Instantaneous file delete using Python

I have a script that is on a loop that waits for certain folders to be generated and then deletes the images inside of them with "_GOOD" on their filename (the images are also being generated). The script runs smoothly when simulated on my laptop using my local folders. However, when I run this script on the machine it is intended to be used, the file deletion is not continuous. It will delete one or two images then goes back to the loop even though there are new images generated by the machine.

Note that this machine generates images very fast. It generates the images as soon as it captures them. Could this be the problem? My script cannot comprehend the speed of image generation of the machine? Or is there something wrong with my code? Appreciate the inputs!

Below is the code:

reel_folders_src = \\directory_of_folders_that_are_yet_to_exist\\

def wait_for_reelfolders(folder_paths):
  last_modified_folder = {folder_path3: None for folder_path3 in folder_paths}

  while True:
    print("Waiting for other reel folders")
   
    for folder_path3 in folder_paths:
      if os.path.exists(folder_path3):
        current_modified = os.path.getmtime(folder_path3)
        if last_modified_folder[folder_path3] is None or current_modified > last_modified_folder[folder_path3]:
          last_modified_folder[folder_path3] = current_modified
          #delete_files_in_folder(folder_path3)
          for file_name in os.listdir(folder_path3):
            file_path = os.path.join(folder_path3, file_name)
            print(f"Ongoing GOOD image purge in folder '{folder_path3}'")
            if "_GOOD_" in file_path:
              os.remove(file_path)

#These are the folders that are yet to be generated by the machine along with images inside of them 
reel_folders = [reel_folders_src + '\\' + "Reel2", reel_folders_src + '\\' + "Reel3", reel_folders_src + '\\' + "Reel4"]

#Execute function 
wait_for_reelfolders(reel_folders)

You have some application that is creating files in a directory. Such files may have _GOOD_ in their pathname.

The code in the question is polling a list of directories to see if they've been modified (since they were last checked - if ever). If the directory appears to have been modified, files containing _GOOD_ within that directory will be deleted.

HOWEVER While this code is deleting files, the other application may be creating them! Therefore the output from os.listdir() is merely a snapshot and files matching the pattern may be missed.

As an aside, it's worth noting that your hardware will "thrash" when you run the wait_for_reelfolders() function because the while loop is infinite and there are no delays implemented

Here's what I would suggest:

import time
import os
import glob
import threading

EVENT = threading.Event()

reel_folders_src = r'c:\Reels'

def wait_for_reel_folders(*folder_paths):
    while not EVENT.is_set():
        for folder in folder_paths:
            for good in glob.glob(os.path.join(folder, '*_GOOD_*')):
                os.remove(good)
        time.sleep(1) # give the computer a break

reel_folders = [os.path.join(reel_folders_src, f'Reel{r}') for r in range(2, 5)]

(thread := threading.Thread(target=wait_for_reel_folders, args=reel_folders)).start()

time.sleep(10) # run thread for 10 seconds
EVENT.set() # tells thread to stop
thread.join() # wait for thread to terminate

This will continually monitor the folders listed in folder_paths until such time as the controlling application tells it to stop by setting the Event.

One convenient feature of glob() is that if the pattern being searched for doesn't exist it simply returns an empty list - i.e., no exception. This means that the folders that may not yet exist are ignored