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Java转Go日记（三十六）：简单的分布式

news 2025/5/16 7:46:17

1.1.1. 简单的分布式server

目前分布式系统已经很流行了，一些开源框架也被广泛应用，如dubbo、Motan等。对于一个分布式服务，最基本的一项功能就是服务的注册和发现，而利用zk的EPHEMERAL节点则可以很方便的实现该功能。EPHEMERAL节点正如其名，是临时性的，其生命周期是和客户端会话绑定的，当会话连接断开时，节点也会被删除。下边我们就来实现一个简单的分布式server：

server：

服务启动时，创建zk连接，并在go_servers节点下创建一个新节点，节点名为"ip:port"，完成服务注册服务结束时，由于连接断开，创建的节点会被删除，这样client就不会连到该节点

client：

先从zk获取go_servers节点下所有子节点，这样就拿到了所有注册的server 从server列表中选中一个节点（这里只是随机选取，实际服务一般会提供多种策略），创建连接进行通信这里为了演示，我们每次client连接server，获取server发送的时间后就断开。主要代码如下：

server.go

package mainimport ("fmt""net""os""time""github.com/samuel/go-zookeeper/zk"
)func main() {go starServer("127.0.0.1:8897")go starServer("127.0.0.1:8898")go starServer("127.0.0.1:8899")a := make(chan bool, 1)<-a
}func checkError(err error) {if err != nil {fmt.Println(err)}
}func starServer(port string) {tcpAddr, err := net.ResolveTCPAddr("tcp4", port)fmt.Println(tcpAddr)checkError(err)listener, err := net.ListenTCP("tcp", tcpAddr)checkError(err)//注册zk节点q// 链接zkconn, err := GetConnect()if err != nil {fmt.Printf(" connect zk error: %s ", err)}defer conn.Close()// zk节点注册err = RegistServer(conn, port)if err != nil {fmt.Printf(" regist node error: %s ", err)}for {conn, err := listener.Accept()if err != nil {fmt.Fprintf(os.Stderr, "Error: %s", err)continue}go handleCient(conn, port)}fmt.Println("aaaaaa")
}func handleCient(conn net.Conn, port string) {defer conn.Close()daytime := time.Now().String()conn.Write([]byte(port + ": " + daytime))
}
func GetConnect() (conn *zk.Conn, err error) {zkList := []string{"localhost:2181"}conn, _, err = zk.Connect(zkList, 10*time.Second)if err != nil {fmt.Println(err)}return
}func RegistServer(conn *zk.Conn, host string) (err error) {_, err = conn.Create("/go_servers/"+host, nil, zk.FlagEphemeral, zk.WorldACL(zk.PermAll))return
}func GetServerList(conn *zk.Conn) (list []string, err error) {list, _, err = conn.Children("/go_servers")return
}

1.1.2. client.go

package mainimport ("errors""fmt""io/ioutil""math/rand""net""time""github.com/samuel/go-zookeeper/zk"
)func checkError(err error) {if err != nil {fmt.Println(err)}
}
func main() {for i := 0; i < 100; i++ {startClient()time.Sleep(1 * time.Second)}
}func startClient() {// service := "127.0.0.1:8899"//获取地址serverHost, err := getServerHost()if err != nil {fmt.Printf("get server host fail: %s \n", err)return}fmt.Println("connect host: " + serverHost)tcpAddr, err := net.ResolveTCPAddr("tcp4", serverHost)checkError(err)conn, err := net.DialTCP("tcp", nil, tcpAddr)checkError(err)defer conn.Close()_, err = conn.Write([]byte("timestamp"))checkError(err)result, err := ioutil.ReadAll(conn)checkError(err)fmt.Println(string(result))return
}func getServerHost() (host string, err error) {conn, err := GetConnect()if err != nil {fmt.Printf(" connect zk error: %s \n ", err)return}defer conn.Close()serverList, err := GetServerList(conn)if err != nil {fmt.Printf(" get server list error: %s \n", err)return}count := len(serverList)if count == 0 {err = errors.New("server list is empty \n")return}//随机选中一个返回r := rand.New(rand.NewSource(time.Now().UnixNano()))host = serverList[r.Intn(3)]return
}
func GetConnect() (conn *zk.Conn, err error) {zkList := []string{"localhost:2181"}conn, _, err = zk.Connect(zkList, 10*time.Second)if err != nil {fmt.Println(err)}return
}
func GetServerList(conn *zk.Conn) (list []string, err error) {list, _, err = conn.Children("/go_servers")return
}

先启动server，可以看到有三个节点注册到zk：

    127.0.0.1:8897127.0.0.1:8899127.0.0.1:88982018/08/27 14:04:58 Connected to 127.0.0.1:21812018/08/27 14:04:58 Connected to 127.0.0.1:21812018/08/27 14:04:58 Connected to 127.0.0.1:21812018/08/27 14:04:58 Authenticated: id=100619932030205976, timeout=100002018/08/27 14:04:58 Re-submitting `0` credentials after reconnect2018/08/27 14:04:58 Authenticated: id=100619932030205977, timeout=100002018/08/27 14:04:58 Re-submitting `0` credentials after reconnect2018/08/27 14:04:58 Authenticated: id=100619932030205978, timeout=100002018/08/27 14:04:58 Re-submitting `0` credentials after reconnect

