use context to graceful shutdown

main.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"context"
 	"flag"
 	"fmt"
 	"io"
@@ -10,6 +11,7 @@ import (
 	"os/signal"
 	"strings"
 	"syscall"
+	"time"
 
 	glog "github.com/fangdingjun/go-log"
 	proxyproto "github.com/pires/go-proxyproto"
@@ -59,7 +61,7 @@ func getSNIServerName(buf []byte) string {
 	return msg.serverName
 }
 
-func forward(c net.Conn, data []byte, dst string) {
+func forward(ctx context.Context, c net.Conn, data []byte, dst string) {
 	addr := dst
 	proxyProto := 0
 
@@ -90,8 +92,8 @@ func forward(c net.Conn, data []byte, dst string) {
 			hdr.Version = 2
 		}
 	}
-
+	dialer := &net.Dialer{Timeout: 10 * time.Second}
-	c1, err := net.Dial("tcp", addr)
+	c1, err := dialer.DialContext(ctx, "tcp", addr)
 	if err != nil {
 		glog.Error(err)
 		return
@@ -101,7 +103,10 @@ func forward(c net.Conn, data []byte, dst string) {
 
 	if proxyProto != 0 {
 		glog.Debugf("send proxy proto v%d to %s", proxyProto, addr)
-		hdr.WriteTo(c1)
+		if _, err = hdr.WriteTo(c1); err != nil {
+			glog.Errorln(err)
+			return
+		}
 	}
 
 	if _, err = c1.Write(data); err != nil {
@@ -121,7 +126,10 @@ func forward(c net.Conn, data []byte, dst string) {
 		ch <- struct{}{}
 	}()
 
-	<-ch
+	select {
+	case <-ch:
+	case <-ctx.Done():
+	}
 }
 
 func getDST(c net.Conn, name string) string {
@@ -134,7 +142,7 @@ func getDefaultDST() string {
 	return cfg.Default
 }
 
-func serve(c net.Conn) {
+func serve(ctx context.Context, c net.Conn) {
 	defer c.Close()
 
 	buf := make([]byte, 1024)
@@ -146,7 +154,7 @@ func serve(c net.Conn) {
 	servername := getSNIServerName(buf[:n])
 	if servername == "" {
 		glog.Debugf("no sni, send to default")
-		forward(c, buf[:n], getDefaultDST())
+		forward(ctx, c, buf[:n], getDefaultDST())
 		return
 	}
 	dst := getDST(c, servername)
@@ -154,7 +162,7 @@ func serve(c net.Conn) {
 		dst = getDefaultDST()
 		glog.Debugf("use default dst %s for sni %s", dst, servername)
 	}
-	forward(c, buf[:n], dst)
+	forward(ctx, c, buf[:n], dst)
 }
 
 var cfg conf
@@ -188,28 +196,34 @@ func main() {
 		glog.Default.Level = lv
 	}
 
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
 	for _, d := range cfg.Listen {
 		glog.Infof("listen on :%d", d)
-		l, err := net.Listen("tcp", fmt.Sprintf(":%d", d))
+		lc := &net.ListenConfig{}
+		l, err := lc.Listen(ctx, "tcp", fmt.Sprintf(":%d", d))
 		if err != nil {
 			glog.Fatal(err)
 		}
-		go func(l net.Listener) {
+		go func(ctx context.Context, l net.Listener) {
 			defer l.Close()
 			for {
 				c1, err := l.Accept()
 				if err != nil {
-					glog.Fatal(err)
+					glog.Error(err)
+					break
 				}
-				go serve(c1)
+				go serve(ctx, c1)
 			}
-		}(l)
+		}(ctx, l)
 	}
 
 	ch := make(chan os.Signal, 2)
 	signal.Notify(ch, syscall.SIGINT, syscall.SIGTERM)
 	select {
 	case s := <-ch:
+		cancel()
 		glog.Printf("received signal %s, exit.", s)
 	}
 }

proto_test.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"context"
 	"crypto/tls"
 	"io/ioutil"
 	"net"
@@ -36,7 +37,7 @@ func TestProxyProto(t *testing.T) {
 				log.Errorln(err)
 				return
 			}
-			go serve(conn)
+			go serve(context.Background(), conn)
 		}
 	}()
 	cert, err := tls.LoadX509KeyPair("server.crt", "server.key")