Process that monitors file system changes within directory and runs scripts on changed entities

monitor-file-changes.py

#!/usr/bin/python

import gamin
import time
from os.path import expanduser
import threading
import thread
import os
import Queue

class CallbackFactory():
    """
    Callback for file change monitor events
    """
    def __init__(self, monitor, dir, queue):
        self.dir = dir
        self.mon = monitor.mon
        self.monitor = monitor
        self.queue = queue

        self.EVENT_CHANGED = 1
        self.EVENT_DELETED = 2
        self.EVENT_START_EXECUTING = 3
        self.EVENT_STOP_EXECUTING = 4
        self.EVENT_CREATED = 5
        self.EVENT_MOVED = 6
        self.EVENT_ACKNOWLEDGE = 7
        self.EVENT_EXISTS = 8
        self.EVENT_END_EXIST = 9

    def callback(self, path, event):
        if event == self.EVENT_CREATED:
            created_path = self.dir + '/' + path
            if os.path.isdir(created_path):
                f = CallbackFactory(self.monitor, created_path, 
                                    self.queue)
                self.mon.watch_directory(created_path, f.callback)
                # Notify about all files in the created directory
                # ... 
            print "Created:", created_path
        if event == self.EVENT_DELETED:
            print "Deleted:", path
        if event == self.EVENT_CHANGED:
            print "Changed:", path
        if event == self.EVENT_MOVED:
            print "Moved:", path
        if event == self.EVENT_ACKNOWLEDGE:
            print "Ack:", path
        self.queue.put(path)

class MonitorThread(threading.Thread):

    def __init__(self, queue):
        threading.Thread.__init__(self)

        self.dir = expanduser('~/Desktop')
        self.mon = gamin.WatchMonitor()
        self.queue = queue

    def add_directories(self):
        f = CallbackFactory(self, self.dir, self.queue)
        self.mon.watch_directory(self.dir, f.callback)
        for root, folders, files in os.walk(self.dir):
            for folder in folders:
                dir = root + "/" + folder
                f = CallbackFactory(self, dir, self.queue)
                self.mon.watch_directory(dir, f.callback)
                print dir

    def run(self):
        print "Starting monitoring"
        self.add_directories()
        
        print "Entering infinite loop"
        while True:
            time.sleep(5)
            ret = self.mon.event_pending()
            if ret > 0:
                # ret = self.mon.handle_one_event() 
                ret = self.mon.handle_events()

        self.mon.stop_watch(self.dir)
        del self.mon
        print "Exiting monitoring"

class Processor(threading.Thread):
    def __init__(self, queue):
        threading.Thread.__init__(self)
        self.queue = queue
    def run(self):
        while True:
            url = self.queue.get()
            self.process_file(url)
            self.queue.task_done()
    def process_file(self, url):
        print "Processing file:", url

queue = Queue.Queue()
t = Processor(queue)
t.daemon = True
t.start()

monitor = MonitorThread(queue)
monitor.daemon = True
monitor.start()

try:
    while True: time.sleep(100)
except (KeyboardInterrupt, SystemExit):
    print "INTERRUPTED"

print "Main thread ends here"