功能
- 能够发送/接收请求和响应
- 能够连接到集群
- 如果无法连接到群集(如果它是第一个节点),则可以作为主节点启动节点
- 每个节点有唯一的标识
- 能够在节点之间交换json数据包
- 接受命令行参数中的所有信息(将来在我们系统升级时将会很有用)
源码
package main
import (
"fmt"
"strconv"
"time"
"math/rand"
"net"
"flag"
"strings"
"encoding/json"
)
// 节点数据信息
type NodeInfo struct {
// 节点ID,通过随机数生成
NodeId int `json:"nodeId"`
// 节点IP地址
NodeIpAddr string `json:"nodeIpAddr"`
// 节点端口
Port string `json: "port"`
}
// 将节点数据信息格式化输出
//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 + "}"
}
/* 添加一个节点到集群的一个请求或者响应的标准格式 */
type AddToClusterMessage struct {
// 源节点
Source NodeInfo `json:"source"`
// 目的节点
Dest NodeInfo `json:"dest"`
// 两个节点连接时发送的消息
Message string `json:"message"`
}
/* Request/Response 信息格式化输出 */
func (req AddToClusterMessage) String() string {
return "AddToClusterMessage:{\n source:" + req.Source.String() + ",\n dest: " + req.Dest.String() + ",\n message:" + req.Message + " }"
}
// cat vi go
// rm
func main() {
// 解析命令行参数
makeMasterOnError := flag.Bool("makeMasterOnError", false, "如果IP地址没有连接到集群中,我们将其作为Master节点.")
clusterip := flag.String("clusterip", "127.0.0.1:8001", "任何的节点连接都连接这个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)
/* 为节点生成ID */
rand.Seed(time.Now().UTC().UnixNano()) //种子
myid := rand.Intn(99999999) // 随机
//fmt.Println(myid)
// 获取IP地址
myIp,_ := net.InterfaceAddrs()
fmt.Println(myIp[0])
// 创建NodeInfo结构体对象
me := NodeInfo{NodeId: myid, NodeIpAddr: myIp[0].String(), Port: *myport}
// 输出结构体数据信息
fmt.Println(me.String())
dest := NodeInfo{ NodeId: -1, NodeIpAddr: strings.Split(*clusterip, ":")[0], Port: strings.Split(*clusterip, ":")[1]}
/* 尝试连接到集群,在已连接的情况下并且向集群发送请求 */
ableToConnect := connectToCluster(me, dest)
/*
* 监听其他节点将要加入到集群的请求
*/
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)
}
}
/*
* 这是发送请求时格式化json包有用的工具
* 这是非常重要的,如果不经过数据格式化,你最终发送的将是空白消息
*/
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){
/* 连接到socket的相关细节信息 */
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("未连接到集群.", me.NodeId)
return false
}
} else {
fmt.Println("连接到集群. 发送消息到节点.")
text := "Hi nody.. 请添加我到集群.."
requestMessage := getAddToClusterMessage(me, dest, text)
json.NewEncoder(connOut).Encode(&requestMessage)
decoder := json.NewDecoder(connOut)
var responseMessage AddToClusterMessage
decoder.Decode(&responseMessage)
fmt.Println("得到数据响应:\n" + responseMessage.String())
return true
}
return false
}
func listenOnPort(me NodeInfo){
/* 监听即将到来的消息 */
ln, _ := net.Listen("tcp", fmt.Sprint(":" + me.Port))
/* 接受连接 */
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()
}
}
}
运行程序
/Users/liyuechun/go
liyuechun:go yuechunli$ go install main
liyuechun:go yuechunli$ main
My details: NodeInfo:{ nodeId:53163002, nodeIpAddr:127.0.0.1/8, port:8001 }
不能连接到集群. 53163002
Quitting system. Set makeMasterOnError flag to make the node master. 53163002
liyuechun:go yuechunli$
获取相关帮助信息
$ ./bin/main -h
liyuechun:go yuechunli$ ./bin/main -h
Usage 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$
启动Node1主节点
$ ./bin/main --makeMasterOnError
liyuechun:go yuechunli$ ./bin/main --makeMasterOnError
My details: NodeInfo:{ nodeId:82381143, nodeIpAddr:127.0.0.1/8, port:8001 }
未连接到集群. 82381143
Will start this node as master.
添加节点Node2到集群
$ ./bin/main --myport 8002 --clusterip 127.0.0.1:8001
添加节点Node3到集群
main --myport 8004 --clusterip 127.0.0.1:8001
添加节点Node4到集群
$ main --myport 8003 --clusterip 127.0.0.1:8002
![](http://upload-images.jianshu.io/upload_images/14298671-b0d743a90a4b2d0a.png)
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