Update example

examples/socket/unix_domain_socket/abstract-namespace/use-net-conn/README.md

@@ -16,15 +16,17 @@ task: [build] go build -o app main.go
 task: [run] ./app -server &
 task: [run] sleep 1
 task: [run] ./app
-01:59:18.896796 [C] Send (hello)
-01:59:18.896882 [S] Recv (hello)
-01:59:18.897098 [S] Send (HELLO)
-01:59:18.897149 [C] Recv (HELLO)
-01:59:18.897174 [C] close
-01:59:18.897177 [S] disconnect
-01:59:18.897205 [S] close
+02:42:06.032066 [C] Send (hello)
+02:42:06.032128 [S] Recv (hello)
+02:42:06.032345 [S] Send (HELLO)
+02:42:06.032365 [C] Recv (HELLO)
+02:42:06.032378 [C] SEND FIN (shutdown(SHUT_WR))
+02:42:06.032382 [S] disconnect
+02:42:06.032410 [S] close
+02:42:06.032413 [C] disconnect
+02:42:06.032436 [C] close
 task: [run] pkill -INT -f './app -server'
-01:59:18.909751 [S] Shutdown...
+02:42:06.043557 [S] Shutdown...
 ```
 
 ## 参考情報

examples/socket/unix_domain_socket/abstract-namespace/use-net-conn/main.go

@@ -13,6 +13,7 @@ import (
 	"net"
 	"os"
 	"os/signal"
+	"time"
 )
 
 type (
@@ -117,26 +118,29 @@ func runServer() error {
 			}
 			log.Printf("[S] Send (%s)", message)
 
-			// Graceful shutdown
-			{
-				unixConn, ok := conn.(*net.UnixConn)
-				if !ok {
-					errCh <- fmt.Errorf("conn.(*net.UnixConn) failed")
-					return
-				}
+			// FIN待機用のタイムアウト設定
+			err = conn.SetReadDeadline(time.Now().Add(2 * time.Second))
+			if err != nil {
+				log.Printf("[S] SetReadDeadline error: %v", err)
+				errCh <- err
+				return
+			}
 
-				err = unixConn.CloseWrite()
-				if err != nil {
-					errCh <- err
-					return
+			for {
+				clear(buf)
+				if n, err = conn.Read(buf); n == 0 || errors.Is(err, io.EOF) {
+					log.Println("[S] disconnect")
+					break
 				}
 
-				for {
-					clear(buf)
-					if n, err = conn.Read(buf); n == 0 || errors.Is(err, io.EOF) {
-						log.Println("[S] disconnect")
+				if err != nil {
+					if netErr, ok := err.(net.Error); ok && netErr.Timeout() {
+						log.Println("[S] timeout (client FIN)")
 						break
 					}
+
+					errCh <- err
+					return
 				}
 			}
 		}()
@@ -180,5 +184,28 @@ func runClient() error {
 	message := string(buf[:n])
 	log.Printf("[C] Recv (%s)", message)
 
+	// Graceful shutdown
+	{
+		unixConn, ok := conn.(*net.UnixConn)
+		if !ok {
+			return fmt.Errorf("conn.(*net.UnixConn) failed")
+
+		}
+
+		err = unixConn.CloseWrite()
+		if err != nil {
+			return err
+		}
+		log.Println("[C] SEND FIN (shutdown(SHUT_WR))")
+
+		for {
+			clear(buf)
+			if n, err = conn.Read(buf); n == 0 || errors.Is(err, io.EOF) {
+				log.Println("[C] disconnect")
+				break
+			}
+		}
+	}
+
 	return nil
 }