decorator using while loop

Question

Let's say I want to execute any function repeatedly for 5 seconds. I can do something like this:

def any_function(name):
  print(f"hello {name}")

import time
timeout = 5   # [seconds]
timeout_start = time.time()
while time.time() < timeout_start + timeout:
  time.sleep(1) # optional, just to slow down execution
  any_function("id3a") #could be any function

what if I want to make this while loop available for other functions, I tried to use a decorator - see below - but it breaks the while loop after the first iteration.

def decorator_function(original_function):
  import time
  timeout = 5   # [seconds]
  timeout_start = time.time()
  while time.time() < timeout_start + timeout:
    def wrapper_function(*args, **kwargs):
      time.sleep(1) # optional, just to slow down execution
      return original_function(*args,**kwargs)
    return wrapper_function
  
@decorator_function
def any_function(name):
  print(f"hello {name}")
  
any_function("id3a")

How would you do it?

Is it helpful? https://stackoverflow.com/questions/474528/what-is-the-best-way-to-repeatedly-execute-a-function-every-x-seconds — Eliran Turgeman, Aug 14 '20 at 16:51
@EliranTurgeman I think I got that part right, the problem here is how do I make it work for other functions, using I guess, a decorator — id3a, Aug 14 '20 at 17:14
`return wrapper_function` here you are returning and breaking function execution of `decorator_function` at the end of your `while` loop. That is why it is only executing once. additionally, you are just redefining `wrapper_function` over the course of 5 seconds. That's another reason it's only getting called once. Place your while loop inside of the `wrapper_function` you are returning and remove the inner `return` and you should be fine. — Axe319, Aug 14 '20 at 17:16

score 3 · Accepted Answer · answered Aug 14 '20 at 17:10

If you want to use a decorator, here is a working example:

import time


def scheduler(timeout=5, interval=0):
    def decorator(function):
        def wrapper(*args, **kwargs):
            timeout_start = time.time()
            while time.time() < timeout_start + timeout:
                time.sleep(interval)
                function(*args, **kwargs)
        return wrapper
    return decorator


@scheduler(timeout=5, interval=1)
def any_function(name):
    print(f'hello {name}')


any_function('id3a')

It gives the output:

hello id3a
hello id3a
hello id3a
hello id3a
hello id3a

If you want to create another function to call your function repeatedly, here is an example:

import time


def scheduler(function, timeout=5, interval=0):
    timeout_start = time.time()
    while time.time() < timeout_start + timeout:
        time.sleep(interval)
        function()


def any_function(name):
    print(f'hello {name}')


scheduler(lambda: any_function('id3a'), timeout=5, interval=1)

The output is:

hello id3a
hello id3a
hello id3a
hello id3a
hello id3a

decorator using while loop

1 Answers1