import threading
import logging
log = logging.getLogger("mysc.repeating_timer")

class RepeatingTimer(threading.Thread):
 """Call a function after a specified number of seconds, it will then repeat again after the specified number of seconds
    Note: If the function provided takes time to execute, this time is NOT taken from the next wait period

 t = RepeatingTimer(30.0, f, args=[], kwargs={})
 t.start()
 t.cancel() # stop the timer's actions
 """

 def __init__(self, interval, function, daemon=True, *args, **kwargs):
  threading.Thread.__init__(self)
  self.daemon = daemon
  self.interval = float(interval)
  self.function = function
  self.args = args
  self.kwargs = kwargs
  self.finished = threading.Event()

 def cancel(self):
  """Stop the timer if it hasn't finished yet"""
  log.debug("Stopping repeater for %s" % (self.function,))
  self.finished.set()
 stop = cancel

 def run(self):
  while not self.finished.is_set():
   self.finished.wait(self.interval)
   if not self.finished.is_set():  #In case someone has canceled while waiting
    try:
     self.function(*self.args, **self.kwargs)
    except:
     log.exception("Execution failed. Function: %r args: %r and kwargs: %r" % (self.function, self.args, self.kwargs))