.go

@@ -0,0 +1,155 @@
+package bybit
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+
+	"github.com/c9s/bbgo/pkg/fixedpoint"
+	"github.com/c9s/bbgo/pkg/types"
+)
+
+func TestStream_parseWebSocketEvent(t *testing.T) {
+	s := Stream{}
+
+	t.Run("op", func(t *testing.T) {
+		input := `{
+		   "success":true,
+		   "ret_msg":"subscribe",
+		   "conn_id":"a403c8e5-e2b6-4edd-a8f0-1a64fa7227a5",
+		   "op":"subscribe"
+		}`
+		res, err := s.parseWebSocketEvent([]byte(input))
+		assert.NoError(t, err)
+		opEvent, ok := res.(*WebSocketOpEvent)
+		assert.True(t, ok)
+		expSucceeds := true
+		expRetMsg := "subscribe"
+		assert.Equal(t, WebSocketOpEvent{
+			Success: &expSucceeds,
+			RetMsg:  &expRetMsg,
+			ReqId:   nil,
+			ConnId:  "a403c8e5-e2b6-4edd-a8f0-1a64fa7227a5",
+			Op:      WsOpTypeSubscribe,
+			Args:    nil,
+		}, *opEvent)
+	})
+	t.Run("TopicTypeOrderBook with delta", func(t *testing.T) {
+		input := `{
+			   "topic":"orderbook.50.BTCUSDT",
+			   "ts":1691130685111,
+			   "type":"delta",
+			   "data":{
+			      "s":"BTCUSDT",
+			      "b":[
+
+			      ],
+			      "a":[
+			         [
+			            "29239.37",
+			            "0.082356"
+			         ],
+			         [
+			            "29236.1",
+			            "0"
+			         ]
+			      ],
+			      "u":1854104,
+			      "seq":10559247733
+			   }
+			}`
+
+		res, err := s.parseWebSocketEvent([]byte(input))
+		assert.NoError(t, err)
+		book, ok := res.(*BookEvent)
+		assert.True(t, ok)
+		assert.Equal(t, BookEvent{
+			Symbol: "BTCUSDT",
+			Bids:   nil,
+			Asks: types.PriceVolumeSlice{
+				{
+					fixedpoint.NewFromFloat(29239.37),
+					fixedpoint.NewFromFloat(0.082356),
+				},
+				{
+					fixedpoint.NewFromFloat(29236.1),
+					fixedpoint.NewFromFloat(0),
+				},
+			},
+			UpdateId:   fixedpoint.NewFromFloat(1854104),
+			SequenceId: fixedpoint.NewFromFloat(10559247733),
+			Type:       DataTypeDelta,
+		}, *book)
+	})
+
+	t.Run("Parse fails", func(t *testing.T) {
+		input := `{
+			   "topic":"orderbook.50.BTCUSDT",
+			   "ts":1691130685111,
+			   "type":"delta",
+			   "data":{
+					"GG": "test",
+			   }
+			}`
+
+		res, err := s.parseWebSocketEvent([]byte(input))
+		assert.Error(t, fmt.Errorf("failed to unmarshal data into BookEvent: %+v, : %w", `{
+					"GG": "test",
+			   }`, err), err)
+		assert.Equal(t, nil, res)
+	})
+}
+
+func Test_convertSubscription(t *testing.T) {
+	t.Run("BookChannel.DepthLevel1", func(t *testing.T) {
+		res, err := convertSubscription(types.Subscription{
+			Symbol:  "BTCUSDT",
+			Channel: types.BookChannel,
+			Options: types.SubscribeOptions{
+				Depth: types.DepthLevel1,
+			},
+		})
+		assert.NoError(t, err)
+		assert.Equal(t, genTopic(TopicTypeOrderBook, types.DepthLevel1, "BTCUSDT"), res)
+	})
+	t.Run("BookChannel. with default depth", func(t *testing.T) {
+		res, err := convertSubscription(types.Subscription{
+			Symbol:  "BTCUSDT",
+			Channel: types.BookChannel,
+		})
+		assert.NoError(t, err)
+		assert.Equal(t, genTopic(TopicTypeOrderBook, types.DepthLevel1, "BTCUSDT"), res)
+	})
+	t.Run("BookChannel.DepthLevel50", func(t *testing.T) {
+		res, err := convertSubscription(types.Subscription{
+			Symbol:  "BTCUSDT",
+			Channel: types.BookChannel,
+			Options: types.SubscribeOptions{
+				Depth: types.DepthLevel50,
+			},
+		})
+		assert.NoError(t, err)
+		assert.Equal(t, genTopic(TopicTypeOrderBook, types.DepthLevel50, "BTCUSDT"), res)
+	})
+	t.Run("BookChannel. not support depth, use default level 1", func(t *testing.T) {
+		res, err := convertSubscription(types.Subscription{
+			Symbol:  "BTCUSDT",
+			Channel: types.BookChannel,
+			Options: types.SubscribeOptions{
+				Depth: "20",
+			},
+		})
+		assert.NoError(t, err)
+		assert.Equal(t, genTopic(TopicTypeOrderBook, types.DepthLevel1, "BTCUSDT"), res)
+	})
+
+	t.Run("unsupported channel", func(t *testing.T) {
+		res, err := convertSubscription(types.Subscription{
+			Symbol:  "BTCUSDT",
+			Channel: "unsupported",
+		})
+		assert.Error(t, fmt.Errorf("unsupported stream channel: %s", "unsupported"), err)
+		assert.Equal(t, "", res)
+	})
+}

