Python watchdog not processing all files in Windows?

Question

Got this watchdog looking at a folder and using a handler to LPR all newly created files to a specific printer (defined on a command prompt batch). Problem is that when you submit a lot of files the watchdog will only process 8, 9, 10 or 11 of them... What am I doing wrong? I'm pretty sure there's something wrong with my 'print queue' (maybe getting corrupted) or with the Windows processing timeout...

The script is:

import os
import os.path
import subprocess
from subprocess import *
import sys
import time
from watchdog.observers import Observer
from watchdog.events import FileSystemEventHandler

class Watcher:
    DIRECTORY_TO_WATCH = r"C:\Users\50544342\Desktop\Newfolder3\Files"

    def __init__(self):
        self.observer = Observer()

    def run(self):
        event_handler = Handler()
        self.observer.schedule(event_handler, self.DIRECTORY_TO_WATCH, recursive=True)
        self.observer.start()
        try:
            while True:
                time.sleep(5)
        except:
            self.observer.stop()
            print("Error")

        self.observer.join()


class Handler(FileSystemEventHandler):

    @staticmethod
    def on_any_event(event):
        if event.is_directory:
            # LPR print from batch on any event.
            p = subprocess.Popen(['LPR.bat', event.src_path], stdout=PIPE, stderr=PIPE)
            output, errors = p.communicate()
            p.wait() # wait for process to terminate

        elif event.event_type == 'created':
            # LPR print from batch when a file is first created.
            p = subprocess.Popen(['LPR.bat', event.src_path], stdout=PIPE, stderr=PIPE)
            output, errors = p.communicate()
            p.wait() # wait for process to terminate


if __name__ == '__main__':
    w = Watcher()
    w.run()

The LPR.bat reads:

lpr.exe -S 127.0.0.1 -P Queue %1

Thanks in advance for any help or tips you may provide.

Answer 1

You should try changing the buffer size of watchdog. Look at this.

try to use a bigger buffer size: Value to change