My Tiny Timer Class

Just yesterday I posted about creating a new way of controlling and monitoring my Wemo light switches.  In the post I talked about having to develop a way of timing operations.  It was pretty simple and has worked well overnight, so I decided to put it in a python class and use it in the other parts of my system.

So you understand, I hate classes.  When c++ came around, and object oriented programming was all the rage, I resisted.  No, it wasn't that I couldn't accept change, it was that the crap they produced was incredibly hard to read.  Four pages of class definitions and sixteen lines of code may have been cool, but just try and debug it.  Especially with the tools available back then.  Well, it's been some years and objects have matured as well as the folk that created the mess back then.  Now, they're not as big a mess, maybe I should join the 21st century.  Sure, I use classes all the time; I just avoid writing them if at all possible; this is an exception.

So, here's my basic timer class.  Simple right?  Remember, the reason I did this was to keep control within a single thread thus avoiding deadlocks in code and locked up databases.

import time

class timer:
 _things = []
 
 def __init__(self, callback, seconds=1, minutes=0, hours=0):
  interval = (hours*60*60) + (minutes*60) + seconds
  actionTime = time.time() + interval
  self._things.append({"callback":callback,"interval":interval,"actionTime":actionTime})

 def tick(self):
  now = time.time()
  for i in self._things:
   if i["callback"] == None:
    continue
   if now >= i["actionTime"]:
    i["callback"]()
    i["actionTime"] += i["interval"]

checkTimer = timer(None)

''' This is code to test and illustrate the usage '''
def printSecond():
 print "second"
 
def printTwoSeconds():
 print "twoseconds"

def printMinute():
 print "minute"

if __name__ == "__main__":
 # First create any timers you need
 oneSecond = timer(printSecond, seconds=1)
 twoSeconds = timer(printTwoSeconds, seconds=2)
 minute = timer(printMinute, minutes=1)
 
 # now once in a while call tick to let them happen
 while True:
  checkTimer.tick()
  # a sleep lets the cpu have a rest to do other things.
  time.sleep(0.5)

It just keeps a list of the various timers I create to do things and steps through them to see if something needs to be done.  I included an instance by default so, when I use it, I don't have to create one.  It's easy to use and I may be extending it to handle other things that may need to be timed differently like: Every day at 3:00pm, feed the fish.  That takes more work parsing various parameters and such, but it's easy to extend.

Within the module is an example of how to use it.  This can be directly run under python, to see how it works, and how to use it.

I've already modified my module for the Wemo switches to use it, now I'm looking at the other modules to see if this would be appropriate there as well.