#!/usr/bin/python
# 
# Restarts NM if NM does not respond to periodic probes.
#
# Faiyaz Ahmed <faiyaza@cs.princeton.edu>
# Copyright (C) 2006 The Trustees of Princeton University
#
# $Id: nm_mom.py,v 1.2 2006/08/17 20:12:09 faiyaza Exp $
# 

import syslog
import os
import sys
import time

import socket
import xmlrpclib
import bwlimit

from sets import Set

# Utility functions
from pl_mom import *


def restartNM():
	try:
		pid = os.fork()
                if pid == 0:
			bwlimit.run("/etc/init.d/pl_nm stop")
			time.sleep(10)
			try:
				nmpid = bwlimit.run("/bin/ps -e -o pid,cmd | grep nm.py")[0].split(" ")[0]
				os.kill(int(nmpid), 9)
				time.sleep(3)
				print "NM  %s forcefully killed." %nmpid
			except:
				print "NM %s killed." %nmpid
			bwlimit.run("/etc/init.d/pl_nm restart")
			print "NM restarted."
                	os._exit(0)
                else:
                        os.waitpid(pid,0)
        except Exception, err:
                print "Warning: Exception received while restarting NM:  %s" % err


def main():
        syslog.openlog("nm_mom")
        sys.stdout = sys.stderr = Logger()
	
	nm = NM()
	last_maxrate = 0 
	try:
		# Query something.  If it doesnt come back...
                vals = nm.query("pl_netflow", [('nm_net_max_rate', last_maxrate)])

        except Exception, err:
                print "Warning: Exception received while querying NM:", err
		restartNM()

if __name__ == '__main__':
    main()