Running one function without stopping another

Question

How can I run a timer while asking for user input from the console? I was reading about multiprocessing, and I tried to use this answer: Python: Executing multiple functions simultaneously. When I tried to get it going, it gave me a bunch of framework errors.

Right now it runs start_timer(), but then stops it when it runs cut_wire().

Here's my start_timer function:

def start_timer():
    global timer
    timer = 10
    while timer > 0:
        time.sleep(1)
        timer -= 1
        sys.stdout.write ("There's only %i seconds left. Good luck. \r" % (timer))
        sys.stdout.flush()
        cut_wire()
    if timer == 0:
        print("Boom!")
        sys.exit()

and this is the cut_wire function:

def cut_wire():
    wire_choice = raw_input("\n> ")
    if wire_choice == "cut wire" or wire_choice == "Cut Wire":
        stop_timer()
    else:
        print("Boom!")
        sys.exit()

Answer 1

Of course it stops running when it plays the cut_wire function because "raw_input" command reads the text and wait for the user to put the text and press enter.

My suggestion is to check for they key press "Enter" and when then key was press, read the line. If the key wasn't press, just continue with your timer.

Regards.

Answer 2

Instead of using raw_input() use this function taken from here.

def readInput( caption, timeout = 1):
start_time = time.time()
sys.stdout.write('\n%s:'%(caption));
input = ''
while True:
    if msvcrt.kbhit():
        chr = msvcrt.getche()
        if ord(chr) == 13: # enter_key
            break
        elif ord(chr) >= 32: #space_char
            input += chr
    if len(input) == 0 and (time.time() - start_time) > timeout:
        break

print ''  # needed to move to next line
if len(input) > 0:
    return input
else:
    return ""

Thearding option

To make sure that both functions run completely simultaneously you can use this example of threading event:

import threading
event = threading.Event()
th = theading.Thread(target=start_timer, args=(event, ))
th1 = theading.Thread(target=cut_wire, args=(event, ))
th.start()
th1.start()
th.join()
th1.join()

In your function you can set an event using event.set(), check it using event.is_set() and clear it using event.clear().