#!/usr/bin/env python
#
# Nagios check to verify signal level of nanostation5
#
# Based on check_remoteneighbor
#
# By Richard van Mansom 
#

OK      = 15
WARNING = 10 
OFFSET  = -96

from collections import defaultdict
from pysnmp.entity.rfc3413.oneliner import cmdgen
from pysnmp.proto.rfc1902 import OctetString
from gettext import gettext as _

import argparse
import logging
import operator
import socket
import sys
import subprocess

logging.basicConfig(level=logging.INFO)
logger = logging.getLogger()

class ERRNO():
  OK = 0
  WARNING = 1
  CRITICAL = 2
  UNKNOWN = 3
  


def snmpwalk(host, oid):
  errorIndication, errorStatus, errorIndex, varBinds = cmdgen.CommandGenerator().bulkCmd(
    cmdgen.CommunityData('my-agent', 'public', 1),
    cmdgen.UdpTransportTarget((host, 161)),
    15, 0, # nonRepeaters, maxRepetitions
    oid
  )
  return varBinds

def main(host):
  try:
    lines = snmpwalk(host, '.1.3.6.1.4.1.2021.91.4.1.2')
    avm = int(str(lines[-2][0][1]).split()[3])/1024
    free = int(str(lines[-2][0][1]).split()[4])/1024

    if free > 100: 
      return ("MEM OK - %s MB | free=%s, avm=%s" % (free, free, avm), ERRNO.OK)
    elif free > 50:
      return ("MEM WARNING - %s MB | free=%s, avm=%s" % (free, free, avm), ERRNO.WARNING)
    else:
      return ("MEM CRITICAL - %s MB | free=%s, avm=%s" % (free, free, avm), ERRNO.CRITICAL)

  except socket.gaierror as e:
    return ("Failed: SNMP for host cannot be queried - %s" % e, ERRNO.CRITICAL)
  except Exception as e:
    return ("Failed: Script Exception - [%s] %s" % (type(e),e), ERRNO.CRITICAL)



if __name__ == '__main__':
  class NagiosArgumentParser(argparse.ArgumentParser):
    ''' Like exit code 128 on errors'''
    def error(self, message):
      self.print_usage(sys.stderr)
      self.exit(128, _('%s: error: %s\n') % (self.prog, message))

  parser = NagiosArgumentParser(
    description='Nagios Check InterLinks via SNMP.',
    formatter_class=argparse.ArgumentDefaultsHelpFormatter)

  parser.add_argument('-g', dest='debug', action='store_true', default=False, help="Set logging to debug")
  parser.add_argument('host', action='store', type=str, help="Hostname to use")
  args = parser.parse_args()

  if args.debug:
    logger.setLevel(logging.DEBUG)

  (msg, errno) = main(args.host)
  sys.stdout.write(msg + "\n")
  sys.exit(errno)