python fanotify 与 inotify

fanotify的API文档：http://man7.org/linux/man-pages/man7/fanotify.7.html
python fanotify代码样例：

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

import os
import fanotify
import select

class file_notifer(object):
    def __init__(self, path):
        self.notifer_fd = fanotify.Init(
            fanotify.FAN_CLASS_NOTIF, #接受event的优先级,系统发出event后,根据优先级,优先级最高的,最先接到
            os.O_RDWR | os.O_LARGEFILE # flag os.O_RDWR 文件描述符self.notifer_fd以什么样的权限打开
        )
        print "notifer fd is %s " %(self.notifer_fd)
        fanotify.Mark(
            self.notifer_fd, # fanotify.Init返回的
            fanotify.FAN_MARK_ADD, #对监听的文件的mark进行修改,可以是(ADD)添加,REMOVE(删除)等等
            fanotify.FAN_ACCESS, #监听的事件
             -1,
             path #监听的文件路径
        )

    def start_notifer(self):
        while True:
            r, w, e = select.select([self.notifer_fd], [], []) #用select去监听event的发生
            buf = os.read(self.notifer_fd, 4096) #关于os.read是否阻塞，其实是看读取的fd的类型的
            while fanotify.EventOk(buf): #如果buf中有event
                buf, event = fanotify.EventNext(buf) #读出 event
                print "event.mask: ", event.mask
                print "file modified %s" %(os.readlink("/proc/self/fd/%d" %event.fd))
                if event.mask & fanotify.FAN_MODIFY:
                    print "file modified %s" %(os.readlink("/proc/self/fd/%d" %fanotify_envent.fd))

if __name__ == "__main__":
#    notifer = file_notifer("/home/xxx/work/test/fanotify_sourcelist.py")
    notifer = file_notifer("/var/lib/apt/periodic/update-success-stamp")
    #notifer = file_notifer("/var/lib/apt/lists/test")
    notifer.start_notifer()

测试发现一个问题，对于ubuntu下/var/lib/apt/periodic/update-success-stamp文件，不管怎么操作，都没有产生event，但是对于个人手动创建的文件，fanotify是可以监测到事件的，待进一步研究。

inotify的API文档：http://man7.org/linux/man-pages/man7/inotify.7@@man-pages.html
python inotify代码样例

#!/usr/bin/env python
# encoding:utf-8
import os
from  pyinotify import  WatchManager, Notifier, \
ProcessEvent,IN_DELETE, IN_CREATE,IN_MODIFY, IN_ACCESS, IN_ATTRIB

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

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

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

    def process_IN_ACCESS(self, event):
        print "Access file: %s " % os.path.join(event.path, event.name)

    def process_IN_ATTRIB(self, event):
        print "Access file: %s " % os.path.join(event.path, event.name)

def FSMonitor(path='.'):
    wm = WatchManager()
    mask = IN_DELETE | IN_CREATE |IN_MODIFY |IN_ACCESS |IN_ATTRIB
    notifier = Notifier(wm, EventHandler())
    wm.add_watch(path, mask,rec=True) 
    print 'now starting monitor %s'%(path)
    while True:
        try:
            notifier.process_events() #绑定处理event方法
            if notifier.check_events(): #检查是否有有可读取的新event
                notifier.read_events() #读取event，交给EventHandler处理
        except KeyboardInterrupt:
            notifier.stop()
            break

if __name__ == "__main__":
    FSMonitor("/var/lib/apt/periodic/update-success-stamp")
#    FSMonitor("/home/xxx/work/test")
#     FSMonitor("/var/lib/apt/lists")

需要说明的是：按照目前个人理解，EventHandler类必须继承_ProcessEvent类，然后在类里面重写对应event的处理方法。_ProcessEvent源码如下：

class _ProcessEvent:
    """
    Abstract processing event class.
    """
    def __call__(self, event):
        """
        To behave like a functor the object must be callable.
        This method is a dispatch method. Its lookup order is:
          1. process_MASKNAME method
          2. process_FAMILY_NAME method
          3. otherwise calls process_default

        @param event: Event to be processed.
        @type event: Event object
        @return: By convention when used from the ProcessEvent class:
                 - Returning False or None (default value) means keep on
                 executing next chained functors (see chain.py example).
                 - Returning True instead means do not execute next
                   processing functions.
        @rtype: bool
        @raise ProcessEventError: Event object undispatchable,
                                  unknown event.
        """
        stripped_mask = event.mask - (event.mask & IN_ISDIR)
        maskname = EventsCodes.ALL_VALUES.get(stripped_mask)
        if maskname is None:
            raise ProcessEventError("Unknown mask 0x%08x" % stripped_mask)

        # 1- look for process_MASKNAME
        meth = getattr(self, 'process_' + maskname, None)
        if meth is not None:
            return meth(event)
        # 2- look for process_FAMILY_NAME
        meth = getattr(self, 'process_IN_' + maskname.split('_')[1], None) #匹配，处理对应的event
        if meth is not None:
            return meth(event)
        # 3- default call method process_default
        return self.process_default(event)