pkg/exchange/bybit/types.go

@@ -1,17 +1,42 @@
 package bybit
 
 import (
+	"encoding/json"
 	"fmt"
+	"strings"
+
+	"github.com/c9s/bbgo/pkg/fixedpoint"
+	"github.com/c9s/bbgo/pkg/types"
 )
 
+type WsEvent struct {
+	// "op" and "topic" are exclusive.
+	*WebSocketOpEvent
+	*WebSocketTopicEvent
+}
+
+func (w *WsEvent) IsOp() bool {
+	return w.WebSocketOpEvent != nil && w.WebSocketTopicEvent == nil
+}
+
+func (w *WsEvent) IsTopic() bool {
+	return w.WebSocketOpEvent == nil && w.WebSocketTopicEvent != nil
+}
+
 type WsOpType string
 
 const (
 	WsOpTypePing      WsOpType = "ping"
 	WsOpTypePong      WsOpType = "pong"
+	WsOpTypeSubscribe WsOpType = "subscribe"
 )
 
-type WebSocketEvent struct {
+type WebsocketOp struct {
+	Op   string   `json:"op"`
+	Args []string `json:"args"`
+}
+
+type WebSocketOpEvent struct {
 	Success *bool   `json:"success,omitempty"`
 	RetMsg  *string `json:"ret_msg,omitempty"`
 	ReqId   *string `json:"req_id,omitempty"`
@@ -21,19 +46,95 @@ type WebSocketEvent struct {
 	Args   []string `json:"args"`
 }
 
