python watchdog

watchdir.py

#!/usr/bin/env python3
"""Script is used to observe filesystem changes
of given directory using 'watchdog' api

Usage:
    watchdir <PATH>

version 1.0
"""
import logging
import os
import sys
import time
from watchdog.events import FileSystemEventHandler
from watchdog.observers import Observer


class OnObserver:
    """Observer class
    which is used to start and stop monitoring
    """

    def __init__(self, target):
        """constructor of Observer takes one input argument
        instance attributes:
            observer (Observer): object of watchdog
            watch_dir (str): target directory to monitor
        Args:
            target(str): directory path as input argument
        """
        self.observer = Observer()
        self.watch_dir = os.path.expanduser(target)

    def run(self):
        """function to start monitoring
        observer sends event to event_handler when file changed in watchdir
        event_handler obj will then execute its coressponding method
        """
        event_handler = EventHandler()
        self.observer.schedule(event_handler, self.watch_dir, recursive=True)
        self.observer.start()
        try:
            while True:
                time.sleep(5)
        except KeyboardInterrupt:
            self.observer.stop()
            print("Observer Stopped")

        self.observer.join()


class EventHandler(FileSystemEventHandler):
    """EventHandler class
    override methods of parent class to do disired action on change
    """

    def on_any_event(self, event):
        """override method to log event with datetime
        """
        if event.is_directory:
            return None
        logging.info("{}: {}".format(event.event_type, event.src_path))

    # work only inside observed path
    def on_moved(self, event):
        """override method to notify movement
        work only inside observed path
        """
        print("Moved: {} to {}".format(event.src_path, event.dest_path))


def main():
    # open doc
    if len(sys.argv) == 2 and (sys.argv[1] == '-h' or sys.argv[1] == '--help'):
        print(__doc__)
        sys.exit(1)

    # set the format for logging info
    logging.basicConfig(level=logging.INFO,
                        format='%(asctime)s - %(message)s',
                        datefmt='%Y-%m-%d %H:%M:%S')

    # start monitoring at given path
    path = sys.argv[1] if len(sys.argv) > 1 else '.'
    watch = OnObserver(target=path)
    watch.run()


if __name__ == '__main__':
    main()