foobar.py

#! /usr/bin/env python

import threading
global_var = { 'handler': None, 'sec_wait': 1.0 }

def cb_success ():
    print( 'success!' )

def cb_cancel ():
    if global_var['sec_wait'] >= 5.0:
        print('canceling')
        cb_success()
        global_var['handler'].cancel()
    else:
        print( 'wait: %d' % global_var['sec_wait'] )
        func_master()

def func_master():
    w = global_var['sec_wait'] = global_var['sec_wait'] + 1.0
    print( 'master: wait: %d' % w )
    global_var['handler'] = threading.Timer( w, cb_cancel )
    global_var['handler'].start()

func_master()