I have been working with pyinotify and I am having issues with it where after multiple changes to a folder it simply stops receiving notifications. I have a feeling it is something to do with the the fact that two threads are running; namely the notifier thread and the wxpython thread.
The purpose of the app is to essentially load a picture to the screen when it detects an ip connection, monitor a folder for the file 'Checklist' and based on that file do some processing i.e move files around.
It works intermittently but being a python newbie Im not exactly sure what the issue might be as I have basically taken the threaded example and worked around it. Sometimes, it only gets one notification and stops receiving file change notifications.
Additionally, if I restart the linux box and try again, it works for a good number of file changes and then stops receiving notifications again which makes me think that perhaps its not releasing the watches properly?
Any help would be greatly appreciated as well as optimizations and improvements are very welcome. I'm sure I could learn a lot from the feedback. The code is below
import pyinotify
import os.path
import shutil
import errno
import subprocess
import logging
import wx
import time
import signal
import sys
#update CHECKLIST name
CHECKLIST = 'Checklist' #this must exist in the update archive
#static values
DIR_UPDATE = 'd'
FILE_UPDATE = 'f'
PING_IP = ' localhost' # change in production
#paths
WATCH_PATH = '/home/test'
LOG_PATH = '/home/test/update.log'
CONNECTED_IMG = 'update.jpg'
UPDATING_IMG = 'updating.png'
#msgs
UPDATEFOUND_MSG = ' Update Found '
UPDATEUNZIPPEDSTART_MSG = ' Update unzipping '
UPDATEUNZIPPED_MSG = ' Update unzipped '
UPDATEFILE_MSG = ' Update file '
UPDATEFILEMSG_CONT = ' moved into path '
REMOVEFILEMSG_CONT = ' removed from update folder '
UPDATECOMPLETE_CONT = ' Update complete'
ROADANGELRESTART_MSG = ' Update restarting app '
DIRCREATED_MSG = ' Directory created at path '
#errors
UPDATEFAILED_MSG = ' Update process failed on '
BADLYFORMED_MSG = ' Badly formed src/dest combination '
UPDATESRCUNAVAILABLE = ' Invalid update file specified '
UPDATEDESTUNAVAILABLE = ' Invalid update destination specified '
INVALIDUPDATEFORMAT = ' Invalid format string '
#on startup create the watchfolder if it doesnt exist
WM = pyinotify.WatchManager() # Watch Manager
WM_MASK = pyinotify.IN_CLOSE_WRITE # watched events
#setup logger
LOGGER = logging.getLogger('Updater')
LOG_HANDLE = logging.FileHandler(LOG_PATH)
FORMATTER = logging.Formatter('%(asctime)s %(levelname)s %(message)s')
LOG_HANDLE.setFormatter(FORMATTER)
LOGGER.addHandler(LOG_HANDLE)
LOGGER.setLevel(logging.INFO)
#Global values used primarily in the main function loop
HANDLER = None
NOTIFIER = None
WDD = None
UPDATE_UI = None
WINDOW = None
CURR_IMG = None
LAST_CURRIMG = None
class EventHandler(pyinotify.ProcessEvent):
VERBOSE = False
""" Main class to monitor file events and process accordingly"""
def process_IN_CLOSE_WRITE(self, event):
""" Only executes when a Checklist has finished being written to"""
path = event.pathname
print 'evt'
#look for the update_ready file before processing
if (os.path.basename(path) == 'Checklist'):
EventHandler.parse_updates(WATCH_PATH)
global CURR_IMG
CURR_IMG = os.path.join(WATCH_PATH, UPDATING_IMG)
show_window()
print 'update completed'
time.sleep(1000)
@classmethod
def parse_updates(cls, path):
""" parses update files """
#handle errors for opening the file
file_path = os.path.join(path, CHECKLIST)
print file_path
files = open(file_path)
#handle errors for malformed tuples-done
#handle errors for unavailable files-done