-func (w *WebSocketEvent) IsValid() error {
+func (w *WebSocketOpEvent) IsValid() error {
 	switch w.Op {
 	case WsOpTypePing:
 		// public event
 		if (w.Success != nil && !*w.Success) ||
 			(w.RetMsg != nil && WsOpType(*w.RetMsg) != WsOpTypePong) {
-			return fmt.Errorf("unexpeted response of pong: %#v", w)
+			return fmt.Errorf("unexpeted response of pong: %+v", w)
 		}
 		return nil
 	case WsOpTypePong:
 		// private event
 		return nil
+	case WsOpTypeSubscribe:
+		if w.Success != nil && !*w.Success {
+			return fmt.Errorf("unexpected subscribe result: %+v", w)
+		}
+		return nil
 	default:
-		return fmt.Errorf("unexpected op type: %#v", w)
+		return fmt.Errorf("unexpected op type: %+v", w)
 	}
 }
+
+type TopicType string
+
+const (
+	TopicTypeOrderBook TopicType = "orderbook"
+)
+
+type DataType string
+
+const (
+	DataTypeSnapshot DataType = "snapshot"
+	DataTypeDelta    DataType = "delta"
+)
+
+type WebSocketTopicEvent struct {
+	Topic string   `json:"topic"`
+	Type  DataType `json:"type"`
+	// The timestamp (ms) that the system generates the data
+	Ts   types.MillisecondTimestamp `json:"ts"`
+	Data json.RawMessage            `json:"data"`
+}
+
+// PriceVolumeSlice represents a slice of price and value.
+//
+// index 0 is Bid/Ask price.
+// index 1 is Bid/Ask size. The *delta data* has size=0, which means that all quotations for this price have been filled or cancelled
+type PriceVolumeSlice [2]fixedpoint.Value
+
+type BookEvent struct {
+	// Symbol name
+	Symbol string `json:"s"`
+	// Bids. For snapshot stream, the element is sorted by price in descending order
+	Bids types.PriceVolumeSlice `json:"b"`
+	// Asks. For snapshot stream, the element is sorted by price in ascending order
+	Asks types.PriceVolumeSlice `json:"a"`
+	// Update ID. Is a sequence. Occasionally, you'll receive "u"=1, which is a snapshot data due to the restart of
+	// the service. So please overwrite your local orderbook
+	UpdateId fixedpoint.Value `json:"u"`
+	// Cross sequence. You can use this field to compare different levels orderbook data, and for the smaller seq,
+	// then it means the data is generated earlier.
+	SequenceId fixedpoint.Value `json:"seq"`
+
+	// internal use
+	// Type can be one of snapshot or delta. Copied from WebSocketTopicEvent.Type
+	Type DataType
+}
+
+func (e *BookEvent) OrderBook() (snapshot types.SliceOrderBook) {
+	snapshot.Symbol = e.Symbol
+	snapshot.Bids = e.Bids
+	snapshot.Asks = e.Asks
+	return snapshot
+}
+
+const topicSeparator = "."
+
+func genTopic(in ...interface{}) string {
+	out := make([]string, len(in))
+	for k, v := range in {
+		out[k] = fmt.Sprintf("%v", v)
+	}
+	return strings.Join(out, topicSeparator)
+}
+
+func getTopicType(topic string) TopicType {
+	slice := strings.Split(topic, topicSeparator)
+	if len(slice) == 0 {
+		return ""
+	}
+	return TopicType(slice[0])
+}

pkg/exchange/bybit/types_test.go

@@ -5,6 +5,9 @@ import (
 	"testing"
 
 	"github.com/stretchr/testify/assert"
+
+	"github.com/c9s/bbgo/pkg/fixedpoint"
+	"github.com/c9s/bbgo/pkg/types"
 )
 
 func Test_parseWebSocketEvent(t *testing.T) {
@@ -16,9 +19,9 @@ func Test_parseWebSocketEvent(t *testing.T) {
 
 		expSucceeds := true
 		expRetMsg := string(WsOpTypePong)
-		e, ok := raw.(*WebSocketEvent)
+		e, ok := raw.(*WebSocketOpEvent)
 		assert.True(t, ok)
-		assert.Equal(t, &WebSocketEvent{
+		assert.Equal(t, &WebSocketOpEvent{
 			Success: &expSucceeds,
 			RetMsg:  &expRetMsg,
 			ConnId:  "a806f6c4-3608-4b6d-a225-9f5da975bc44",
@@ -39,9 +42,9 @@ func Test_parseWebSocketEvent(t *testing.T) {
 		expSucceeds := true
 		expRetMsg := string(WsOpTypePong)
 		expReqId := "b26704da-f5af-44c2-bdf7-935d6739e1a0"
-		e, ok := raw.(*WebSocketEvent)
+		e, ok := raw.(*WebSocketOpEvent)
 		assert.True(t, ok)
-		assert.Equal(t, &WebSocketEvent{
+		assert.Equal(t, &WebSocketOpEvent{
 			Success: &expSucceeds,
 			RetMsg:  &expRetMsg,
 			ConnId:  "a806f6c4-3608-4b6d-a225-9f5da975bc44",
@@ -59,9 +62,9 @@ func Test_parseWebSocketEvent(t *testing.T) {
 		raw, err := s.parseWebSocketEvent([]byte(msg))
 		assert.NoError(t, err)
 
