Python watchdog windows wait till copy finishes

Question

I am using the Python watchdog module on a Windows 2012 server to monitor new files appearing on a shared drive. When watchdog notices the new file it kicks off a database restore process.

However, it seems that watchdog will attempt to restore the file the second it is created and not wait till the file has finished copying to the shared drive. So I changed the event to on_modified but there are two on_modified events, one when the file is initially being copied and one when it is finished being copied.

How can I handle the two on_modified events to only fire when the file being copied to the shared drive has finished?

What happens when multiple files are copied to the shared drive at the same time?

Here is my code

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

class NewFile(FileSystemEventHandler):
    def process(self, event):
        if event.is_directory:
            return

    if event.event_type == 'modified':            
        if getext(event.src_path) == 'gz':
            load_pgdump(event.src_path)

    def on_modified(self, event):
        self.process(event)

def getext(filename):
    "Get the file extension"
    file_ext = filename.split(".",1)[1]
    return file_ext

def load_pgdump(src_path):    
    restore = 'pg_restore command ' + src_path
    subprocess.call(restore, shell=True)

def main():
    event_handler = NewFile()
    observer = Observer()
    observer.schedule(event_handler, path='Y:\\', recursive=True)
    observer.start()

    try:
        while True:
            time.sleep(1)
    except KeyboardInterrupt:
        observer.stop()
    observer.join()

if __name__ == '__main__':
    main()

Answer 1

In your on_modified event, just wait until the file is finished being copied, via watching the filesize.

Offering a Simpler Loop:

historicalSize = -1
while (historicalSize != os.path.getsize(filename)):
  historicalSize = os.path.getsize(filename)
  time.sleep(1)
print "file copy has now finished"