Pause a thread/ execfile()
Babloo
pruthviraj.pb at gmail.com
Mon Oct 26 04:25:14 EDT 2009
On Oct 26, 1:01 pm, Sean DiZazzo <half.ital... at gmail.com> wrote:
> On Oct 25, 11:58 pm, Babloo <pruthviraj... at gmail.com> wrote:
>
>
>
> > i have a small python application with GUI (frontend) which has
> > various functions. I have a "RUN" button which runs python scripts in
> > the background . It basically calls execfile() function internally
> > which runs in a thread , to run the python script .
>
> > I want to implement a "PAUSE" feature which would pause the running
> > python script . So do that i have to either pause the thread in which
> > execfile() runs or pause execfile itself .
>
> > When the user presses "RUN" again then the python script should resume
> > running .
>
> > Any ideas how to pause the thread / pause execfile() . Any other ideas
> > for the same would be helpful .
>
> > Thanks
>
> I think you can do that with a threading.event(). In the gui, create
> a new threading.event() and pass it in to the worker thread. Set up
> your code in the worker so that on every iteration of "work", it
> checks to see if the event is set. If it finds it set, then it
> sleeps, but keeps checking until the event is unset. When unset
> again, it picks up and begins work again.
>
> In the gui, your pause button just sets and unsets the event, and the
> worker will find out and pause at the next iteration.
>
> Depending on what kind of work your worker thread is doing, it might
> be tough to structure the code so the event gets checked reasonably
> often. Hope this helps.
>
> ~Sean
>
> PS. Not sure this idea will hold up when using execfile()
Hi..
Thanks for the reply . Yes tried doing exactly what you have
suggested . i could show you the sample code .
But some how it doesn't work and main reason could be i am using
execfile() in the thread .
I was trying to set the event on the press of a button . It doesnt
pause the thread and instead keeps on executing .
Dont know what the problem could be ???
Sample code :-
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import threading
class TestThread(threading.Thread):
"""
A sample thread class
"""
def __init__(self):
"""
Constructor, setting initial variables
"""
self._stopevent = threading.Event()
self._sleepperiod = 1.0
threading.Thread.__init__(self, name="TestThread")
def run(self):
"""
overload of threading.thread.run()
main control loop
"""
print "%s starts" % (self.getName(),)
count = 0
while not self._stopevent.isSet():
count += 1
print "loop %d" % (count,)
self._stopevent.wait(self._sleepperiod)
print "%s ends" % (self.getName(),)
def join(self,timeout=None):
"""
Stop the thread
"""
self._stopevent.set()
threading.Thread.join(self, timeout)
if __name__ == "__main__":
testthread = TestThread()
testthread.start()
import time
time.sleep(10.0)
testthread.join()
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