monitor.py

#! /usr/bin/env python

# Based on the Notifier example from tutorial
# See: http://trac.dbzteam.org/pyinotify/wiki/Tutorial

import optparse as op
import Queue
import subprocess as sp
import time

import pyinotify

__usage__ = "%prog [OPTIONS] DIR1 [DIR2 ...]"

class EventHandler(pyinotify.ProcessEvent):
    def __init__(self, q):
        self.q = q

    def process_default(self, event):
        if event.name.startswith("."):
            return
        self.q.put(event.pathname)

def run(opts, args, wm, notices):
    mask = pyinotify.IN_DELETE | pyinotify.IN_CREATE | pyinotify.IN_MODIFY
    for a in args:
        wm.add_watch(a, mask, rec=True)

    when = None
    while True:
        try:
            path = notices.get(timeout=1)
        except Queue.Empty:
            path = None
        if path is not None:
            print "=> %s" % path
            when = time.time()
        if when and time.time() - when > opts.wait:
            print "Executing..."
            sp.check_call(opts.command, shell=True)
            when = None

def options():
    return [
        op.make_option("-c", dest="command", default=None,
            help = "A command to execute."),
        op.make_option("-w", dest="wait", default=1, type="int",
            help = "Number of seconds to wait before executing."),
    ]

def main():
    parser = op.OptionParser(usage=__usage__, option_list=options())
    opts, args = parser.parse_args()

    if not len(args):
        args = ["."]

    notices = Queue.Queue()
    wm = pyinotify.WatchManager()
    handler = EventHandler(notices)
    notifier = pyinotify.ThreadedNotifier(wm, handler)
    notifier.start()
   
    try:
        run(opts, args, wm, notices)
    except KeyboardInterrupt:
        pass
    finally:
        notifier.stop()

if __name__ == '__main__':
    main()