go - 如何在特定部分创建一个具有接口(interface)名称的文件，然后从另一个文件中解析以修改 GO 中数据的接口(interface)？

Question

我正在构建一个程序来更改 Ubuntu 18.04.1 LTS 中机器的 IP 地址。所以基本上我是用

创建一个 YAML 文件模板

network:
   ethernets:
      {INTERFACE}:
          dhcp4: no
          addresses: [{IP}/24]
          gateway4: {GATEWAY}
          optional: true
          nameservers:
           addresses: [{DNS}]
     {INTERFACE2}:
          dhcp4: no
          addresses: [{IP2}/24]
          gateway4: {GATEWAY2}
          optional: true
          nameservers:
           addresses: [{DNS2}]

现在我需要扫描此模板文件并通过 JSON 调用或作为 CLI 中的参数添加来自另一个文件的值。

因此应用程序将采用预先准备好的模板文件。例如yaml文件的示例模板。

需要3个参数这个模板文件，一个翻译文件(JSON)，以及输出

翻译文件也可以在命令行上解析

它基于2列，IP等搜索变量及其新值该实用程序将搜索 {IP} 变量并将其替换为第二列值。

在 CLI 上它可能看起来像这样:

./searchreplace -intemplate='templateip.yaml' -translation='{IP},xxx.x.x.x; {SUBNET},yyy.yyy.yyy.y} -outfile=/tmp/newipfile.yaml

我当前的代码对数据进行硬编码并更改 IP，但我希望它位于单独的模板文件中。这是我当前的代码

    package main

import (
    "bufio"
    "fmt"
    "log"
    "net"
    "os"
    "os/exec"
    "regexp"
    "strings"
)

var pathdelete = "/etc/netplan/01-network-manager-all.yaml"
var ipv4Regex = regexp.MustCompile(`^(?:[0-9]{1,3}\.){3}[0-9]{1,3}/[0-9]+$`)
var gatewayRegex = regexp.MustCompile(`^(?:[0-9]{1,3}\.){3}[0-9]{1,3}$`)
var nsRegex = regexp.MustCompile(`^(?:[0-9]\.){3}[0-9]{1,3}\,(?:[0-9]\.){3}[0-9]{1,3}$`)
var nicRegex = regexp.MustCompile(`e([a-z]+)`)

func main() {
    reader := bufio.NewReader(os.Stdin)
    fmt.Print("Enter the IP address: ")
    IPaddress, _ := reader.ReadString('\n')
    IPaddress = strings.TrimSuffix(IPaddress, "\n")

    //sanity check
    testInput := net.ParseIP(IPaddress)
    if testInput.To4() == nil {
        fmt.Printf("%v is not a valid IPv4 address\n", testInput)
    } else {
        fmt.Printf("It is a valid IP address\n")
        writeFile()
        readFile()
    }
}
func writeFile() {
    err01 := os.Truncate(pathdelete, 0)
    if err01 != nil {
        log.Fatal(err01)
    }

    //reading Network Cards
    reader := bufio.NewReader(os.Stdin)
    fmt.Print("Enter the Ethernet Card (for example : 'ens0N' or 'eth0') ")
    nic, _ := reader.ReadString('\n')
    nic = strings.TrimSuffix(nic, "\n")
    if nicRegex.MatchString(nic) {
    } else {
        log.Fatal("Please check the name of the NIC Card you have entered")
        os.Exit(1)
    }

    //reading IP Address and DNS
    fmt.Print("Enter the IP address along with the DNS in the format xxx.xxx.x.xxx/yy ")
    IP, _ := reader.ReadString('\n')
    IP = strings.TrimSuffix(IP, "\n")

    if ipv4Regex.MatchString(IP) {
    } else {
        log.Fatal("Please check the IP address you have entered")
        os.Exit(1)
    }

    //reading Gateway
    fmt.Print("Enter the gateway in the format xxx.xxx.x.x ")
    gateway, _ := reader.ReadString('\n')
    gateway = strings.TrimSuffix(gateway, "\n")
    if gatewayRegex.MatchString(gateway) {
    } else {
        log.Fatal("Please check the Gateway you have entered")
        os.Exit(1)
    }

    //reading Name servers
    fmt.Print("Enter the nameservers seperated by comma(,) in the format x.x.x.x,y.y.y.y ")
    ns, _ := reader.ReadString('\n')
    ns = strings.TrimSuffix(ns, "\n")
    if nsRegex.MatchString(ns) {
    } else {
        log.Fatal("Please check the Name Servers you have entered")
        os.Exit(1)
    }

    // open file using READ & WRITE permission
    var file, err = os.OpenFile(pathdelete, os.O_RDWR, 0644)
    checkError(err)
    defer file.Close()

    // write some text to file
    _, err = file.WriteString("# Let NetworkManager manage all devices on this system\nnetwork:\n  version: 2\n  renderer: NetworkManager\n")
    if err != nil {
        fmt.Println(err.Error())
        return //must return here for defer statements to be called
    }
    _, err = file.WriteString("  ethernets:\n    " + nic + ":\n      dhcp4: no\n      dhcp6: no\n")
    if err != nil {
        fmt.Println(err.Error())
        return //same as above
    }
    _, err = file.WriteString("      addresses: [" + IP + "]\n      gateway4: " + gateway + "\n      nameservers:\n        addresses: [" + ns + "]")
    if err != nil {
        fmt.Println(err.Error())
        return //same as above
    }

    // save changes
    err = file.Sync()
    if err != nil {
        fmt.Println(err.Error())
        return //same as above
    }
    applyCmd := exec.Command("bash", "-c", "sudo netplan apply")
    _, err2 := applyCmd.Output()
    if err2 != nil {
        panic(err2)
    }
}

func readFile() {
    // re-open file
    var file, err = os.OpenFile(pathdelete, os.O_RDWR, 0644)
    checkError(err)
    defer file.Close()

    // read file
    var text = make([]byte, 1024)
    n, err := file.Read(text)
    if n > 0 {
        fmt.Println("\nThe data you have entered is \n ")
        fmt.Println(string(text))
    }
    //if there is an error while reading
    //just print however much was read if any
    //at return file will be closed
}

func checkError(err error) {
    if err != nil {
        fmt.Println(err.Error())
        os.Exit(1)
    }
}

Answer 1

我能够通过转换命令行输入来实现这一点

./program --xyz.yaml --{interface} eth0 --IPaddress 192.168.1.233/24 --{gateway} 192.168.0.1 --DNS 8.8.3.8,8.8.8.3

我使用映射函数将 CLI 映射到字符串

func manyRandomArg() map[string]string {
    rv := make(map[string]string)
    for ix, x := range os.Args {
        if x[:2] == "--" {
            rv[x] = os.Args[ix+1]
        }
    }
    return rv
}

然后我只对键进行了排序，并进行了搜索替换功能

keys := make([]string, 0, len(rv))
    for key := range rv {
        keys = append(keys, key)
    }
    sort.Strings(keys) //sort keys alphabetically

必须修剪 key 中的“--”部分

key0 = trimLeftChars(keys[0], 2)

使用的字符串替换函数是

r := strings.NewReplacer(key0, rv[keys[0]], key1, rv[keys[1]], key2, rv[keys[2]], key3, rv[keys[3]], key4, rv[keys[4]])