-		e, ok := raw.(*WebSocketEvent)
+		e, ok := raw.(*WebSocketOpEvent)
 		assert.True(t, ok)
-		assert.Equal(t, &WebSocketEvent{
+		assert.Equal(t, &WebSocketOpEvent{
 			Success: nil,
 			RetMsg:  nil,
 			ConnId:  "civn4p1dcjmtvb69ome0-yrt1",
@@ -80,9 +83,9 @@ func Test_parseWebSocketEvent(t *testing.T) {
 		assert.NoError(t, err)
 
 		expReqId := "78d36b57-a142-47b7-9143-5843df77d44d"
-		e, ok := raw.(*WebSocketEvent)
+		e, ok := raw.(*WebSocketOpEvent)
 		assert.True(t, ok)
-		assert.Equal(t, &WebSocketEvent{
+		assert.Equal(t, &WebSocketOpEvent{
 			Success: nil,
 			RetMsg:  nil,
 			ConnId:  "civn4p1dcjmtvb69ome0-yrt1",
@@ -101,7 +104,7 @@ func Test_WebSocketEventIsValid(t *testing.T) {
 		expRetMsg := string(WsOpTypePong)
 		expReqId := "b26704da-f5af-44c2-bdf7-935d6739e1a0"
 
-		w := &WebSocketEvent{
+		w := &WebSocketOpEvent{
 			Success: &expSucceeds,
 			RetMsg:  &expRetMsg,
 			ReqId:   &expReqId,
@@ -113,7 +116,7 @@ func Test_WebSocketEventIsValid(t *testing.T) {
 	})
 
 	t.Run("[private] valid op ping", func(t *testing.T) {
-		w := &WebSocketEvent{
+		w := &WebSocketOpEvent{
 			Success: nil,
 			RetMsg:  nil,
 			ReqId:   nil,
@@ -129,7 +132,7 @@ func Test_WebSocketEventIsValid(t *testing.T) {
 		expRetMsg := string(WsOpTypePong)
 		expReqId := "b26704da-f5af-44c2-bdf7-935d6739e1a0"
 
-		w := &WebSocketEvent{
+		w := &WebSocketOpEvent{
 			Success: &expSucceeds,
 			RetMsg:  &expRetMsg,
 			ReqId:   &expReqId,
@@ -137,21 +140,21 @@ func Test_WebSocketEventIsValid(t *testing.T) {
 			Op:      WsOpTypePing,
 			Args:    nil,
 		}
-		assert.Error(t, fmt.Errorf("unexpeted response of pong: %#v", w), w.IsValid())
+		assert.Error(t, fmt.Errorf("unexpeted response of pong: %+v", w), w.IsValid())
 	})
 
 	t.Run("[public] missing Success field", func(t *testing.T) {
 		expRetMsg := string(WsOpTypePong)
 		expReqId := "b26704da-f5af-44c2-bdf7-935d6739e1a0"
 
