How to execute a function under limited time (eg under 5 minutes) in Python 3?-CodePudding

I have this line of code ("model.predict(image=img)") that I want to stop executing if it is taking longer than 5 minutes. Is there an easy way or library in python I can use to achieve this?

for filename in os.listdir():
    if filename.endswith(".jpg") or filename.endswith(".png"):
        print(filename)
        img = DataURI.from_file(filename)
        #This should run for no longer than 5 minutes
        output = model.predict(image=img)
        #if this took more than 5 minutes to run, use "continue"
        #continue

CodePudding user response：

You can use something like this:

for filename in os.listdir():
if filename.endswith(".jpg") or filename.endswith(".png"):
    print(filename)

    for x in range(0, 300)  #Converting Minutes to seconds so 300
        try:
            img = DataURI.from_file(filename)
            output = model.predict(image=img)
            break
                          
        except:
            time.sleep(1)
                    

    #if this took more than 5 minutes to run, use "continue"
    #continue

What this will do is like it will essentially try to check for it every 1 second until it is completely 5 minutes.

Or If this does't work you may refer this post which might help Link: Timeout on a function call

CodePudding user response：

Your model.predict() method is CPU bound operation probably. In Linux, you can use signal mechanism that will interrupt your current operation, but Windows OS has no all POSIX signal features, so we should use thread or multiprocess to interrupt/terminate any operation. Python gives a good option to terminate a thread using ctypes.pythonapi.PyThreadState_SetAsyncExc, but this will not terminate the thread before the I/O operation is finished

Here is a simple example :

import threading
import ctypes
import time

class TimeoutException(Exception):
    pass


def f(arg):
    while 1:
        time.sleep(1) 
        print("hello")       


class Timeout(threading.Thread):
    def __init__(self,func,arg,timeout):
        self.func = func
        self.arg = arg

        self.thread_ident = None
        self.output = None

        self.wait_for_finish = threading.Event()
        threading.Thread.__init__(self)

        self.killer = threading.Timer(timeout, self.raise_exception)
        self.killer.start()

        self.start()
        self.wait_for_finish.wait()

    def raise_exception(self):
        ctypes.pythonapi.PyThreadState_SetAsyncExc(ctypes.c_long(self.thread_ident),
                                                       ctypes.py_object(TimeoutException))
    def run(self):
        self.thread_ident = threading.get_ident()
        try:
            self.output = self.func(self.arg)

        except TimeoutException:
            self.output = "Timeout exception" 

        finally:
            self.wait_for_finish.set()
            self.killer.cancel()

output = Timeout(func=f, arg=5, timeout = 5).output
print(output)

You can also look at this