Source code for hupper.polling
import os
import threading
import time
from .interfaces import IFileMonitor
[docs]
class PollingFileMonitor(threading.Thread, IFileMonitor):
"""
An :class:`hupper.interfaces.IFileMonitor` that stats the files
at periodic intervals.
``callback`` is a callable that accepts a path to a changed file.
``interval`` is a value in seconds between scans of the files on disk.
Do not set this too low or it will eat your CPU and kill your drive.
"""
def __init__(self, callback, interval=1, **kw):
super(PollingFileMonitor, self).__init__()
self.callback = callback
self.poll_interval = interval
self.paths = set()
self.mtimes = {}
self.lock = threading.Lock()
self.enabled = True
def add_path(self, path):
with self.lock:
self.paths.add(path)
def run(self):
while self.enabled:
with self.lock:
paths = list(self.paths)
self.check_reload(paths)
time.sleep(self.poll_interval)
def stop(self):
self.enabled = False
def check_reload(self, paths):
changes = set()
for path in paths:
mtime = get_mtime(path)
if path not in self.mtimes:
self.mtimes[path] = mtime
elif self.mtimes[path] < mtime:
self.mtimes[path] = mtime
changes.add(path)
for path in sorted(changes):
self.callback(path)
def get_mtime(path):
try:
stat = os.stat(path)
if stat:
return stat.st_mtime
except OSError: # pragma: no cover
pass
return 0