-		w := &WebSocketEvent{
+		w := &WebSocketOpEvent{
 			RetMsg: &expRetMsg,
 			ReqId:  &expReqId,
 			ConnId: "test-conndid",
 			Op:     WsOpTypePing,
 			Args:   nil,
 		}
-		assert.Error(t, fmt.Errorf("unexpeted response of pong: %#v", w), w.IsValid())
+		assert.Error(t, fmt.Errorf("unexpeted response of pong: %+v", w), w.IsValid())
 	})
 
 	t.Run("[public] invalid ret msg", func(t *testing.T) {
@@ -159,7 +162,7 @@ func Test_WebSocketEventIsValid(t *testing.T) {
 		expRetMsg := "PINGPONGPINGPONG"
 		expReqId := "b26704da-f5af-44c2-bdf7-935d6739e1a0"
 
-		w := &WebSocketEvent{
+		w := &WebSocketOpEvent{
 			Success: &expSucceeds,
 			RetMsg:  &expRetMsg,
 			ReqId:   &expReqId,
@@ -167,25 +170,203 @@ func Test_WebSocketEventIsValid(t *testing.T) {
 			Op:      WsOpTypePing,
 			Args:    nil,
 		}
-		assert.Error(t, fmt.Errorf("unexpeted response of pong: %#v", w), w.IsValid())
+		assert.Error(t, fmt.Errorf("unexpeted response of pong: %+v", w), w.IsValid())
 	})
 
 	t.Run("[public] missing RetMsg field", func(t *testing.T) {
 		expReqId := "b26704da-f5af-44c2-bdf7-935d6739e1a0"
 
-		w := &WebSocketEvent{
+		w := &WebSocketOpEvent{
 			ReqId:  &expReqId,
 			ConnId: "test-conndid",
 			Op:     WsOpTypePing,
 			Args:   nil,
 		}
-		assert.Error(t, fmt.Errorf("unexpeted response of pong: %#v", w), w.IsValid())
+		assert.Error(t, fmt.Errorf("unexpeted response of pong: %+v", w), w.IsValid())
 	})
 
