Correct way to do timer function in Python

Question

Hi. I have a GUI application that needs to do something simple in the background (update a wx python progress bar, but that doesn't really matter). I see that there is a threading.timer class.. but there seems to be no way to make it repeat. So if I use the timer, I end up having to make a new thread on every single execution... like :

import threading
import time

def DoTheDew():
    print "I did it"
    t = threading.Timer(1, function=DoTheDew)
    t.daemon = True
    t.start()    

if __name__ == '__main__':
    t = threading.Timer(1, function=DoTheDew)
    t.daemon = True
    t.start()
    time.sleep(10)

This seems like I am making a bunch of threads that do 1 silly thing and die.. why not write it as :

import threading
import time

def DoTheDew():
    while True:
        print "I did it"
        time.sleep(1)


if __name__ == '__main__':
    t = threading.Thread(target=DoTheDew)
    t.daemon = True
    t.start()
    time.sleep(10)

Am I missing some way to make a timer keep doing something? Either of these options seems silly... I am looking for a timer more like a java.util.Timer that can schedule the thread to happen every second... If there isn't a way in Python, which of my above methods is better and why?

Answer 1

wxwindows has its own timer. It supports one shot, and reoccurring events.

Answer 2

A pattern more like this is probably what you should be doing, but it's hard to say because you didn't provide many details.

def do_background_work(self):
    # do work on a background thread, posting updates to the
    # GUI thread with CallAfter
    while True:
        # do stuff
        wx.CallAfter(self.update_progress, percent_complete)

def update_progress(self, percent_complete):
    # update the progress bar from the GUI thread
    self.gauge.SetValue(percent_complete)

def on_start_button(self, event):
    # start doing background work when the user hits a button
    thread = threading.Thread(target=self.do_background_work)
    thread.setDaemon(True)
    thread.start()