pyinotify: execute a command with args

this might be a dup but I couldn't find exactly what I was looking for. Feel free to link any previous answer.

I need to write a python script (bash also would be ok) that continuously watches a directory. When the content of this directory changes (because another program generates a new directory inside of it), I want to run automatically a command line that has the name of the newly created directory as an argument.

Example: I need to watch directory /home/tmp/: the actual content of the directory is:

$ ls /home/tmp
Patient     Patient2     Patient3

Suddenly, Patient4 dir arrives in /home/tmp. I want a code that runs automatically

$ my_command --target_dir /home/tmp/Patient4/

I hope I'm clear in explaining what I need. Thanks

Solution

The answer that i found works on Linux only, and it makes use of the pyinotify wrapper. below is the wroking code:

    class EventProcessor(pyinotify.ProcessEvent):
    _methods = ["IN_CREATE",
                # "IN_OPEN",
                # "IN_ACCESS",
                ]

def process_generator(cls, method):
    def _method_name(self, event):
        if event.maskname=="IN_CREATE|IN_ISDIR":
            print(f"Starting pipeline for {event.pathname}")
            os.system(f"clearlung --single --automatic --base_dir {event.pathname} --target_dir CT " + \
                    f"--model {MODEL} --subroi --output_dir {OUTPUT} --tag 0 --history_path {HISTORY}")
            pass

    _method_name.__name__ = "process_{}".format(method)
    setattr(cls, _method_name.__name__, _method_name)

for method in EventProcessor._methods:
    process_generator(EventProcessor, method)

class PathWatcher():
    """Class to watch for changes"""

    def __init__(self, path_to_watch) -> None:
        """Base constructor"""
        self.path = path_to_watch

        if not os.path.isdir(self.path):
            raise FileNotFoundError()
         
    def watch(self,):
        """Main method of the PathWatcher class"""
        print(f"Waiting for changes in {self.path}...")

        watch_manager = pyinotify.WatchManager()
        event_notifier = pyinotify.Notifier(watch_manager, EventProcessor())

        watch_this = os.path.abspath(self.path)
        watch_manager.add_watch(watch_this, pyinotify.ALL_EVENTS)
        event_notifier.loop()