How to execute a function asynchronously every 60 seconds in Python?

I want to execute a function every 60 seconds on Python but I don't want to be blocked meanwhile.

How can I do it asynchronously?

import threading
import time

def f():
    print("hello world")
    threading.Timer(3, f).start()

if __name__ == '__main__':
    f()    
    time.sleep(20)

With this code, the function f is executed every 3 seconds within the 20 seconds time.time. At the end it gives an error and I think that it is because the threading.timer has not been canceled.

How can I cancel it?

Thanks in advance!

You could try the threading.Timer class: http://docs.python.org/library/threading.html#timer-objects.

import threading

def f(f_stop):
    # do something here ...
    if not f_stop.is_set():
        # call f() again in 60 seconds
        threading.Timer(60, f, [f_stop]).start()

f_stop = threading.Event()
# start calling f now and every 60 sec thereafter
f(f_stop)

# stop the thread when needed
#f_stop.set()

The simplest way is to create a background thread that runs something every 60 seconds. A trivial implementation is:

class BackgroundTimer(Thread):   
   def run(self):
      while 1:
        Time.sleep(60)
        # do something


# ... SNIP ...
# Inside your main thread
# ... SNIP ...

timer = BackgroundTimer()
timer.start()

Obviously, this if the "do something" takes a long time, you'll need to accommodate for it in your sleep statement. But this serves as a good approximation.

I googled around and found the Python circuits Framework, which makes it possible to wait
for a particular event.

The .callEvent(self, event, *channels) method of circuits contains a fire and suspend-until-response functionality, the documentation says:

Fire the given event to the specified channels and suspend execution until it has been dispatched. This method may only be invoked as argument to a yield on the top execution level of a handler (e.g. "yield self.callEvent(event)"). It effectively creates and returns a generator that will be invoked by the main loop until the event has been dispatched (see :func:circuits.core.handlers.handler).

I hope you find it as useful as I do :)
./regards