Python如何实现定时器功能

#!/usr/bin/env python
from threading import Timer
import time
timer_interval=1
def delayrun():
 print 'running'
t=Timer(timer_interval,delayrun)
t.start()
while True:
 time.sleep(0.1)
 print 'main running'

import time
import sys
import signal
import datetime
import threading
#定时器
def schedule_update():
t = threading.Timer(0, event_func)
t.setDaemon(True)
t.start()
#执行函数
def event_func():
now_time = datetime.datetime.now().strftime('%Y-%m-%d %H:%M:%S')
print(now_time)
exec_update()
#update_openvas_dbs_from_cache()
interval_time = delay_time()
t = threading.Timer(interval_time, event_func)
t.setDaemon(True)
t.start()
#取时间点
def delay_time():
# now time
now_time = datetime.datetime.now()
# tomorrow time
next_time = now_time + datetime.timedelta(days=+1)
next_year = next_time.date().year
next_month = next_time.date().month
next_day = next_time.date().day
# get tomorrow 00:00
next_time = datetime.datetime.strptime(str(next_year)+"-"+str(next_month)+"-"+str(next_day)+" 00:00:00", "%Y-%m-%d %H:%M:%S")
# get secondes
delay_time = (next_time - now_time).total_seconds()
return delay_time
def quit_sys(signum, frame):
sys.exit()
#接收C
if __name__ == "__main__":
try:
signal.signal(signal.SIGINT, quit_sys)
signal.signal(signal.SIGTERM, quit_sys)
schedule_update()
print("schedule_update server starting up...\nHit Ctrl-C to quit.\n")
while 1:
time.sleep(1)
except Exception as e:
print(e)