Many times a file must be processed during its creation or modification. This can be done by following the changes in a specific directory. There are many ways in python to keep track of changes made to a directory. One such way is to use the watchdog module. As the name suggests, this module monitors the given directory and can notify if a file is created or modified.

Required Modules

• Guard Dog
  To install the watchdog, run this command in a terminal.

   pip install watchdog 

• logging
  It comes with Python, so no need install it externally.

Now let`s dive into the code that will log all the logged changes. This code will only log changes checked in to the current directory.

# import modules import sys import time import logging from watchdog.observers import Observer from watchdog.events import LoggingEventHandler    if __ name__ = = " __ main__ " :   # Set the format for logging information logging.basicConfig (level = logging.INFO, format = `% (asctime) s -% (message) s` , datefmt = `% Y-% m-% d% H:% M:% S` )   # Install format for displaying the path path = sys.argv [ 1 ] if len (sys.argv) & gt;  1 else `.`   # Initialize registration event handler event_handler = LoggingEventHandler ()   # Initialize Observer observer = Observer () observer.schedule (event_handler, path, recursive = True )   # Start observer observer.start () try : while True :   # Set stream timeout time.sleep ( 1 )   except KeyboardInterrupt: observer.stop () observer.join ()

Output:

The above code will log all changes registered to the directory. If you want to make changes while creating or modifying a file, you can do so using the following code.

# import time module, Observer, FileSystemEventHandler import time from watchdog.observers import Observer from watchdog.events import FileSystemEventHandler     class OnMyWatch: # Set directory to watch watchDirectory = "/ give / the / address / of / directory"   def __ init __ ( self ): self .observer = Observer ()      def run ( self ): event_handler = Handler ()   self . observer.schedule (event_handler, self . watchDirectory, recursive = True )   self . observer .start () try : while True : time.sleep ( 5 ) except :   self . observer.stop ()   print ( "Observer Stopped" )      self . observer.join ()     class Handler (FileSystemEventHandler):     @ staticmethod def on_any_event (event): if event.is_directory:   return None    elif event.event_type = = `created` : # The event was created, you can process it now print ( "Watchdog received created event -% s." % event.src_path) elif event.event_type = = `modified` :  # The event has been changed, you can handle it now print ( " Watchdog received modified event -% s. " % event.src_path)     if __ name__ = = ` __main__` : watch = OnMyWatch () watch.run ()

Output: