import os

import sys

import time

import signal

import threading

import atexit

from queue import Queue

_interval = 1.0

_times = {}

_files = []

_running = False

_queue = Queue()

_lock = threading.Lock()

def _restart(path):

_queue.put(True)

prefix = 'monitor (pid=%d):' % os.getpid()

# print('%s Change detected to \'%s\'.' % (prefix, path), file=sys.stderr)

# print('%s Triggering process restart.' % prefix, file=sys.stderr)

os.kill(os.getpid(), signal.SIGINT)

def _modified(path):

try:

# Check for when file last modified.

mtime = os.stat(path).st_mtime

if path not in _times:

_times[path] = mtime

# Force restart when modification time has changed, even

# if time now older, as that could indicate older file

# has been restored.

if mtime != _times[path]:

return True

except:

pass

return False

def _monitor():

while 1:

# Check modification times on files which have

# specifically been registered for monitoring.

for path in _files:

if _modified(path):

return _restart(path)

# Go to sleep for specified interval.

try:

return _queue.get(timeout=_interval)

except:

pass

_thread = threading.Thread(target=_monitor)

_thread.setDaemon(True)

def _exiting():

try:

_queue.put_nowait(True)

except:

pass

# _thread.join()

atexit.register(_exiting)

def track(path):

print(path)

if not path in _files:

_files.append(path)

def start(interval=1.0):

global _interval

_interval = interval

global _running

_lock.acquire()

if not _running:

prefix = 'monitor (pid=%d):' % os.getpid()

# print('%s Starting change monitor.' % prefix, file=sys.stderr)

_running = True

_thread.start()

_lock.release()