Go tool to get preferred network interface

interfaces.go

package main

import (
        "net"
        "strings"
)

func main() {
        preffered, list, err := GetPublicInterface()

        if err != nil {
                panic(err)
        }

        if len(preffered) == 0 {
                println(list[0])
        } else {
                println(preffered)
        }
}

func GetPublicInterface() (string, []string, error) {
        interfaces, err := net.Interfaces()

        if err != nil {
                return "", nil, err
        }

        list := make([]string, 0)
        for _, iface := range interfaces {
                if iface.Flags&net.FlagUp != 0 && iface.Flags&net.FlagBroadcast != 0 && !isNetworkBridge(iface.Name) &&
                        !(iface.Flags&net.FlagLoopback != 0) && !isTapAdapter(iface.Name) && !isTunAdapter(iface.Name) {
                        list = append(list, iface.Name)
                }
        }

        if len(list) == 0 {
                return "", list, nil
        }

        for _, iface := range list {
                if isPreferred(iface) {
                        return iface, list, nil
                }
        }

        return "", list, nil
}

func isNetworkBridge(iface string) bool {
        return strings.HasPrefix(iface, "vmbr")
}

func isTapAdapter(iface string) bool {
        return strings.HasPrefix(iface, "tap")
}

func isTunAdapter(iface string) bool {
        return strings.HasPrefix(iface, "tun")
}

func isPreferred(iface string) bool {
        return strings.HasPrefix(iface, "eth") || strings.HasPrefix(iface, "ens")
}