PyGTK/GIO: monitor directory for changes recursively

Question

Take the following demo code (from the GIO answer to this question), which uses a GIO FileMonitor to monitor a directory for changes:

import gio

def directory_c         


        

Answer 1

I'm not sure if GIO allows you to have more than one monitor at once, but if it does there's no* reason you can't do something like this:

import gio
import os

def directory_changed(monitor, file1, file2, evt_type):
    if os.path.isdir(file2):    #maybe this needs to be file1?
        add_monitor(file2) 
    print "Changed:", file1, file2, evt_type

def add_monitor(dir):
    gfile = gio.File(dir)
    monitor = gfile.monitor_directory(gio.FILE_MONITOR_NONE, None)
    monitor.connect("changed", directory_changed) 

add_monitor('.')

import glib
ml = glib.MainLoop()
ml.run()

*when I say no reason, there's the possibility that this could become a resource hog, though with nearly zero knowledge about GIO I couldn't really say. It's also entirely possible to roll your own in Python with a few commands (os.listdir among others). It might look something like this

import time
import os

class Watcher(object):
    def __init__(self):
        self.dirs = []
        self.snapshots = {}

    def add_dir(self, dir):
        self.dirs.append(dir)

    def check_for_changes(self, dir):
        snapshot = self.snapshots.get(dir)
        curstate = os.listdir(dir)
        if not snapshot:
            self.snapshots[dir] = curstate
        else:
            if not snapshot == curstate:
                print 'Changes: ',
                for change in set(curstate).symmetric_difference(set(snapshot)):
                    if os.path.isdir(change):
                        print "isdir"
                        self.add_dir(change)
                    print change,

                self.snapshots[dir] = curstate
                print

    def mainloop(self):
        if len(self.dirs) < 1:
            print "ERROR: Please add a directory with add_dir()"
            return

        while True:
            for dir in self.dirs:
                self.check_for_changes(dir)
            time.sleep(4) # Don't want to be a resource hog

w = Watcher()
w.add_dir('.')


w.mainloop()

Answer 2

"Is there an easy way to make it recursive?"

I'm not aware of any "easy way" to achieve this. The underlying systems, such as inotify on Linux or kqueue on BSDs don't provide facilities to automatically add recursive watches. I'm also not aware of any library layering what you want atop GIO.

So you'll most likely have to build this yourself. As this can be a bit trick in some corner cases (e.g. mkdir -p foo/bar/baz) I would suggest looking at how pynotify implements its auto_add functionality (grep through the pynotify source) and porting that over to GIO.