golang 定时刷新配置文件

Dear 丶 2022-06-08 09:08 357阅读 0赞

实时刷新配置文件例子，不多说 直接上代码

dir

➜  test tree
    .
    ├── app
    │   ├── de.tmpl.go
    │   └── demo.tmpl
    ├── linesearch.go
    ├── linked.go
    ├── snowflake.go
    └── template.go
    
    1 directory, 6 files

configfile

# [member] ETCD_NAME="$hostname" ETCD_DATA_DIR="/work/etcd" ETCD_LISTEN_PEER_URLS="http://k8s_master_ip:2380" ETCD_LISTEN_CLIENT_URLS="http://$hostip,http://k8s_master_ip:2379" #[cluster] ETCD_INITIAL_ADVERTISE_PEER_URLS="http://k8s_master_ip:2380" ETCD_INITIAL_CLUSTER="k8s_master_ip_name=http://k8s_master_ip:2380" ETCD_INITIAL_CLUSTER_STATE="new" ETCD_INITIAL_CLUSTER_TOKEN="etcd-cluster" ETCD_ADVERTISE_CLIENT_URLS="http://$hostip:2379" { {$PeerCount:=.PeerCount}} ETCD_INITIAL_CLUSTER="{ { range $index,$ele:=.Peers}}{ { if eq $index $PeerCount }}{ { .Hostname}}=http://{ { .Hostname}}:2380{ { else}}{ { .Hostname}}=http://{ { .Hostname}}:2380,{ { end}}{ { end}}" { { range $index,$ele:=.Peers}} server.{ {$index}}={ { .Hostname}}:2888:3888 { { end}} #$all server-0,server-1,server-2,server-3

--------------------

golang code

package main
    
    import (
        "fmt"
        "os"
        "net"
        "text/template"
        "strings"
        "io/ioutil"
        "encoding/hex"
        "crypto/md5"
        "time"
        "io"
    )
    
    func main() {
        t := time.NewTicker(10 * time.Second)
        fmt.Printf("server start time ================> %s \n",time.Now())
        for {
            select {
            case <-t.C:
                fmt.Printf("begin time ================> %s\n",time.Now())
                run()
                fmt.Printf("end time ================> %s\n",time.Now())
            //default:
            // fmt.Println("this is demo")
            }
    
        }
    }
    
    //hostip hostname peer all
    var OldMd5Sum string
    
    type Peer struct {
        Hostname string
    }
    type TemplateData struct {
        Peers     []Peer
        PeerCount int
        Hostname  string
        HostIp    string
    }
    
    func run() {
    
        filePath := os.Getenv("FILE_PATH")
        if filePath == "" {
            filePath = "app/demo.tmpl"
        }
    
        var templateData TemplateData
        configData := ""
        //check the file if exist
        ok, err := FileExists(filePath)
        if err != nil {
            fmt.Printf("the file is not exist %#v\n", err)
            return
        }
        //the file exist
        if ok {
            yes, err := Md5SumFile(filePath)
            if err == nil && !yes {
                filedata, err := ReadFile(filePath)
                if err != nil {
                    fmt.Println("\n", err)
                    return
                }
                configData = filedata
            } else {
                fmt.Printf("the file is not change or read file failed %#v\n", err)
                return
            }
            ALL := ""
            if configData != "" {
                if strings.Contains(configData, "$all") {
                    ALL = strings.Split(configData, "$all")[1]
                    serverlist := strings.Split(strings.Replace(ALL, " ", "", -1), ",")
                    serverLen := len(serverlist)
                    templateData.PeerCount = serverLen - 1
                    templateData.Peers = make([]Peer, 0)
                    var peer Peer
                    for _, server := range serverlist {
                        peer.Hostname = server
                        templateData.Peers = append(templateData.Peers, peer)
                    }
    
