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)