Use Python to monitor file content changes code

This article mainly introduces the code for using Python to monitor file content changes. It has a certain reference value. Now I share it with you. Friends in need can refer to it.

There are two main types of file monitoring in python. There are two libraries, one is pyinotify and the other is watchdog. pyinotify relies on inotify on the Linux platform. Today we will discuss pyinotify.

Use seek to monitor file content and print out the changed content:

#/usr/bin/env python
#-*- coding=utf-8 -*-
 
pos = 0
while True:
  con = open("a.txt")
  if pos != 0:
    con.seek(pos,0)
  while True:
  line = con.readline()
  if line.strip():
    print line.strip()
  pos = pos + len(line)
  if not line.strip():
    break
  con.close()

Use the tool pyinotify to monitor file content changes. When the file gradually becomes larger, you can easily complete the task:

#!/usr/bin/env python
#-*- coding=utf-8 -*-
import os
import datetime
import pyinotify
import logging
 
pos = 0
def printlog():
  global pos
  try:
    fd = open("log/a.txt")
  if pos != 0:
    fd.seek(pos,0)
  while True:
    line = fd.readline()
    if line.strip():
      print line.strip()
    pos = pos + len(line)
    if not line.strip():
    break
  fd.close()
  except Exception,e:
  print str(e)
 
class MyEventHandler(pyinotify.ProcessEvent):
  def process_IN_MODIFY(self,event):
    try:
    printlog()
  except Exception,e:
    print str(e)
 
def main():
  printlog()
  wm = pyinotify.WatchManager()
  wm.add_watch("log/a.txt",pyinotify.ALL_EVENTS,rec=True)
  eh = MyEventHandler()
  notifier = pyinotify.Notifier(wm,eh)
  notifier.loop()
if __name__ == "__main__":
  main()

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