Surveillance d'un répertoire en python
**************************************

il est parfois utile de pouvoir surveiller un répertoire en temps réel pour
générer des actions par exemple.

Installation
------------

.. code-block:: bash

    pip install watchdog

Utilisation basique
-------------------

Objectif surveiller le répertoire sylob

test_watchdog.py

.. code-block:: python

    import sys
    import time
    import logging
    from watchdog.observers import Observer
    from watchdog.events import LoggingEventHandler

    if __name__ == "__main__":
        logging.basicConfig(level=logging.INFO,
                            format='%(asctime)s - %(message)s',
                            datefmt='%Y-%m-%d %H:%M:%S')
        path = sys.argv[1] if len(sys.argv) > 1 else '.'
        event_handler = LoggingEventHandler()
        observer = Observer()
        observer.schedule(event_handler, path, recursive=True)
        observer.start()
        try:
            while True:
                time.sleep(1)
        except KeyboardInterrupt:
            observer.stop()
        observer.join()

utilisation        

.. code-block:: bash

    >> python test_watchdog.py sylob/
    2014-06-19 15:09:23 - Deleted file: C:\Users\f.aoustin\Desktop\sylob\1.txt
    2014-06-19 15:09:40 - Created file: C:\Users\f.aoustin\Desktop\sylob\ServiceInformatique.docx
    2014-06-19 15:09:40 - Modified file: C:\Users\f.aoustin\Desktop\sylob\ServiceInformatique.docx
    2014-06-19 15:09:47 - Moved file: from C:\Users\f.aoustin\Desktop\sylob\ServiceInformatique.docx to C:\Users\f.aoustin\Desktop\sylob\tutu.docx
    2014-06-19 15:09:47 - Modified file: C:\Users\f.aoustin\Desktop\sylob\tutu.docx
    
    
Utilisation en ligne de commande
--------------------------------

.. code-block:: bash

    watchmedo log --patterns="*.py;*.txt" --ignore-directories --recursive .
    
lancer une commande à chaque évènement    

    watchmedo log --patterns="*.py;*.txt" --recursive --command='echo "${watch_src_path}"' .
    
Utilisation avancée
-------------------

Il est possible de créer ses propres handlers

.. code-block:: python

    import sys
    import time
    import logging
    import time  
    from watchdog.observers import Observer  
    from watchdog.events import PatternMatchingEventHandler  

    class MyHandler(PatternMatchingEventHandler):
        patterns = ["*.xml", "*.lxml"]

        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 degug

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

        def on_created(self, event):
            self.process(event)
            
    if __name__ == '__main__':
        args = sys.argv[1:]
        observer = Observer()
        observer.schedule(MyHandler(), path=args[0] if args else '.')
        observer.start()

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

        observer.join()

utilisation        

.. code-block:: bash

    >> python test_watchdog.py sylob/
    C:\Users\f.aoustin\Desktop\sylob\log.xml modified
    C:\Users\f.aoustin\Desktop\sylob\log.xml modified
    C:\Users\f.aoustin\Desktop\sylob\log.xml modified
    
.. note::

    il existe d'autres action comme on_moved, on_deleted