#handle errors for unavailable dests-done #created automatically
#handle permission errors
for line in files:
#remove linebreaks etc and ensure its not empty
if line.strip():
array = line.split('=')
length = len(array)
if length == 3:
EventHandler.process_line(path, array)
else:
if length > 0:
EventHandler.print_bad_msg(array[0])
else:
EventHandler.print_bad_msg()
print 'removing ', file_path
os.remove(file_path) #remove the checklist file
@classmethod
def mkdir(cls, path):
""" makes a directory from a path"""
try:
os.mkdir(path)
print DIRCREATED_MSG, path
except OSError, err:
print err
if err.errno != errno.EEXIST: #thrown when the dir already exists
return False
@classmethod
def move_file(cls, src, dest):
""" moves a file from src to dest and remove after
expects that the dest already exists at this point
otherwise ignores the move"""
#print 'moving from', src, 'to ', dest
if os.path.isfile(dest):
shutil.copy2(src, dest)
else:
print UPDATEDESTUNAVAILABLE
#remove the src file when done
os.remove(src)
@classmethod
def process_line(cls, path, array):
""" process a line from the checklist"""
#remove newlines etc
update_file = array[0].strip()
update_src = os.path.join(path, update_file)
update_dest = array[1].strip()
update_type = array[2].strip()
#ensure we have valid values in all three fields
if update_file and update_dest and update_type:
#ensure the src file exists
if os.path.isfile(update_src):
#check if destination is directory and
#copy the file into the directory
if update_type == DIR_UPDATE:
EventHandler.mkdir(update_dest)
dest = os.path.join(update_dest, update_file)
EventHandler.move_file(update_src, dest)
else:
EventHandler.move_file(update_src, update_dest)
else:
print UPDATESRCUNAVAILABLE
else:
print INVALIDUPDATEFORMAT
@classmethod
def print_bad_msg(cls, msg = ''):
""" print a badly formed message with optional value"""
if msg:
print BADLYFORMED_MSG, msg
else:
print BADLYFORMED_MSG
class UpdateFrame(wx.Frame):
""" Displays update images to screen"""
def __init__(self, path):
wx.Frame.__init__(self, None, wx.ID_ANY)
image_file = path
image = wx.Bitmap(image_file)
image_size = image.GetSize()
# set the frame size to fit the screen size
self.SetClientSize(wx.DisplaySize())
# bitmap's upper left corner is in frame position (x, y)
# by default pos=(0, 0)
wx.StaticBitmap(self, wx.ID_ANY, image, size = image_size)
# the parent is the frame
self.SetTitle('Update Mode')
def ping_ip():
""" ping once to establish connection """
ret = subprocess.call("ping -c 1 %s" % PING_IP,
shell=True,
stdout=open('/dev/null', 'w'),
stderr=subprocess.STDOUT)
if ret == 0:
return True
else:
return False
def show_window():
""" update screen window when currimage changes is set """
global UPDATE_UI
global WINDOW
global CURR_IMG
global LAST_CURRIMG
if LAST_CURRIMG != CURR_IMG:
if not UPDATE_UI:
UPDATE_UI = wx.App()
if not WINDOW:
WINDOW = UpdateFrame(CURR_IMG)
UPDATE_UI.ExitMainLoop()
while(UPDATE_UI.IsMainLoopRunning()):
pass
WINDOW.Destroy()
WINDOW = UpdateFrame(CURR_IMG)
WINDOW.Show(True)
UPDATE_UI.MainLoop()
LAST_CURRIMG = CURR_IMG
print 'changed'
def in_updatemode():
return ping_ip()
while True:
try:
if not in_updatemode():
print 'waiting for connect'
time.sleep(3)
if NOTIFIER:
NOTIFIER.stop()
else:
if not HANDLER:
HANDLER = EventHandler()
if not NOTIFIER:
NOTIFIER = pyinotify.ThreadedNotifier(WM, HANDLER)
NOTIFIER.start()
if not WDD:
WDD = WM.add_watch(WATCH_PATH, WM_MASK, rec=True,quiet=False)
# ip is active so show the image and start the notifier
# state = ip active
CURR_IMG = os.path.join(WATCH_PATH, CONNECTED_IMG)
show_window()
print 'here'
except KeyboardInterrupt:
print 'out'
NOTIFIER.stop()
break
