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https://github.com/gorakhargosh/watchdog

Python library and shell utilities to monitor filesystem events.
https://github.com/gorakhargosh/watchdog

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Python library and shell utilities to monitor filesystem events.

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Watchdog

========



|Build Status|

|CirrusCI Status|



Python API and shell utilities to monitor file system events.



Works on 3.8+.



Example API Usage

-----------------



A simple program that uses watchdog to monitor directories specified

as command-line arguments and logs events generated:



.. 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 '.'

        logging.info(f'start watching directory {path!r}')

        event_handler = LoggingEventHandler()

        observer = Observer()

        observer.schedule(event_handler, path, recursive=True)

        observer.start()

        try:

            while True:

                time.sleep(1)

        finally:

            observer.stop()

            observer.join()



Shell Utilities

---------------



Watchdog comes with an *optional* utility script called ``watchmedo``.

Please type ``watchmedo --help`` at the shell prompt to

know more about this tool.



Here is how you can log the current directory recursively

for events related only to ``*.py`` and ``*.txt`` files while

ignoring all directory events:



.. code-block:: bash



    watchmedo log \

        --patterns="*.py;*.txt" \

        --ignore-directories \

        --recursive \

        --verbose \

        .



You can use the ``shell-command`` subcommand to execute shell commands in

response to events:



.. code-block:: bash



    watchmedo shell-command \

        --patterns="*.py;*.txt" \

        --recursive \

        --command='echo "${watch_src_path}"' \

        .



Please see the help information for these commands by typing:



