Initial commit

clients/kraken.go

@@ -0,0 +1,138 @@
+package clients
+
+import (
+	"btclock/broker"
+	"btclock/models"
+	"btclock/modules"
+	"context"
+	"log"
+
+	"github.com/coder/websocket"
+	"github.com/coder/websocket/wsjson"
+)
+
+type KrakenClient struct {
+	ws         *websocket.Conn
+	eventTypes []string
+	broker     *broker.EventBroker
+}
+
+type KrakenTickerEvent struct {
+	Symbol string
+	Last   float64
+}
+
+// Name implements broker.Event.
+func (k KrakenTickerEvent) Name() string {
+	return "ticker"
+}
+
+// Payload implements broker.Event.
+func (k KrakenTickerEvent) Payload() interface{} {
+	return map[string]interface{}{
+		"symbol": k.Symbol,
+		"last":   k.Last,
+	}
+}
+
+func init() {
+	modules.Registry.Register(NewKrakenClient())
+}
+
+func NewKrakenClient() *KrakenClient {
+	return &KrakenClient{
+		eventTypes: []string{"ticker"},
+	}
+}
+
+func (k *KrakenClient) Init(broker *broker.EventBroker) error {
+	k.broker = broker
+
+	return nil
+}
+
+func (k *KrakenClient) Start(ctx context.Context) error {
+	ws, _, err := websocket.Dial(ctx, "wss://ws.kraken.com/v2", nil)
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer ws.CloseNow()
+
+	err = wsjson.Write(ctx, ws, map[string]interface{}{
+		"method": "subscribe",
+		"params": map[string]interface{}{
+			"channel": "ticker",
+			"symbol":  []string{"BTC/USD", "BTC/EUR", "BTC/GBP", "BTC/JPY", "BTC/CHF", "BTC/CAD", "BTC/AUD"},
+		},
+	})
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	// Expect subscription confirmation
+	var v map[string]interface{}
+	err = wsjson.Read(ctx, ws, &v)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	// Read messages until the connection is closed
+	for {
+		var v map[string]any
+		err = wsjson.Read(ctx, ws, &v)
+		if err != nil {
+			log.Fatal(err)
+		}
+		channel, ok := v["channel"].(string)
+		if !ok {
+			continue
+		}
+		if channel == "ticker" {
+			tickerData := handleTickerMessage(v)
+			tickerEvent := KrakenTickerEvent{
+				Symbol: tickerData.Symbol,
+				Last:   tickerData.Last,
+			}
+			k.broker.Publish("ticker", tickerEvent)
+		}
+	}
+}
+
+func (k *KrakenClient) Stop() error {
+	k.ws.Close(websocket.StatusNormalClosure, "")
+
+	return nil
+}
+
+func (k *KrakenClient) ID() string {
+	return "kraken"
+}
+
+func handleTickerMessage(v map[string]any) models.Ticker {
+	data, ok := v["data"].([]interface{})
+	if !ok {
+		return models.Ticker{}
+	}
+
+	for _, item := range data {
+		if ticker, ok := item.(map[string]interface{}); ok {
+			symbol, symbolOk := ticker["symbol"].(string)
+			last, lastOk := ticker["last"].(float64)
+			bid, bidOk := ticker["bid"].(float64)
+			ask, askOk := ticker["ask"].(float64)
+
+			if symbolOk && lastOk && bidOk && askOk {
+				ticker := models.Ticker{
+					Symbol: symbol,
+					Last:   last,
+					Bid:    bid,
+					Ask:    ask,
+				}
+				// fmt.Printf("%+v\n", ticker)
+				return ticker
+			}
+		}
+	}
+
+	return models.Ticker{}
+}