package mainimport (  "fmt"  "strconv"  "time"  "math/rand"  "net"  "flag"  "strings"  "encoding/json")// 節點數據信息type NodeInfo struct {  // 節點ID，通過隨機數生成  NodeId int `json:"nodeId"`  // 節點IP地址  NodeIpAddr string `json:"nodeIpAddr"`  // 節點端口  Port string `json: "port"`}// 將節點數據信息格式化輸出//NodeInfo:{nodeId: 89423,nodeIpAddr: 127.0.0.1/8,port: 8001}func (node *NodeInfo) String() string {  return "NodeInfo:{ nodeId:" + strconv.Itoa(node.NodeId) + ",nodeIpAddr:" + node.NodeIpAddr + ",port:" + node.Port + "}"}/* 添加一個節點到集群的一個請求或者響應的標準格式 */type AddToClusterMessage struct {  // 源節點  Source NodeInfo `json:"source"`  // 目的節點  Dest NodeInfo `json:"dest"`  // 兩個節點連接時發送的消息  Message string `json:"message"`}/* Request/Response 信息格式化輸出 */func (req AddToClusterMessage) String() string {  return "AddToClusterMessage:{/n source:" + req.Source.String() + ",/n dest: " + req.Dest.String() + ",/n message:" + req.Message + " }"}// cat vi go// rmfunc main() {  // 解析命令行參數  makeMasterOnError := flag.Bool("makeMasterOnError", false, "如果IP地址沒有連接到集群中，我們將其作為Master節點.")  clusterip := flag.String("clusterip", "127.0.0.1:8001", "任何的節點連接都連接這個IP")  myport := flag.String("myport", "8001", "ip address to run this node on. default is 8001.")  flag.Parse() //解析  fmt.Println(*makeMasterOnError)  fmt.Println(*clusterip)  fmt.Println(*myport)  /* 為節點生成ID */  rand.Seed(time.Now().UTC().UnixNano()) //種子  myid := rand.Intn(99999999) // 隨機  //fmt.Println(myid)  // 獲取IP地址  myIp,_ := net.InterfaceAddrs()  fmt.Println(myIp[0])  // 創建NodeInfo結構體對象  me := NodeInfo{NodeId: myid, NodeIpAddr: myIp[0].String(), Port: *myport}  // 輸出結構體數據信息  fmt.Println(me.String())  dest := NodeInfo{ NodeId: -1, NodeIpAddr: strings.Split(*clusterip, ":")[0], Port: strings.Split(*clusterip, ":")[1]}  /* 嘗試連接到集群，在已連接的情況下并且向集群發送請求 */  ableToConnect := connectToCluster(me, dest)  /*   * 監聽其他節點將要加入到集群的請求   */  if ableToConnect || (!ableToConnect && *makeMasterOnError) {    if *makeMasterOnError {fmt.Println("Will start this node as master.")}    listenOnPort(me)  } else {    fmt.Println("Quitting system. Set makeMasterOnError flag to make the node master.", myid)  }}/* * 這是發送請求時格式化json包有用的工具 * 這是非常重要的，如果不經過數據格式化，你最終發送的將是空白消息 */func getAddToClusterMessage(source NodeInfo, dest NodeInfo, message string) (AddToClusterMessage){  return AddToClusterMessage{    Source: NodeInfo{      NodeId: source.NodeId,      NodeIpAddr: source.NodeIpAddr,      Port: source.Port,    },    Dest: NodeInfo{      NodeId: dest.NodeId,      NodeIpAddr: dest.NodeIpAddr,      Port: dest.Port,    },    Message: message,  }}func connectToCluster(me NodeInfo, dest NodeInfo) (bool){  /* 連接到socket的相關細節信息 */  connOut, err := net.DialTimeout("tcp", dest.NodeIpAddr + ":" + dest.Port, time.Duration(10) * time.Second)  if err != nil {    if _, ok := err.(net.Error); ok {      fmt.Println("未連接到集群.", me.NodeId)      return false    }  } else {    fmt.Println("連接到集群. 發送消息到節點.")    text := "Hi nody.. 請添加我到集群.."    requestMessage := getAddToClusterMessage(me, dest, text)    json.NewEncoder(connOut).Encode(&requestMessage)    decoder := json.NewDecoder(connOut)    var responseMessage AddToClusterMessage    decoder.Decode(&responseMessage)    fmt.Println("得到數據響應:/n" + responseMessage.String())    return true  }  return false}func listenOnPort(me NodeInfo){  /* 監聽即將到來的消息 */  ln, _ := net.Listen("tcp", fmt.Sprint(":" + me.Port))  /* 接受連接 */  for {    connIn, err := ln.Accept()    if err != nil {      if _, ok := err.(net.Error); ok {        fmt.Println("Error received while listening.", me.NodeId)      }    } else {      var requestMessage AddToClusterMessage      json.NewDecoder(connIn).Decode(&requestMessage)      fmt.Println("Got request:/n" + requestMessage.String())      text := "Sure buddy.. too easy.."      responseMessage := getAddToClusterMessage(me, requestMessage.Source, text)      json.NewEncoder(connIn).Encode(&responseMessage)      connIn.Close()    }  }}

/Users/liyuechun/goliyuechun:go yuechunli$ go install mainliyuechun:go yuechunli$ mainMy details: NodeInfo:{ nodeId:53163002, nodeIpAddr:127.0.0.1/8, port:8001 }不能連接到集群. 53163002Quitting system. Set makeMasterOnError flag to make the node master. 53163002liyuechun:go yuechunli$

$ ./bin/main -h

liyuechun:go yuechunli$ ./bin/main -hUsage of ./bin/main: -clusterip string    ip address of any node to connnect (default "127.0.0.1:8001") -makeMasterOnError    make this node master if unable to connect to the cluster ip provided. -myport string    ip address to run this node on. default is 8001. (default "8001")liyuechun:go yuechunli$

$ ./bin/main --makeMasterOnError

liyuechun:go yuechunli$ ./bin/main --makeMasterOnErrorMy details: NodeInfo:{ nodeId:82381143, nodeIpAddr:127.0.0.1/8, port:8001 }未連接到集群. 82381143Will start this node as master.

$ ./bin/main --myport 8002 --clusterip 127.0.0.1:8001

main --myport 8004 --clusterip 127.0.0.1:8001

$ main --myport 8003 --clusterip 127.0.0.1:8002