##########
# on the virsh containers, DNS resolution using gethostbyaddr
# won't work fine, for the hosts under .pl.sophia.inria.fr
# although these IPs can be reversed from virtually everywhere else
#
# this has started with something around fedora35 so I am suspecting python-3.10
#
# in any case, here's a quick and dirty workaround, as I have bumped my head
# against the screen for two good hours and not found any single clue
# about how to deal with this properly

import socket
import subprocess

def workaround_gethostbyaddr(ip):
    try:
        return socket.gethostbyaddr(ip)[0]
    except:
        # if that fails, try again using the `host` command
        # which - surprisingly enough - works quite fine
        # inside the containers
        command = f"host {ip} 8.8.8.8"
        completed = subprocess.run(command, shell=True, capture_output=True)
        pieces = completed.stdout.decode().split("domain name pointer ")
        if len(pieces) == 2:
            return pieces[1].replace(".\n", "")
        else:
            return None