feat: The abstract log interface facilitates external access to logs.

config.go

@@ -6,7 +6,6 @@ package memberlist
 import (
 	"fmt"
 	"io"
-	"log"
 	"net"
 	"os"
 	"strings"
@@ -224,7 +223,7 @@ type Config struct {
 	// this for the internal logger. If Logger is not set, it will fall back to the
 	// behavior for using LogOutput. You cannot specify both LogOutput and Logger
 	// at the same time.
-	Logger *log.Logger
+	Logger Logger
 
 	// Size of Memberlist's internal channel which handles UDP messages. The
 	// size of this determines the size of the queue which Memberlist will keep

logging.go

@@ -8,6 +8,10 @@ import (
 	"net"
 )
 
+type Logger interface {
+	Printf(format string, v ...interface{})
+}
+
 func LogAddress(addr net.Addr) string {
 	if addr == nil {
 		return "from=<unknown address>"

memberlist.go

@@ -80,7 +80,7 @@ type Memberlist struct {
 
 	broadcasts *TransmitLimitedQueue
 
-	logger *log.Logger
+	logger Logger
 
 	// metricLabels is the slice of labels to put on all emitted metrics
 	metricLabels []metrics.Label

net_transport.go

@@ -7,7 +7,6 @@ import (
 	"bytes"
 	"fmt"
 	"io"
-	"log"
 	"net"
 	"sync"
 	"sync/atomic"
@@ -37,7 +36,7 @@ type NetTransportConfig struct {
 	BindPort int
 
 	// Logger is a logger for operator messages.
-	Logger *log.Logger
+	Logger Logger
 
 	// MetricLabels is a map of optional labels to apply to all metrics
 	// emitted by this transport.
@@ -50,7 +49,7 @@ type NetTransport struct {
 	config       *NetTransportConfig
 	packetCh     chan *Packet
 	streamCh     chan net.Conn
-	logger       *log.Logger
+	logger       Logger
 	wg           sync.WaitGroup
 	tcpListeners []*net.TCPListener
 	udpListeners []*net.UDPConn