[python]文件系统监控

Pyinotify是一个Python模块，用来监测文件系统的变化。 Pyinotify依赖于Linux内核的功能—inotify（内核2.6.13合并）。 inotify的是一个事件驱动的通知器，其通知接口通过三个系统调用从内核空间到用户空间。pyinotify结合这些系统调用，并提供一个顶级的抽象和一个通用的方式来处理这些功能。

• pyinotify 说百了就是通过 调用系统的inotify来实现通知的
• inotify 既可以监视文件，也可以监视目录
• Inotify 使用系统调用而非 SIGIO 来通知文件系统事件。

Inotify 可以监视的文件系统事件包括：

Event Name	Is an Event	Description
IN_ACCESS	Yes	file was accessed.
IN_ATTRIB	Yes	metadata changed.
IN_CLOSE_NOWRITE	Yes	unwrittable file was closed.
IN_CLOSE_WRITE	Yes	writtable file was closed.
IN_CREATE	Yes	file/dir was created in watched directory.
IN_DELETE	Yes	file/dir was deleted in watched directory.
IN_DELETE_SELF	Yes	自删除，即一个可执行文件在执行时删除自己
IN_DONT_FOLLOW	No	don’t follow a symlink (lk 2.6.15).
IN_IGNORED	Yes	raised on watched item removing. Probably useless for you, prefer instead IN_DELETE*.
IN_ISDIR	No	event occurred against directory. It is always piggybacked to an event. The Event structure automatically provide this information (via .is_dir)
IN_MASK_ADD	No	to update a mask without overwriting the previous value (lk 2.6.14). Useful when updating a watch.
IN_MODIFY	Yes	file was modified.
IN_MOVE_SELF	Yes	自移动，即一个可执行文件在执行时移动自己
IN_MOVED_FROM	Yes	file/dir in a watched dir was moved from X. Can trace the full move of an item when IN_MOVED_TO is available too, in this case if the moved item is itself watched, its path will be updated (see IN_MOVE_SELF).
IN_MOVED_TO	Yes	file/dir was moved to Y in a watched dir (see IN_MOVE_FROM).
IN_ONLYDIR	No	only watch the path if it is a directory (lk 2.6.15). Usable when calling .add_watch.
IN_OPEN	Yes	file was opened.
IN_Q_OVERFLOW	Yes	event queued overflowed. This event doesn’t belongs to any particular watch.
IN_UNMOUNT	Yes	宿主文件系统被 umount

通过pyinotify来实现对文件系统的监控非常简单

#!/usr/bin/env python
# encoding:utf-8

import os
from  pyinotify import  WatchManager, Notifier, \
ProcessEvent,IN_DELETE, IN_CREATE,IN_MODIFY

class EventHandler(ProcessEvent):
   """事件处理"""
   defprocess_IN_CREATE(self, event):
       print  "Create file: %s "  %  os.path.join(event.path,event.name)

   defprocess_IN_DELETE(self, event):
       print  "Delete file: %s "  %  os.path.join(event.path,event.name)

   defprocess_IN_MODIFY(self, event):
           print   "Modify file: %s " %   os.path.join(event.path,event.name)

def FSMonitor(path='.'):
       wm= WatchManager()
       mask= IN_DELETE | IN_CREATE |IN_MODIFY
       notifier= Notifier(wm, EventHandler())
       wm.add_watch(path, mask,rec=True)
       print'now starting monitor %s'%(path)
       whileTrue:
               try:
                       notifier.process_events()
                       if notifier.check_events():
                               notifier.read_events()
               except KeyboardInterrupt:
                       notifier.stop()
                       break

if __name__ =="__main__":
   FSMonitor()

参考资料：
http://pyinotify.sourceforge.net/