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I'm working on a simple watchdog script that will run md5sum on some very large images uploaded to our FTP. Watchdog doesn't seem to have a IN_CLOSE_WRITE event which exists in pyinotify. I tried checking if the file is still open as a work around but that does not work. Does anyone know a workaround to getting close_write event from watchdog?

import sys
import time

from watchdog.events import FileSystemEventHandler
from watchdog.observers import Observer


path = sys.argv[1]

class MyEventHandler(FileSystemEventHandler):
    def on_modified(self, event):
        print "File uploaded"
        # Is file still uploading?
        f = open(event.src_path)
        if f.closed:
            print "....run md5 & email admin"


event_handler = MyEventHandler()
observer = Observer()
observer.schedule(event_handler, path, recursive=True)
observer.start()
try:
    while True:
        time.sleep(1)
except KeyboardInterrupt:
    observer.stop()
observer.join()

1 Answer 1

2

Apparently that's not really possible with watchdog. Since watchdog tries to be platform-independent, it only handles events that can be detected on all platforms. There is another question that is relevant: Python (Watchdog) - Waiting for file to be created correctly

Also there is a issue on github, which is closed (basically wontfix): https://github.com/gorakhargosh/watchdog/issues/184

So it seems that going with pyinotify is probably the best option.

2
  • I have recently seen a project that uses another approach, by using ctypes to call into libc directly: github.com/uktrade/mobius3/blob/master/mobius3.py#L57 Just found that approach interesting, for me pyinotify worked well.
    – jeverling
    Commented Mar 29, 2020 at 21:18
  • A "couple" years later, but it looks like they did add a on_closed for linux now (not documented (yet)), for anyone who happens to stumple across this SO post Commented Aug 1, 2023 at 23:04

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