#!/usr/bin/python
##########################################################################
# Copyright (C) 2018  Igor Castro
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>
###########################################################################
###########################################################################
# Version = 1.0
# Organisation = IATA 
# Author = I.CASTRO
# Description = 
# Nagios check in python to fetch by snmpwalk Cisco 
# OID related to license expiration and trigger alarm based on it.
# OID is 1.3.6.1.4.1.9.9.543.1.2.3.1.16 which is clmgmtLicenseEndDate
# 
# snmp Output Format is like "Hex-STRING: 07 E1 0C 12 17 00 00 00"
#  07 E1 = 2017
#  0C = 12
#  12 = 18
#
##########################################################################
import os, sys, time, argparse
from datetime import date

# Hardcoded parameters to debug
my_command="snmpwalk"
target_OID="1.3.6.1.4.1.9.9.543.1.2.3.1.16"
#warning_arg=int("60")
#critical_arg=int("30")

# exit statuses recognized by Nagios
OK = 0
WARNING = 1
CRITICAL = 2
UNKNOWN = 3

# Create a Parser to get value from command arguments

parser = argparse.ArgumentParser(description='Nagios check to collect by snmp Cisco license expiration date and evaluate the status')

parser.add_argument('-c', default=30, dest='critical', type=int, help='critical threshold for nagios (default: 30)')
parser.add_argument('-w', default=90, dest='warning', type=int, help='warning threshold for nagios (default: 90)')
parser.add_argument('-H', dest='host', help='target host')
parser.add_argument('--snmp', dest='snmp', help='snmp argument in form  \"-v 3 -a MD5 -A authpass -l authPriv -u username -x des -X password -r 5 -t 30\"')

args = parser.parse_args()

#test = parser.parse_args(['var_critical'])
warning_arg=args.warning
critical_arg=args.critical
my_host=args.host
snmp_parameters=args.snmp

# Create the actual snmpwalk command with all parameters
#snmp_command="%s -a %s -A %s -l %s -u %s -x %s -X %s %s %s" % (my_command,snmp3_auth_hash,snmp3_auth_pass,snmp3_mode,snmp3_user,snmp3_enc_cypher,snmp3_enc_pass,my_host,target_OID)

snmp_command="%s %s %s %s" % (my_command,snmp_parameters,my_host,target_OID)

# Print snmpwalk command 
#print "snmp_command is %s" % snmp_command
result_snmp=os.popen(snmp_command).readline().strip()

# Detect when Hex data is starting just after Hex-STRING: value
date_str=result_snmp.find("Hex-STRING:")+12

# If snmpwalk failed for any reason date_str=-1 +12
if date_str == 11 :
	print "UNKNOWN"
        sys.exit(UNKNOWN)
else :

	# SNMPWALK Result has a valid hex value
	
	# Detect end of string to display only valuable data (eg License expiration date)
	end_str=len(result_snmp)
	#print "OK - command output %s " % result_snmp[date_str:end_str]

	# Split Hex value separated by space
	date_hex=result_snmp[date_str:end_str].split(" ")

	# Detect Year of expiration and convert it back to decimal value
	date_year="%s%s" % (date_hex[0],date_hex[1])
	date_year_int= int (date_year, 16)
	date_year=str(date_year_int)

	# Detect Month of expiration and convert it back to decimal value
	date_month="%s" % (date_hex[2])
	date_month_int= int (date_month, 16)
	date_month=str(date_month_int)

	# Detect Day of expiration and convert it back to decimal value
	date_day="%s" % (date_hex[3])
	date_day_int= int (date_day, 16)
	date_day=str(date_day_int)

	# Calculate current today value in days
	today = date.today()
	expiration_date=date(date_year_int,date_month_int,date_day_int)
	remaining_day = expiration_date - today
	
	# Check if the remaining number of days is less than crtitical threshold 
	if remaining_day.days < critical_arg :
		print "CRITICAL - license will expire on %s/%s/%s as dd/mm/yyyy which is less than critical threshold %d" % (date_day,date_month,date_year,critical_arg)
		sys.exit(CRITICAL)
		
	# Check if the remaining number of days is less than warning threshold 	
	if remaining_day.days < warning_arg :
		print "WARNING - license will expire on %s/%s/%s as dd/mm/yyyy which is less than warning threshold %d" % (date_day,date_month,date_year,warning_arg)
		sys.exit(WARNING)
	else :
		print "OK - license will expire on %s/%s/%s as dd/mm/yyyy which is more than warning threshold %d" % (date_day,date_month,date_year,warning_arg)
		sys.exit(OK)