启动client，可以看到每次client都会随机连接到一个节点进行通信：

    2018/08/27 14:05:21 Connected to 127.0.0.1:21812018/08/27 14:05:21 Authenticated: id=100619932030205979, timeout=100002018/08/27 14:05:21 Re-submitting `0` credentials after reconnect2018/08/27 14:05:21 Recv loop terminated: err=EOFconnect host: 127.0.0.1:88992018/08/27 14:05:21 Send loop terminated: err=<nil>read tcp 127.0.0.1:54062->127.0.0.1:8899: read: connection reset by peer127.0.0.1:8899: 2018-08-27 14:05:21.291641 +0800 CST m=+22.4801496562018/08/27 14:05:22 Connected to [::1]:21812018/08/27 14:05:22 Authenticated: id=100619932030205980, timeout=100002018/08/27 14:05:22 Re-submitting `0` credentials after reconnect2018/08/27 14:05:22 Recv loop terminated: err=EOF2018/08/27 14:05:22 Send loop terminated: err=<nil>connect host: 127.0.0.1:8897read tcp 127.0.0.1:54064->127.0.0.1:8897: read: connection reset by peer127.0.0.1:8897: 2018-08-27 14:05:22.302322 +0800 CST m=+23.4908013852018/08/27 14:05:23 Connected to 127.0.0.1:21812018/08/27 14:05:23 Authenticated: id=100619932030205981, timeout=100002018/08/27 14:05:23 Re-submitting `0` credentials after reconnect2018/08/27 14:05:23 Recv loop terminated: err=EOF2018/08/27 14:05:23 Send loop terminated: err=<nil>connect host: 127.0.0.1:8897read tcp 127.0.0.1:54070->127.0.0.1:8897: read: connection reset by peer127.0.0.1:8897: 2018-08-27 14:05:23.312873 +0800 CST m=+24.5013242282018/08/27 14:05:24 Connected to 127.0.0.1:21812018/08/27 14:05:24 Authenticated: id=100619932030205982, timeout=100002018/08/27 14:05:24 Re-submitting `0` credentials after reconnect2018/08/27 14:05:24 Recv loop terminated: err=EOFconnect host: 127.0.0.1:88992018/08/27 14:05:24 Send loop terminated: err=<nil>read tcp 127.0.0.1:54072->127.0.0.1:8899: read: connection reset by peer127.0.0.1:8899: 2018-08-27 14:05:24.323668 +0800 CST m=+25.5120901552018/08/27 14:05:25 Connected to 127.0.0.1:21812018/08/27 14:05:25 Authenticated: id=100619932030205983, timeout=100002018/08/27 14:05:25 Re-submitting `0` credentials after reconnect2018/08/27 14:05:25 Recv loop terminated: err=EOF2018/08/27 14:05:25 Send loop terminated: err=<nil>connect host: 127.0.0.1:8897read tcp 127.0.0.1:54074->127.0.0.1:8897: read: connection reset by peer127.0.0.1:8897: 2018-08-27 14:05:25.330257 +0800 CST m=+26.5186505662018/08/27 14:05:26 Connected to [::1]:21812018/08/27 14:05:26 Authenticated: id=100619932030205984, timeout=100002018/08/27 14:05:26 Re-submitting `0` credentials after reconnect2018/08/27 14:05:26 Recv loop terminated: err=EOF2018/08/27 14:05:26 Send loop terminated: err=<nil>connect host: 127.0.0.1:8897read tcp 127.0.0.1:54080->127.0.0.1:8897: read: connection reset by peer127.0.0.1:8897: 2018-08-27 14:05:26.357251 +0800 CST m=+27.5456146162018/08/27 14:05:27 Connected to 127.0.0.1:21812018/08/27 14:05:27 Authenticated: id=100619932030205985, timeout=100002018/08/27 14:05:27 Re-submitting `0` credentials after reconnectconnect host: 127.0.0.1:88992018/08/27 14:05:27 Recv loop terminated: err=EOF2018/08/27 14:05:27 Send loop terminated: err=<nil>read tcp 127.0.0.1:54082->127.0.0.1:8899: read: connection reset by peer127.0.0.1:8899: 2018-08-27 14:05:27.369096 +0800 CST m=+28.5574307642018/08/27 14:05:28 Connected to [::1]:21812018/08/27 14:05:28 Authenticated: id=100619932030205986, timeout=100002018/08/27 14:05:28 Re-submitting `0` credentials after reconnect2018/08/27 14:05:28 Recv loop terminated: err=EOF2018/08/27 14:05:28 Send loop terminated: err=<nil>connect host: 127.0.0.1:8898read tcp 127.0.0.1:54084->127.0.0.1:8898: read: connection reset by peer127.0.0.1:8898: 2018-08-27 14:05:28.380455 +0800 CST m=+29.568760988......

至此，我们的分布式server就实现了

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