[Question]: How to shut down the started tcp server and turn off port listening?

[shiyuecamus]

Actions I've taken before I'm here

• I've thoroughly read the documentations about this problem but still have no answer.
• I've searched the Github Issues/Discussions but didn't find any similar problems that have been solved.
• I've searched the internet for this problem but didn't find anything helpful.

Questions with details

调用eng.Stop(context.Background())后端口依然被占用。请问如何解决？一下是我的完整版代码

Code snippets (optional)

package initializer

import (
	"context"
	"encoding/json"
	"fmt"
	"github.com/panjf2000/gnet/v2"
	"github.com/sirupsen/logrus"
	"time"
)

type Discoverer struct {
	ts        tcpServer
	us        udpServer
	onInitReq func(params initParams) error
}

func NewDiscoverer() *Discoverer {
	d := &Discoverer{}
	d.ts = tcpServer{
		onMessage: d.onTcpMessage,
	}
	d.us = udpServer{
		onMessage: d.onUdpMessage,
	}
	return d
}

func (d *Discoverer) comeToLight() (err error) {
	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
	defer cancel()

	var (
		tcpDone = make(chan bool, 1)
		tcpFlag bool
		udpFlag bool
		udpDone = make(chan bool, 1)
		errCh   = make(chan error)
	)

	go func() {
		time.AfterFunc(time.Second*2, func() {
			tcpDone <- true
		})
		if e := gnet.Run(d.ts, "tcp://:12345",
			gnet.WithMulticore(true),
			gnet.WithReuseAddr(true),
			gnet.WithReusePort(true)); e != nil {
			errCh <- fmt.Errorf("discover tcp server run failed with error: %s", e)
			return
		}
	}()

	go func() {
		time.AfterFunc(time.Second*2, func() {
			udpDone <- true
		})
		if e := gnet.Run(d.us, "udp://:54321", gnet.WithMulticore(true),
			gnet.WithReuseAddr(true),
			gnet.WithReusePort(true)); e != nil {
			errCh <- fmt.Errorf("discover udp server run failed with error: %s", e)
		}
	}()

	for {
		if tcpFlag && udpFlag {
			return
		}
		select {
		case tcpFlag = <-tcpDone:
		case udpFlag = <-udpDone:
		case err = <-errCh:
			return
		case <-ctx.Done():
			return fmt.Errorf("server run operation timed out: %s", ctx.Err())
		}
	}
}

func (d *Discoverer) hide() {
	logrus.Info("Gateway Discoverer to hide.")
	d.ts.close()
	d.us.close()
}

type initParams struct {
	DeviceName            string `json:"deviceName"`
	Host                  string `json:"host"`
	Port                  int    `json:"port"`
	ProvisionType         string `json:"provisionType"`
	ProvisionDeviceKey    string `json:"provisionDeviceKey"`
	ProvisionDeviceSecret string `json:"provisionDeviceSecret"`
}

func (d *Discoverer) onTcpMessage(payload []byte, c gnet.Conn) {
	params := initParams{}
	m := map[string]any{
		"code": 1,
	}
	if err := json.Unmarshal(payload, &params); err != nil {
		logrus.Warnf("Gateway discoverer unmarshal json for tcp init request failed with err: %s", err)
		m["code"] = 0
		m["msg"] = fmt.Sprintf("Gateway discoverer unmarshal json for init request failed with err: %s", err)
		goto response
	}
	if d.onInitReq != nil {
		if err := d.onInitReq(params); err != nil {
			m["code"] = 0
			m["msg"] = fmt.Sprintf("Gateway discoverer handler init failed with err: %s", err)
		}
	}
response:
	bytes, _ := json.Marshal(&m)
	_, _ = c.Write(bytes)
}

func (d *Discoverer) onUdpMessage(_ []byte, c gnet.Conn) {
	bs, err := json.Marshal(map[string]any{
		"model": "yunqi.gateway.tb1",
	})
	if err != nil {
		logrus.Warnf("Gateway discoverer marshal json for udp reponse failed with err: %s", err)
	}
	_, err = c.Write(bs)
	if err != nil {
		logrus.Warnf("Gateway discoverer write udp reponse failed with err: %s", err)
	}
}

type tcpServer struct {
	*gnet.BuiltinEventEngine
	eng       gnet.Engine
	onMessage func([]byte, gnet.Conn)
}

type udpServer struct {
	*gnet.BuiltinEventEngine
	eng       gnet.Engine
	onMessage func([]byte, gnet.Conn)
}

func (t tcpServer) OnBoot(eng gnet.Engine) (action gnet.Action) {
	t.eng = eng
	logrus.Infof("Discoverer tcp server is boot")
	return
}

func (t tcpServer) OnShutdown(gnet.Engine) {
	logrus.Infof("Discoverer tcp server is shutdown")
	return
}

func (t tcpServer) OnOpen(c gnet.Conn) (out []byte, action gnet.Action) {
	logrus.Infof("Discoverer tcp client is open for: %s", c.RemoteAddr())
	return
}

func (t tcpServer) OnClose(c gnet.Conn, err error) (action gnet.Action) {
	logrus.Infof("Discoverer tcp client is close for: %s, error: %s", c.Close(), err)
	return
}

func (t tcpServer) OnTraffic(c gnet.Conn) (action gnet.Action) {
	bytes, _ := c.Next(-1)
	pkg := make([]byte, len(bytes))
	copy(pkg, bytes)
	if t.onMessage != nil {
		t.onMessage(bytes, c)
	}
	logrus.Debugf("Discoverer tcp server message: %s, length: %d", c.RemoteAddr().String(), len(pkg))
	return
}

func (t tcpServer) close() {
	_ = t.eng.Stop(context.Background())
}

func (u udpServer) OnBoot(eng gnet.Engine) (action gnet.Action) {
	u.eng = eng
	logrus.Infof("Discoverer udp server is boot")
	return
}

func (u udpServer) OnShutdown(gnet.Engine) {
	logrus.Infof("Discoverer udp server is shutdown")
	return
}

func (u udpServer) OnOpen(c gnet.Conn) (out []byte, action gnet.Action) {
	logrus.Infof("Discoverer udp client is open for: %s", c.RemoteAddr())
	return
}

func (u udpServer) OnClose(c gnet.Conn, err error) (action gnet.Action) {
	logrus.Infof("Discoverer udp client is close for: %s, error: %s", c.Close(), err)
	return
}

func (u udpServer) OnTraffic(c gnet.Conn) (action gnet.Action) {
	bytes, _ := c.Next(-1)
	pkg := make([]byte, len(bytes))
	copy(pkg, bytes)
	logrus.Debugf("Discoverer udp server message: %s, length: %d", c.RemoteAddr().String(), len(pkg))
	if u.onMessage != nil {
		u.onMessage(bytes, c)
	}
	return
}

func (u udpServer) close() {
	_ = u.eng.Stop(context.Background())
}

[panjf2000]

关闭之后有等待 2*MSL 时间之后再重新启动绑定地址吗？否则的话处于 TIME_WAIT 状态的连接无法重新绑定，除非使用 SO_REUSEADDR.

[gh-translator]

🤖 Non-English text detected, translating...

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After shutting down, do you have to wait 2*MSL time before restarting the binding address? Otherwise a connection in TIME_WAIT state cannot be rebound unless SO_REUSEADDR is used.