.. code-block:: bash



    watchmedo [command] --help



About ``watchmedo`` Tricks

~~~~~~~~~~~~~~~~~~~~~~~~~~



``watchmedo`` can read ``tricks.yaml`` files and execute tricks within them in

response to file system events. Tricks are actually event handlers that

subclass ``watchdog.tricks.Trick`` and are written by plugin authors. Trick

classes are augmented with a few additional features that regular event handlers

don't need.



An example ``tricks.yaml`` file:



.. code-block:: yaml



    tricks:

    - watchdog.tricks.LoggerTrick:

        patterns: ["*.py", "*.js"]

    - watchmedo_webtricks.GoogleClosureTrick:

        patterns: ['*.js']

        hash_names: true

        mappings_format: json                  # json|yaml|python

        mappings_module: app/javascript_mappings

        suffix: .min.js

        compilation_level: advanced            # simple|advanced

        source_directory: app/static/js/

        destination_directory: app/public/js/

        files:

          index-page:

          - app/static/js/vendor/jquery*.js

          - app/static/js/base.js

          - app/static/js/index-page.js

          about-page:

          - app/static/js/vendor/jquery*.js

          - app/static/js/base.js

          - app/static/js/about-page/**/*.js



The directory containing the ``tricks.yaml`` file will be monitored. Each trick

class is initialized with its corresponding keys in the ``tricks.yaml`` file as

arguments and events are fed to an instance of this class as they arrive.



Installation

------------

Install from PyPI using ``pip``:



.. code-block:: bash



    $ python -m pip install -U watchdog



    # or to install the watchmedo utility:

    $ python -m pip install -U "watchdog[watchmedo]"



Install from source:



.. code-block:: bash



    $ python -m pip install -e .



    # or to install the watchmedo utility:

    $ python -m pip install -e ".[watchmedo]"



Documentation

-------------



You can browse the latest release documentation_ online.



Contribute

----------



Fork the `repository`_ on GitHub and send a pull request, or file an issue

ticket at the `issue tracker`_. For general help and questions use

`stackoverflow`_ with tag `python-watchdog`.



Create and activate your virtual environment, then::



    python -m pip install pytest pytest-cov

    python -m pip install -e ".[watchmedo]"

    python -m pytest tests



If you are making a substantial change, add an entry to the "Unreleased" section

of the `changelog`_.



Supported Platforms

-------------------



* Linux 2.6 (inotify)

* macOS (FSEvents, kqueue)

* FreeBSD/BSD (kqueue)

* Windows (ReadDirectoryChangesW with I/O completion ports;

  ReadDirectoryChangesW worker threads)

* OS-independent (polling the disk for directory snapshots and comparing them

  periodically; slow and not recommended)



Note that when using watchdog with kqueue, you need the

number of file descriptors allowed to be opened by programs

running on your system to be increased to more than the

number of files that you will be monitoring. The easiest way

to do that is to edit your ``~/.profile`` file and add

a line similar to::



    ulimit -n 1024



This is an inherent problem with kqueue because it uses

file descriptors to monitor files. That plus the enormous

amount of bookkeeping that watchdog needs to do in order

to monitor file descriptors just makes this a painful way

to monitor files and directories. In essence, kqueue is

not a very scalable way to monitor a deeply nested

directory of files and directories with a large number of

files.



About using watchdog with editors like Vim

------------------------------------------



Vim does not modify files unless directed to do so.

It creates backup files and then swaps them in to replace

the files you are editing on the disk. This means that

if you use Vim to edit your files, the on-modified events

for those files will not be triggered by watchdog.

You may need to configure Vim appropriately to disable

this feature.



About using watchdog with CIFS

------------------------------



When you want to watch changes in CIFS, you need to explicitly tell watchdog to

use ``PollingObserver``, that is, instead of letting watchdog decide an

appropriate observer like in the example above, do::



    from watchdog.observers.polling import PollingObserver as Observer



Dependencies

------------



1. Python 3.8 or above.

2. XCode_ (only on macOS when installing from sources)

3. PyYAML_ (only for ``watchmedo``)



Licensing

---------



Watchdog is licensed under the terms of the `Apache License, version 2.0`_.



Copyright 2011 `Yesudeep Mangalapilly`_.



Copyright 2012 Google, Inc & contributors.



Project `source code`_ is available at Github. Please report bugs and file

enhancement requests at the `issue tracker`_.



Why Watchdog?

-------------



Too many people tried to do the same thing and none did what I needed Python

to do:



* pnotify_

* `unison fsmonitor`_

* fsmonitor_

* guard_

* pyinotify_

* `inotify-tools`_

* jnotify_

* treewatcher_

* `file.monitor`_

* pyfilesystem_



.. links:

.. _Yesudeep Mangalapilly: [email protected]

.. _source code: https://github.com/gorakhargosh/watchdog

.. _issue tracker: https://github.com/gorakhargosh/watchdog/issues

.. _Apache License, version 2.0: https://www.apache.org/licenses/LICENSE-2.0

.. _documentation: https://python-watchdog.readthedocs.io/

.. _stackoverflow: https://stackoverflow.com/questions/tagged/python-watchdog

.. _repository: https://github.com/gorakhargosh/watchdog

.. _issue tracker: https://github.com/gorakhargosh/watchdog/issues

.. _changelog: https://github.com/gorakhargosh/watchdog/blob/master/changelog.rst



.. _PyYAML: https://www.pyyaml.org/

.. _XCode: https://developer.apple.com/technologies/tools/xcode.html



.. _pnotify: http://mark.heily.com/pnotify

.. _unison fsmonitor: https://webdav.seas.upenn.edu/viewvc/unison/trunk/src/fsmonitor.py?view=markup&pathrev=471

.. _fsmonitor: https://github.com/shaurz/fsmonitor

.. _guard: https://github.com/guard/guard

.. _pyinotify: https://github.com/seb-m/pyinotify

.. _inotify-tools: https://github.com/rvoicilas/inotify-tools

.. _jnotify: http://jnotify.sourceforge.net/

.. _treewatcher: https://github.com/jbd/treewatcher

.. _file.monitor: https://github.com/pke/file.monitor

.. _pyfilesystem: https://github.com/PyFilesystem/pyfilesystem



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