 	t.Run("unexpected op type", func(t *testing.T) {
-		w := &WebSocketEvent{
+		w := &WebSocketOpEvent{
 			Op: WsOpType("unexpected"),
 		}
-		assert.Error(t, fmt.Errorf("unexpected op type: %#v", w), w.IsValid())
+		assert.Error(t, fmt.Errorf("unexpected op type: %+v", w), w.IsValid())
+	})
+
+	t.Run("[subscribe] valid", func(t *testing.T) {
+		expSucceeds := true
+		expRetMsg := ""
+		w := &WebSocketOpEvent{
+			Success: &expSucceeds,
+			RetMsg:  &expRetMsg,
+			ReqId:   nil,
+			ConnId:  "test-conndid",
+			Op:      WsOpTypeSubscribe,
+			Args:    nil,
+		}
+		assert.NoError(t, w.IsValid())
+	})
+
+	t.Run("[subscribe] un-succeeds", func(t *testing.T) {
+		expSucceeds := false
+		expRetMsg := ""
+		w := &WebSocketOpEvent{
+			Success: &expSucceeds,
+			RetMsg:  &expRetMsg,
+			ReqId:   nil,
+			ConnId:  "test-conndid",
+			Op:      WsOpTypeSubscribe,
+			Args:    nil,
+		}
+		assert.Error(t, fmt.Errorf("unexpected subscribe result: %+v", w), w.IsValid())
 	})
 }
+
+func TestBookEvent_OrderBook(t *testing.T) {
+	t.Run("snapshot", func(t *testing.T) {
+		/*
+			{
+			   "topic":"orderbook.50.BTCUSDT",
+			   "ts":1691129753071,
+			   "type":"snapshot",
+			   "data":{
+			      "s":"BTCUSDT",
+			      "b":[
+			         [
+			            "29230.81",
+			            "4.713817"
+			         ],
+			         [
+			            "29230",
+			            "0.1646"
+			         ],
+			         [
+			            "29229.92",
+			            "0.036"
+			         ],
+			      ],
+			      "a":[
+			         [
+			            "29230.82",
+			            "2.745421"
+			         ],
+			         [
+			            "29231.41",
+			            "1.6"
+			         ],
+			         [
+			            "29231.42",
+			            "0.513654"
+			         ],
+			      ],
+			      "u":1841364,
+			      "seq":10558648910
+			   }
+			}
+		*/
+		event := &BookEvent{
+			Symbol: "BTCUSDT",
+			Bids: types.PriceVolumeSlice{
+				{
+					fixedpoint.NewFromFloat(29230.81),
+					fixedpoint.NewFromFloat(4.713817),
+				},
+				{
+					fixedpoint.NewFromFloat(29230),
+					fixedpoint.NewFromFloat(0.1646),
+				},
+				{
+					fixedpoint.NewFromFloat(29229.92),
+					fixedpoint.NewFromFloat(0.036),
+				},
+			},
+			Asks: types.PriceVolumeSlice{
+				{
+					fixedpoint.NewFromFloat(29230.82),
+					fixedpoint.NewFromFloat(2.745421),
+				},
+				{
+					fixedpoint.NewFromFloat(29231.41),
+					fixedpoint.NewFromFloat(1.6),
+				},
+				{
+					fixedpoint.NewFromFloat(29231.42),
+					fixedpoint.NewFromFloat(0.513654),
+				},
+			},
+			UpdateId:   fixedpoint.NewFromFloat(1841364),
+			SequenceId: fixedpoint.NewFromFloat(10558648910),
+			Type:       DataTypeSnapshot,
+		}
+
+		expSliceOrderBook := types.SliceOrderBook{
+			Symbol: event.Symbol,
+			Bids:   event.Bids,
+			Asks:   event.Asks,
+		}
+
+		assert.Equal(t, expSliceOrderBook, event.OrderBook())
+	})
+	t.Run("delta", func(t *testing.T) {
+		/*
+			{
+			   "topic":"orderbook.50.BTCUSDT",
+			   "ts":1691130685111,
+			   "type":"delta",
+			   "data":{
+			      "s":"BTCUSDT",
+			      "b":[
+
+			      ],
+			      "a":[
+			         [
+			            "29239.37",
+			            "0.082356"
+			         ],
+			         [
+			            "29236.1",
+			            "0"
+			         ]
+			      ],
+			      "u":1854104,
+			      "seq":10559247733
+			   }
+			}
+		*/
+		event := &BookEvent{
+			Symbol: "BTCUSDT",
+			Bids:   types.PriceVolumeSlice{},
+			Asks: types.PriceVolumeSlice{
+				{
+					fixedpoint.NewFromFloat(29239.37),
+					fixedpoint.NewFromFloat(0.082356),
+				},
+				{
+					fixedpoint.NewFromFloat(29236.1),
+					fixedpoint.NewFromFloat(0),
+				},
+			},
+			UpdateId:   fixedpoint.NewFromFloat(1854104),
+			SequenceId: fixedpoint.NewFromFloat(10559247733),
+			Type:       DataTypeDelta,
+		}
+
+		expSliceOrderBook := types.SliceOrderBook{
+			Symbol: event.Symbol,
+			Bids:   types.PriceVolumeSlice{},
+			Asks:   event.Asks,
+		}
+
+		assert.Equal(t, expSliceOrderBook, event.OrderBook())
+	})
+
+}
+
+func Test_genTopicName(t *testing.T) {
+	exp := "orderbook.50.BTCUSDT"
+	assert.Equal(t, exp, genTopic(TopicTypeOrderBook, types.DepthLevel50, "BTCUSDT"))
+}
+
+func Test_getTopicName(t *testing.T) {
+	exp := TopicTypeOrderBook
+	assert.Equal(t, exp, getTopicType("orderbook.50.BTCUSDT"))
+}

pkg/types/stream.go

@@ -440,6 +440,7 @@ const (
 	DepthLevel1      Depth = "1"
 	DepthLevel5      Depth = "5"
 	DepthLevel20     Depth = "20"
+	DepthLevel50     Depth = "50"
 )
 
 type Speed string