find_good_ntp_server.py

#!/usr/bin/env python
from dns import resolver  # dnspython
from dns import reversename
from dns import rdatatype
from ntplib import NTPClient  # ntplib
from ntplib import NTPException


NTP_NAME = '0.europe.pool.ntp.org'
NTP_NAME = '0.us.pool.ntp.org'
QUERIES = 100


def main():
    resolver.get_default_resolver().nameservers = [res.address for res in resolver.query('f.ntpns.org.')]
    candidates = set()
    for _ in range(QUERIES):
        candidates.update(el.address for el in resolver.query(NTP_NAME))
    ntp = NTPClient()
    times = {}
    for el in candidates:
        try:
            resp = ntp.request(el, version=3)
        except NTPException:
            pass
        times[el] = resp.delay
    sorted_ips = sorted(times.items(), key=lambda x: x[1])

    resolver.get_default_resolver().nameservers = ['8.8.8.8', '8.8.4.4']
    selected_ips = [a[0] for a in sorted_ips[:10]]
    selected_names = []
    for ip in selected_ips:
        try:
            res = resolver.query(reversename.from_address(ip), rdtype=rdatatype.PTR)
            selected_names.append(res[0].to_text())
        except resolver.NXDOMAIN:
            pass
    print('These are the best servers I could find:\n{}'.format('\n'.join(selected_names)))

if __name__ == '__main__':
    main()