tiny golang to gather external ipv4/6 addresses using https://github.com/andreaskoch/myip

external_ip.go

///usr/bin/true; exec /usr/bin/env go run "$0" "$@"
//
//https://gist.github.com/gretel/1cadb5c626930cab7a0b8687aa710916
//usage:
//  $ external_ip.go
//  $ external_ip.go -4=true -6=true
//  $ external_ip.go -4=false -6=true

package main

import (
        "fmt"
        "flag"
        "github.com/andreaskoch/myip"
        "os"
)

// note, that variables are pointers
var fourFlag = flag.Bool("4", true, "output for version 6")
var sixFlag = flag.Bool("6", false, "output for version 4")

func main() {
    flag.Parse()
    if(*fourFlag == false && *sixFlag == false) {
        os.Exit(1)
    }
        remoteIPProvider := myip.NewRemoteIPProvider()
        if(*fourFlag) {
                remoteIPv4Addresses, remoteIPError := remoteIPProvider.GetIPv4Addresses()
                if remoteIPError != nil {
                        fmt.Fprintf(os.Stderr, "failed to determine ipv4 addresses: %s\n", remoteIPError.Error())
                        os.Exit(2)
                }
                fmt.Fprintf(os.Stdout, "%s\n", remoteIPv4Addresses[0])
        }
        if(*sixFlag) {
                remoteIPv6Addresses, remoteIPError := remoteIPProvider.GetIPv6Addresses()
                if remoteIPError != nil {
                        fmt.Fprintf(os.Stderr, "failed to determine ipv6 addresses: %s\n", remoteIPError.Error())
                        os.Exit(3)
                }
                fmt.Fprintf(os.Stdout, "%s\n", remoteIPv6Addresses[0])
        }
    os.Exit(0)
}