Using inotify to watch for directory changes from Python

An inotify project is now available on PyPI. More documentation is available at the project homepage: PyInotify

Though the inotify functionality is uncomplicated to implement in C, it’s stupidly simple to implement in Python using this library.

To install:

$ sudo pip install inotify

This is the principal logic of the example provided in the project documentation:

i = inotify.adapters.Inotify()

i.add_watch('/tmp')

for event in i.event_gen():
    if event is not None:
        (header, type_names, watch_path, filename) = event

        _LOGGER.info("WD=(%d) MASK=(%d) COOKIE=(%d) LEN=(%d) MASK->NAMES=%s "
                     "WATCH-PATH=[%s] FILENAME=[%s]", 
                     header.wd, header.mask, header.cookie, header.len, type_names, 
                     watch_path, filename)

We ran the following operations on /tmp:

$ touch /tmp/aa
$ rm /tmp/aa
$ mkdir /tmp/dir1
$ rmdir /tmp/dir1

This was the corresponding output of the inotify process:

2015-04-24 05:02:06,667 - __main__ - INFO - WD=(1) MASK=(256) COOKIE=(0) LEN=(16) MASK->NAMES=['IN_CREATE'] FILENAME=[aa]
2015-04-24 05:02:06,667 - __main__ - INFO - WD=(1) MASK=(32) COOKIE=(0) LEN=(16) MASK->NAMES=['IN_OPEN'] FILENAME=[aa]
2015-04-24 05:02:06,667 - __main__ - INFO - WD=(1) MASK=(4) COOKIE=(0) LEN=(16) MASK->NAMES=['IN_ATTRIB'] FILENAME=[aa]
2015-04-24 05:02:06,667 - __main__ - INFO - WD=(1) MASK=(8) COOKIE=(0) LEN=(16) MASK->NAMES=['IN_CLOSE_WRITE'] FILENAME=[aa]
2015-04-24 05:02:17,412 - __main__ - INFO - WD=(1) MASK=(512) COOKIE=(0) LEN=(16) MASK->NAMES=['IN_DELETE'] FILENAME=[aa]
2015-04-24 05:02:22,884 - __main__ - INFO - WD=(1) MASK=(1073742080) COOKIE=(0) LEN=(16) MASK->NAMES=['IN_ISDIR', 'IN_CREATE'] FILENAME=[dir1]
2015-04-24 05:02:25,948 - __main__ - INFO - WD=(1) MASK=(1073742336) COOKIE=(0) LEN=(16) MASK->NAMES=['IN_ISDIR', 'IN_DELETE'] FILENAME=[dir1]

Lastly, this library also provides the ability to recursively watch a given directory. Just use the inotify.adapters.InotifyTree class instead of inotify.adapters.Inotify, and pass a path.

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