autotime.py

# Requires: ntplib (https://pypi.python.org/pypi/ntplib/)

import ctypes
import time
import ntplib

MAX_RETRIES = 10
RETRY_DELAY = 30
NTP_SERVERS = [
    "0.tw.pool.ntp.org",
    "0.asia.pool.ntp.org",
    "1.asia.pool.ntp.org",
    "2.asia.pool.ntp.org",
    "3.asia.pool.ntp.org"
]


class SYSTEMTIME(ctypes.Structure):
    _fields_ = [("wYear",         ctypes.c_ushort),
                ("wMonth",        ctypes.c_ushort),
                ("wDayOfWeek",    ctypes.c_ushort),
                ("wDay",          ctypes.c_ushort),
                ("wHour",         ctypes.c_ushort),
                ("wMinute",       ctypes.c_ushort),
                ("wSecond",       ctypes.c_ushort),
                ("wMilliseconds", ctypes.c_ushort)]


def get_network_time(server_list):
    client = ntplib.NTPClient()
    for server_address in server_list:
        print("Trying server: " + server_address)
        try:
            response = client.request(server_address, version=3)
        except ntplib.NTPException as ex:
            print("Failed: " + ex.args[0])
            continue
        local_time = time.localtime(response.tx_time)
        utc_time = time.gmtime(response.tx_time)
        print("Success! Current time: " + time.strftime("%Y-%m-%d %H:%M:%S", local_time))
        return utc_time
    print("Exhausted all servers.")
    return None


def set_system_time(utc_time):
    native_struct = SYSTEMTIME(utc_time.tm_year,
                               utc_time.tm_mon,
                               utc_time.tm_wday,
                               utc_time.tm_mday,
                               utc_time.tm_hour,
                               utc_time.tm_min,
                               utc_time.tm_sec)

    success = ctypes.windll.kernel32.SetSystemTime(ctypes.byref(native_struct))
    assert success != 0


def main():
    for i in range(MAX_RETRIES):
        utc_time = get_network_time(NTP_SERVERS)
        if utc_time is not None:
            set_system_time(utc_time)
            return
        time.sleep(RETRY_DELAY)
    print("Reached max retry count! Please try again later.")


if __name__ == "__main__":
    main()