How to poll a file in /sys
- by Bjoern
Hi, I am stuck reading a file in /sys/ which contains the light intensity in Lux of the ambient light sensor on my Nokia N900 phone.
See thread on talk.maemo.org here
I tried to use pyinotify to poll the file but this looks some kind of wrong to me since the file is alway "process_IN_OPEN", "process_IN_ACCESS" and "process_IN_CLOSE_NOWRITE"
I basically want to get the changes ASAP and if something changed trigger an event, execute a class...
Here's the code I tried, which works, but not as I expected (I was hoping for process_IN_MODIFY to be triggered):
#!/usr/bin/env python
# -*- coding: utf-8 -*-
#
import os, time, pyinotify
import pyinotify
ambient_sensor = '/sys/class/i2c-adapter/i2c-2/2-0029/lux'
wm = pyinotify.WatchManager() # Watch Manager
mask = pyinotify.ALL_EVENTS
def action(self, the_event):
value = open(the_event.pathname, 'r').read().strip()
return value
class EventHandler(pyinotify.ProcessEvent):
def process_IN_ACCESS(self, event):
print "ACCESS event:", action(self, event)
def process_IN_ATTRIB(self, event):
print "ATTRIB event:", action(self, event)
def process_IN_CLOSE_NOWRITE(self, event):
print "CLOSE_NOWRITE event:", action(self, event)
def process_IN_CLOSE_WRITE(self, event):
print "CLOSE_WRITE event:", action(self, event)
def process_IN_CREATE(self, event):
print "CREATE event:", action(self, event)
def process_IN_DELETE(self, event):
print "DELETE event:", action(self, event)
def process_IN_MODIFY(self, event):
print "MODIFY event:", action(self, event)
def process_IN_OPEN(self, event):
print "OPEN event:", action(self, event)
#log.setLevel(10)
notifier = pyinotify.ThreadedNotifier(wm, EventHandler())
notifier.start()
wdd = wm.add_watch(ambient_sensor, mask)
wdd
time.sleep(5)
notifier.stop()
Thanks for any hints, suggestions and examples
Kind regards
Bjoern
