基于python的文件监控watchdog

　　实时监控第三方库watchdog，其原理通过操作系统的时间触发的，不需要循环和等待

使用场景：

　　1.监控文件系统中文件或目录的增删改情况

　　2.当特定的文件被创建，删除，修改，移动时执行相应的任务

1. 安装

pip install watchdog

示例：

1)监控文件内容变更触发响应操作

import re
import os
import logging
from watchdog.events import FileSystemEventHandler
from watchdog.observers import Observer

logging.basicConfig(level=logging.INFO, format='%(asctime)s - %(name)s - %(levelname)s - %(message)s')

LUA_FILE_NAME = 'version_info.lua'  #Lua版本文件
WHITELIST_FILE_NAME = 'whitelist.txt'  # 白名单文件

class FileMonitorHandler(FileSystemEventHandler):
    def __init__(self, **kwargs):
        super(FileMonitorHandler, self).__init__(**kwargs)
        # 监控目录 目录下面以device_id为目录存放各自的图片
        self._watch_path = game_path

    # 重写文件改变函数，文件改变都会触发文件夹变化
    def on_modified(self, event):
        if not event.is_directory:  # 文件改变都会触发文件夹变化
            file_path = event.src_path
            logging.info("file changed: %s " % file_path)
            file_name = os.path.split(file_path)[-1]
            # 白名单或者配置文件修改，则触发事件
            if file_name == LUA_FILE_NAME:  # lua文件发生变化
                # 验证该目录下是否存在白名单文件
                whitelist_file, is_exists = check_file_exists(file_path, WHITELIST_FILE_NAME)
                if not is_exists:  # 不存在白名单，则不进行修改操作
                    logging.info(f'{whitelist_file} not exists')
                else:
                    # 读取文件进行替换操作
                    whitelist_handler(file_path, whitelist_file)
            elif file_name == WHITELIST_FILE_NAME:  # 白名单文件发生变化
                # 验证配置文件是否存在
                lua_file, is_exists = check_file_exists(file_path, LUA_FILE_NAME)
                if not is_exists:  # 不存在Lua文件
                    logging.info(f'{lua_file} not exists')
                else:
                    whitelist_handler(lua_file, file_path)
        else:
            logging.info('Director changed')

    def on_created(self, event):
        pass

def check_file_exists(path, file_name):
    """
    验证文件的存在性
    """
    file_path = os.path.join(os.path.dirname(path), file_name)
    is_exists = os.path.isfile(file_path)
    return file_path, is_exists

def replace_content(lua_file, new_str):
    with open(lua_file, 'r', encoding='utf-8') as f1, open("%s.bak" % lua_file, "w", encoding='utf-8') as f2:
        old_content = f1.read()
        if 'testId' in old_content:
            # 进行正则匹配
            pattern = re.compile(r'testId = "(.*?)"', re.M | re.S)
            new_content = re.sub(pattern, f'testId = "{new_str}"', old_content)
            logging.info('Old content:%s' % old_content)
            logging.info('New content:%s' % new_content)
            f2.write(new_content)

    os.remove(lua_file)
    os.rename("%s.bak" % lua_file, lua_file)

def whitelist_handler(lua_file, whitelist_file):
    """
    白名单处理
    """
    with open(whitelist_file, 'r', encoding='utf-8') as f:
        whitelist_content = f.read().replace("\n", "")
    logging.info(f'Replace content: lua_file->{lua_file} whitelist content->{whitelist_content}')
    replace_content(lua_file, whitelist_content)

def main():
    event_handler = FileMonitorHandler()
    observer = Observer()
    observer.schedule(event_handler, path=game_path, recursive=True)  # recursive递归的
    observer.start()
    observer.join()

if __name__ == '__main__':
    global game_path
    game_path = '/test2/files'
    main()

2)项目文件变更触发Git提交(实时同步到代码仓库)

#!/usr/bin/python
# -*- coding: utf-8 -*-

import sys
import time
import ntpath
import os
import re
import platform

from subprocess import call
from shutil import copy
from watchdog.observers import Observer
from watchdog.events import FileSystemEventHandler

# git root path for files to push to remote
DIR_FOR_GIT = os.path.dirname(os.path.abspath(__file__))

# 执行需要监控的同步的文件
SYNC_FILE_LIST = [
    'Redis.md',
    'MySQL+Redis.md',
    'MySQL.md',
]

class FileChangeHandler(FileSystemEventHandler):
    def on_modified(self, event):
        # print('文件发生变化')
        src_path = event.src_path.replace('\\', '/')
        base_name = os.path.basename(src_path)
        # print('base_name:', base_name)
        if base_name in SYNC_FILE_LIST:
            # print('src_path:', src_path)
            os.chdir(DIR_FOR_GIT)
            git_add_cmd = "git add -A"
            git_commit_cmd = "git commit -m " + re.escape("Update " + base_name)
            if platform.system() == "Windows":
                git_commit_cmd = "git commit -m Update."
            git_pull_cmd = "git pull origin main"
            git_push_cmd = "git push origin main"
            call(
                git_add_cmd + "&&" +
                git_commit_cmd + "&&" +
                git_pull_cmd + "&&" +
                git_push_cmd,
                shell=True
            )

if __name__ == "__main__":
    observer = Observer()
    event_handler = FileChangeHandler()

    for file_path in SYNC_FILE_LIST:
        file_path = os.path.join(DIR_FOR_GIT, file_path)
        # print('当前文件路径', file_path)
        observer.schedule(event_handler, path=os.path.dirname(os.path.realpath(file_path)), recursive=False)

    observer.start()

    try:
        while True:
            time.sleep(10)
    except KeyboardInterrupt:
        # print('服务中断')
        observer.stop()
    observer.join()

添加对应的监控程序之后, 可以在windows上开机自启动

@echo off
pythonw E:\www\项目\file_sync.py
:: echo "hello,bat"

然后将bat文件以快捷方式发送到桌面, 然后将其拖入启动项目录

C:\Users\用户名\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Startup

　　

常见问题：

　　1. OSError: inotify watch limit reached 错误

在添加监控任务之后， 发现出现这个错误， 是因为已经达到了inotify监控的一个上限值

　　查看目前的上限值：

cat /proc/sys/fs/inotify/max_user_watches
 默认是8192

　　解决：

1）临时生效
echo 81920 > /proc/sys/fs/inotify/max_user_watches

2）永久
在 /etc/sysctl.conf 中添加一行：
fs.inotify.max_user_watches=99999999
修改后保存
 立即生效    sysctl -p