add debug printer

example/main.go

@@ -34,7 +34,7 @@ func main() {
 	log.Printf("Subscribing to %d markets\n", len(tradingMarkets))
 	<-time.After(time.Second * 2)
 
-	listener := bitvavo.NewTickerListener()
+	listener := bitvavo.NewTickerListener(bitvavo.NewDebugPrinter())
 	defer func() {
 		_ = listener.Close()
 	}()

internal/socket/socket.go

@@ -31,7 +31,7 @@ func NewSocket(
 	}
 
 	socket := &Socket{
-		buffer:        make(chan []byte, 2048),
+		buffer:        make(chan []byte, 1024),
 		conn:          conn,
 		url:           url,
 		handleFunc:    handleFunc,

pkg/bitvavo/debug_printer.go

@@ -0,0 +1,26 @@
+package bitvavo
+
+import (
+	"fmt"
+	"log"
+)
+
+type DebugPrinter interface {
+	Println(value ...any)
+}
+
+type DefaultDebugPrinter struct{}
+
+func NewDebugPrinter() *DefaultDebugPrinter {
+	return &DefaultDebugPrinter{}
+}
+
+func (l *DefaultDebugPrinter) Println(value ...any) {
+	log.Println(value...)
+}
+
+func debug(p DebugPrinter, value ...any) {
+	if p != nil {
+		p.Println(fmt.Sprintf("[BITVAVO-GO] %v", value...))
+	}
+}

pkg/bitvavo/listener.go

@@ -45,6 +45,7 @@ type listener[T any] struct {
 	channel       Channel
 	subscriptions []Subscription
 	closefn       context.CancelFunc
+	printer       DebugPrinter
 }
 
 type authListener[T any] struct {

pkg/bitvavo/ticker_listener.go

@@ -9,7 +9,7 @@ type TickerEvent ListenerEvent[Ticker]
 
 type TickerListener listener[TickerEvent]
 
-func NewTickerListener() Listener[TickerEvent] {
+func NewTickerListener(printer ...DebugPrinter) Listener[TickerEvent] {
 	chn := make(chan TickerEvent)
 	rchn := make(chan struct{})
 
@@ -20,6 +20,10 @@ func NewTickerListener() Listener[TickerEvent] {
 		channel: ChannelTicker,
 	}
 
+	if len(printer) > 0 {
+		l.printer = printer[0]
+	}
+
 	ctx, cancel := context.WithCancel(context.Background())
 	ws, err := NewWebSocket(ctx, l.onMessage, func() {
 		rchn <- struct{}{}
@@ -36,6 +40,8 @@ func NewTickerListener() Listener[TickerEvent] {
 }
 
 func (l *TickerListener) Subscribe(markets []string) (<-chan TickerEvent, error) {
+	debug(l.printer, "subscribing to", markets)
+
 	if err := l.ws.Subscribe([]Subscription{NewSubscription(l.channel, markets)}); err != nil {
 		return nil, err
 	}
@@ -90,11 +96,11 @@ func (l *TickerListener) onMessage(data WebSocketEventData, err error) {
 	}
 }
 
-func (t *TickerListener) resubscriber() {
-	t.once.Do(func() {
-		for range t.rchn {
-			if err := t.ws.Subscribe(t.subscriptions); err != nil {
-				t.chn <- TickerEvent{Error: err}
+func (l *TickerListener) resubscriber() {
+	l.once.Do(func() {
+		for range l.rchn {
+			if err := l.ws.Subscribe(l.subscriptions); err != nil {
+				l.chn <- TickerEvent{Error: err}
 			}
 		}
 	})