watchfiles (https://github.com/samuelcolvin/watchfiles)是一个Python API和CLI，它使用了用Rust编写的Notify (https://github.com/notify-rs/notify)库。

rust实现目前(2022-10-09)支持:

Linux / Android: inotify macOS: FSEvents或kqueue，参见特性 Windows: ReadDirectoryChangesW FreeBSD / NetBSD / OpenBSD / DragonflyBSD: kqueue 所有平台:投票

可以在PyPI (https://pypi.org/project/watchfiles/)和conda-forge (https://github.com/conda-forge/watchfiles-feedstock)上获得二进制文件。

如果您想要一个多平台解决方案，那么请检查QFileSystemWatcher。 下面是一个示例代码(未消毒):

from PyQt4 import QtCore

@QtCore.pyqtSlot(str)
def directory_changed(path):
    print('Directory Changed!!!')

@QtCore.pyqtSlot(str)
def file_changed(path):
    print('File Changed!!!')

fs_watcher = QtCore.QFileSystemWatcher(['/path/to/files_1', '/path/to/files_2', '/path/to/files_3'])

fs_watcher.connect(fs_watcher, QtCore.SIGNAL('directoryChanged(QString)'), directory_changed)
fs_watcher.connect(fs_watcher, QtCore.SIGNAL('fileChanged(QString)'), file_changed)

为了用轮询和最小依赖来观察单个文件，下面是一个完整的例子，基于Deestan的回答(上面):

import os
import sys 
import time

class Watcher(object):
    running = True
    refresh_delay_secs = 1

    # Constructor
    def __init__(self, watch_file, call_func_on_change=None, *args, **kwargs):
        self._cached_stamp = 0
        self.filename = watch_file
        self.call_func_on_change = call_func_on_change
        self.args = args
        self.kwargs = kwargs

    # Look for changes
    def look(self):
        stamp = os.stat(self.filename).st_mtime
        if stamp != self._cached_stamp:
            self._cached_stamp = stamp
            # File has changed, so do something...
            print('File changed')
            if self.call_func_on_change is not None:
                self.call_func_on_change(*self.args, **self.kwargs)

    # Keep watching in a loop        
    def watch(self):
        while self.running: 
            try: 
                # Look for changes
                time.sleep(self.refresh_delay_secs) 
                self.look() 
            except KeyboardInterrupt: 
                print('\nDone') 
                break 
            except FileNotFoundError:
                # Action on file not found
                pass
            except: 
                print('Unhandled error: %s' % sys.exc_info()[0])

# Call this function each time a change happens
def custom_action(text):
    print(text)

watch_file = 'my_file.txt'

# watcher = Watcher(watch_file)  # simple
watcher = Watcher(watch_file, custom_action, text='yes, changed')  # also call custom action function
watcher.watch()  # start the watch going

最好和最简单的解决方案是使用pygtail: https://pypi.python.org/pypi/pygtail

from pygtail import Pygtail
import sys

while True:
    for line in Pygtail("some.log"):
        sys.stdout.write(line)

import inotify.adapters
from datetime import datetime


LOG_FILE='/var/log/mysql/server_audit.log'


def main():
    start_time = datetime.now()
    while True:
        i = inotify.adapters.Inotify()
        i.add_watch(LOG_FILE)
        for event in i.event_gen(yield_nones=False):
            break
        del i

        with open(LOG_FILE, 'r') as f:
            for line in f:
                entry = line.split(',')
                entry_time = datetime.strptime(entry[0],
                                               '%Y%m%d %H:%M:%S')
                if entry_time > start_time:
                    start_time = entry_time
                    print(entry)


if __name__ == '__main__':
    main()

似乎没有人张贴fswatch。它是一个跨平台的文件系统监视器。只要安装它，运行它，并按照提示。

我在python和golang程序中使用过它，它只是工作。