如何从Handler类函数退出看门狗/ Python脚本？

Question

I have a script that is watching a folder for a file to be received. If the file is NOT received in X amount of time I want to be alerted, if it is received I want to exit the script. I plan to use Windows scheduled task to start/stop the script (because I don't know how to recycle it in Python). I'm currently stuck on trying to exit out of Watchdog/Python WHEN the file is received (since I only want alert if it isn't).

In the Handler Class I added a call to the quitter function on the if the event.event_type is detected. However, it doesn't exit and continues through till the timeout value is reached.

Here's what I have so far:

import time
from watchdog.observers import Observer
from watchdog.events import FileSystemEventHandler
import smtplib
import sys

file_rec = False

class Watcher:
    DIRECTORY_TO_WATCH = r"C:\Temp"

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

    def run(self):
        t_end = time.time() + 5 * 3 # Configure timeout value
        global file_rec
        event_handler = Handler()
        self.observer.schedule(event_handler, self.DIRECTORY_TO_WATCH, recursive=False)
        self.observer.start()
        try:
            while not file_rec:
                if time.time() > t_end: # If timeout reached file not created -- send email
                    email()

                else:
                    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:
            return None

        elif event.event_type == 'created':
            # File has been received, can now quit watching
            global file_rec
            file_rec = True
            quitter()

if __name__ == '__main__':

    def email():
        createMsg = "File XXX on Server XXX has not been received, manual intervention required."
        sender = 'NoReply@mydomain.com'
        receiver = 'test.user@mydomain.com'
        message = """From: No Reply <NoReply@mydomain.com>
                            TO: Test User <test.user@mydomain.com>
                            Subject: File Not Received

                            Attention Required: """ + str(createMsg)
        mail = smtplib.SMTP('email.mydomain.com', 25)
        mail.ehlo()
        #mail.starttls()
        mail.sendmail(sender, receiver, message)
        mail.close()
        quitter()

    def quitter():
        sys.exit()

    w = Watcher()
    w.run()

Answer 1

I had the same problem. I solved passing the observer to the handler extended constructor

from watchdog.events import FileSystemEventHandler


class MyHandler(FileSystemEventHandler):
    def __init__(self, observer):
        object.__init__(self)
        self.observer = observer

    def process(self, event):
        """
        event.event_type 
            'modified' | 'created' | 'moved' | 'deleted'
        event.is_directory
            True | False
        event.src_path
            path/to/observed/file
        """
        # the file will be processed there
        print event.src_path, event.event_type  # print now only for debug
        self.observer.stop()
        print "stopped"

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

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