#!/usr/bin/env python
# -*- coding: Windows-1251 -*-
'''
File: tail-f.py
Call 'tail -f' for specified file and restarts when file's inode changed
'''
import os
import subprocess
import time
__author__ = 'Denis Barmenkov <denis.barmenkov@gmail.com>'
__source__ = 'http://code.activestate.com/recipes/577398/'
SLEEP_TIME = 1.0 # seconds
DELIM_LINE = '=' * 65
TAIL_PID = None
def get_inode(filename):
'''get inode for file'''
if not os.path.exists(filename):
return None
else:
return os.stat(filename)[1]
def kill_tail(pid):
'''kill tail on specified PID'''
if pid:
os.system('kill -9 %d' % pid)
def run_tail(filename):
'''run tail -f on file, returns tails's PID'''
if not os.path.exists(filename):
return None
process = subprocess.Popen(['tail', '-f', filename], bufsize=1)
return process.pid
def monitor_file(filename):
'''main monitor function'''
global TAIL_PID
inode = None
while 1:
inode_new = get_inode(filename)
if inode_new != inode:
kill_tail(TAIL_PID)
print DELIM_LINE
print 'restarted: tail -f %s' % filename
print DELIM_LINE
TAIL_PID = run_tail(filename)
inode = inode_new
else:
time.sleep(SLEEP_TIME)
def break_handler(signum, frame):
'''basic interrupt handling'''
kill_tail(TAIL_PID)
print
print DELIM_LINE
print 'Interrupted by signal %r' % signum
sys.exit(0)
if __name__ == '__main__':
import sys
import signal
for sig_name in 'SIGABRT SIGBREAK SIGILL SIGINT SIGTERM'.split():
if not hasattr(signal, sig_name):
continue
sig_id = getattr(signal, sig_name)
signal.signal(sig_id, break_handler)
monitor_file(sys.argv[1])
Diff to Previous Revision
--- revision 2 2010-09-21 07:36:06
+++ revision 3 2010-09-21 07:37:38
@@ -56,6 +56,7 @@
def break_handler(signum, frame):
'''basic interrupt handling'''
kill_tail(TAIL_PID)
+ print
print DELIM_LINE
print 'Interrupted by signal %r' % signum
sys.exit(0)
