feat: wire default discard connection logger to protocol configuration

Signed-off-by: Chris Gianelloni <wolf31o2@blinklabs.io>

connection.go

@@ -102,6 +102,10 @@ func NewConnection(options ...ConnectionOptionFunc) (*Connection, error) {
 		protoErrorChan:        make(chan error, 10),
 		handshakeFinishedChan: make(chan interface{}),
 		doneChan:              make(chan interface{}),
+		// Create a discard logger to throw away logs. We do this so
+		// we don't have to add guards around every log operation if
+		// a logger is not configured by the user.
+		logger: slog.New(slog.NewJSONHandler(io.Discard, nil)),
 	}
 	// Apply provided options functions
 	for _, option := range options {
@@ -287,6 +291,7 @@ func (c *Connection) setupConnection() error {
 	protoOptions := protocol.ProtocolOptions{
 		ConnectionId: c.id,
 		Muxer:        c.muxer,
+		Logger:       c.logger,
 		ErrorChan:    c.protoErrorChan,
 	}
 	if c.useNodeToNodeProto {

protocol/protocol.go

@@ -1,4 +1,4 @@
-// Copyright 2023 Blink Labs Software
+// Copyright 2024 Blink Labs Software
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -19,6 +19,7 @@ import (
 	"bytes"
 	"fmt"
 	"io"
+	"log/slog"
 	"sync"
 	"time"
 
@@ -53,6 +54,7 @@ type ProtocolConfig struct {
 	ProtocolId          uint16
 	ErrorChan           chan error
 	Muxer               *muxer.Muxer
+	Logger              *slog.Logger
 	Mode                ProtocolMode
 	Role                ProtocolRole
 	MessageHandlerFunc  MessageHandlerFunc
@@ -85,6 +87,7 @@ const (
 type ProtocolOptions struct {
 	ConnectionId connection.ConnectionId
 	Muxer        *muxer.Muxer
+	Logger       *slog.Logger
 	ErrorChan    chan error
 	Mode         ProtocolMode
 	// TODO: remove me
@@ -118,6 +121,7 @@ func New(config ProtocolConfig) *Protocol {
 func (p *Protocol) Start() {
 	p.onceStart.Do(func() {
 		// Register protocol with muxer
+		p.Logger().Debug("registering protocol with muxer")
 		muxerProtocolRole := muxer.ProtocolRoleInitiator
 		if p.config.Role == ProtocolRoleServer {
 			muxerProtocolRole = muxer.ProtocolRoleResponder
@@ -156,6 +160,7 @@ func (p *Protocol) Start() {
 func (p *Protocol) Stop() {
 	p.onceStop.Do(func() {
 		// Unregister protocol from muxer
+		p.Logger().Debug("unregistering protocol with muxer")
 		muxerProtocolRole := muxer.ProtocolRoleInitiator
 		if p.config.Role == ProtocolRoleServer {
 			muxerProtocolRole = muxer.ProtocolRoleResponder
@@ -167,6 +172,14 @@ func (p *Protocol) Stop() {
 	})
 }
 
+// Logger returns the protocol logger
+func (p *Protocol) Logger() *slog.Logger {
+	if p.config.Logger == nil {
+		return slog.New(slog.NewJSONHandler(io.Discard, nil))
+	}
+	return p.config.Logger
+}
+
 // Mode returns the protocol mode
 func (p *Protocol) Mode() ProtocolMode {
 	return p.config.Mode