                } else {
                    fmt.Printf(" No $all parameter\n")
                    return
                }
    
                if strings.Contains(configData, "$hostname") {
                    configData = strings.Replace(configData, "$hostname", "{ {.Hostname}}", -1)
                }
    
                if strings.Contains(configData, "$hostip") {
                    configData = strings.Replace(configData, "$hostip", "{ {.HostIp}}", -1)
                }
    
            }
            fmt.Printf("configData=======================\n%s\n", configData)
    
            hostname, err := os.Hostname()
            if err != nil {
                fmt.Printf("get hostname failed \n", err)
                return
            }
            templateData.Hostname = hostname
    
            ns, err := net.LookupHost("www.baidu.cn")
            if err != nil {
                fmt.Fprintf(os.Stderr, "Err: %s", err.Error())
                return
            }
    
            for _, n := range ns {
                fmt.Fprintf(os.Stdout, "%s\n", n)
                templateData.HostIp = n
            }
    
            tpl, err := template.New("demo").Parse(configData)
            if err != nil {
                fmt.Printf("%s ", err)
                return
            }
            file, err := os.OpenFile("app/de.tmpl.go", os.O_RDWR, 0777)
            if err != nil {
                fmt.Printf("OpenFile failed %#v\n", err)
                return
            }
            defer file.Close()
            err = tpl.Execute(file, templateData)
            if err != nil {
                panic(err)
                return
            }
        } else {
            fmt.Printf("the file %s not exist or read the file %s failed \n ", filePath, filePath)
            return
        }
    
    }
    
    //判断文件是否存在
    func FileExists(filepath string) (bool, error) {
        _, err := os.Stat(filepath)
        if err == nil {
            return true, nil
        }
        return false, err
    }
    
    func ReadFile(filePath string) (string, error) {
        file, err := os.Open(filePath)
        if err != nil {
            fmt.Printf("Open file failed %#v\n", err)
            return "", err
        }
        defer file.Close()
        fileData, err := ioutil.ReadAll(file)
        if err != nil {
            fmt.Printf("ReadAll file failed %#v\n", err)
            return string(fileData), err
        }
    
        return string(fileData), nil
    }
    
    func Md5SumFile(filePath string) (bool, error) {
    
        file, err := os.Open(filePath)
        if err != nil {
            fmt.Printf("Open file failed %#v\n", err)
            return false, err
        }
    
        md5hash := md5.New()
        _, err = io.Copy(md5hash, file)
        if err != nil {
            fmt.Printf("io.Copy file failed %#v\n", err)
            return false, err
        }
    
        strSum := md5hash.Sum(nil)
        resMd5 := hex.EncodeToString(strSum)
    
        if OldMd5Sum != "" && resMd5 == OldMd5Sum {
            return true, nil
        }
        defer file.Close()
        OldMd5Sum = resMd5
        return false, nil
    }

result

# [member]
    ETCD_NAME="xinzhiyundeMacBook-Pro.local"
    ETCD_DATA_DIR="/work/etcd"
    ETCD_LISTEN_PEER_URLS="http://k8s_master_ip:2380"
    ETCD_LISTEN_CLIENT_URLS="http://119.75.213.61,http://k8s_master_ip:2379"
    #[cluster]
    ETCD_INITIAL_ADVERTISE_PEER_URLS="http://k8s_master_ip:2380"
    ETCD_INITIAL_CLUSTER="k8s_master_ip_name=http://k8s_master_ip:2380"
    ETCD_INITIAL_CLUSTER_STATE="new"
    ETCD_INITIAL_CLUSTER_TOKEN="etcd-cluster"
    ETCD_ADVERTISE_CLIENT_URLS="http://119.75.213.61:2379"
    
    
    ETCD_INITIAL_CLUSTER="server-0=http://server-0:2380,server-1=http://server-1:2380,server-2=http://server-2:2380,server-3=http://server-3:2380"
    
    server.0=server-0:2888:3888
    
    server.1=server-1:2888:3888
    
    server.2=server-2:2888:3888
    
    server.3=server-3:2888:3888
    
    #$all server-0,server-1,server-2,server-3-3