#! /usr/bin/env python
# $Id: check_disk.py 8 2009-03-15 17:41:58Z  $

"""

NAME

	check_disk.py -- report whenever target disk space is below threshold.
    
SYNOPSIS

	check_disk.py -p <path> -w <warning threshold> -c <critical threshold> [ -h ] [ --log ]

	Options:
	  --version             show program's version number and exit
	  -h, --help            show this help message and exit
	  -p TARGET_PATH, --path=TARGET_PATH
             	           Path to device to monitor
	  -c CRIT_THRESHOLD, --critical=CRIT_THRESHOLD
	                        Critical free space threshold in percentage
	  -w WARN_THRESHOLD, --warning=WARN_THRESHOLD
	                        Warning free space threshold in percentage
	  --log                 Set logging on

RETURN CODES

	0 when monitored target is OK
	1 when monitored target is over WARNING threshold
	2 when monitored target is over CRITICAL threshold

EXAMPLE

	$ ./check_disk.py -p / -c 80 -w 90 --log
	WARNING: / free space: 612930211840
	$ echo $?
	1	

AUTHOR
		
	Petri Koistinen <petri.koistinen@iki.fi>

	Adapted from scripts and ideas stolen all around the Internet.
			
"""

version = '$Revision: 8 $'

from optparse import OptionParser
import sys, os
import logging
import logging.handlers
import statvfs # Only available in UNIX.

logger = logging.getLogger('check_disk')
logger.setLevel(logging.DEBUG)
handler = logging.handlers.SysLogHandler('/dev/log')
logger.addHandler(handler)

# Parse commandline options:
parser = OptionParser(usage="%prog -p <path> -w <warning threshold> -c <critical threshold> [ -h ] [ --log ]", version="%prog " + version)
parser.add_option("-p", "--path", action="store", type="string", dest="target_path", help="Path to device to monitor")
parser.add_option("-c", "--critical", action="store", type="string", dest="crit_threshold", help="Critical free space threshold in percentage")
parser.add_option("-w", "--warning", action="store", type="string", dest="warn_threshold", help="Warning free space threshold in percentage")
parser.add_option("", "--log", action="store_true", dest="log", default=False, help="Set logging on")
(options, args) = parser.parse_args()

def free_space(path):
    """ freespace(path) -> integer
    Return the number of free bytes available to the user on the file system
    pointed to by path."""
    s = os.statvfs(path)
    return s[statvfs.F_BAVAIL] * s[statvfs.F_BSIZE]

def total_space(path):
    """ totalspace(path) -> integer
    Return the number of total bytes on the file system
    pointed to by path."""
    s = os.statvfs(path)
    return s[statvfs.F_BLOCKS] * s[statvfs.F_FRSIZE]	

def log(message):
    """ log(message)
    Print message to screen.
    Write message also to syslog if --log command line option is specified."""
    print message
    if options.log:
        logger.error(os.path.basename(sys.argv[0]) + ': ' + message)
  
def check_space():
    if not options.target_path:
        log("UNKNOWN: Missing monitoring target path.")
        sys.exit(1)
    if not options.crit_threshold:
        log("UNKNOWN: Missing critical threshold value.")
        sys.exit(1)
    if not options.warn_threshold:
        log("UNKNOWN: Missing warning threshold value.")
        sys.exit(1)
    if int(options.crit_threshold) >= int(options.warn_threshold):
        log("UNKNOWN: Critical percentage can't be equal to or bigger than warning percentage.")
        sys.exit(1)

    percent_free = float(free_space(options.target_path)) / float(total_space(options.target_path)) * 100 

    if percent_free < float(options.crit_threshold):
        log("CRITICAL: " + options.target_path + " free space: " + str(free_space(options.target_path)))
        sys.exit(2)
    if percent_free < float(options.warn_threshold):
        log("WARNING: " + options.target_path + " free space: " + str(free_space(options.target_path)))
        sys.exit(1)

    sys.exit(0)

if __name__ == '__main__':
    check_space()