#!/usr/bin/env python

# check_xiv_hardusage: A Nagios plugin which lets you monitor
#                      remaining space on an IBM XIV storage
#                      system.

# Rationale:
# You may use SNMP to query an XIV storage system for various 
# usage status numbers, but the SNMP measurement points don't
# reveal the most crucial of values: Whether at least one pool
# is approaching its hard limit; detecting this is very important
# if you work with thin-provisioned pools.

# This Nagios plugin uses the XIV command line interface to
# query pool usage and capacity. The command line utility is
# not as light-weight as one might like, so this Nagios plugin
# may take a while to respond.

# Note that the xcli tool creates a ~nagios/.xiv directory;
# inside this, there is a GUI10/logs directory (among others).
# A new, small file is added to the logs-directory every time
# the xcli utility is run, and hence also every time a Nagios
# check is run. It seems there is no way to turn this off.
# You may want to set up a cleaning-task which keeps the
# number of files low, e.g. using tmpwatch.

# A Nagios configuration may refer to this plugin via a command
# and service definition like this:
# define command {
#    command_name    check_xiv_hardusage
#    command_line    /usr/local/nagios/check_xiv_hardusage -H $HOSTADDRESS$ -u username -p LKujw3f -w 80 -c 90
# }
#
#define service {
#        service_description             Pool hard usage
#        host_name                       xiv1
#        check_command                   check_xiv_hardusage
#        use                             generic-service
#        contacts                        xiv_operations
#        normal_check_interval           30
# }

# Author: Troels Arvin <tra@sst.dk>
# Versioning:
# $Revision: 15269 $
# $Date: 2011-02-08 13:27:02 +0100 (Tue, 08 Feb 2011) $

# Updated versions of this Nagios plugin will be made available at
# http://troels.arvin.dk/code/nagios/check_xiv_hardusage

# Copyright (c) 2011, Danish National Board of Health.
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:
#     * Redistributions of source code must retain the above copyright
#       notice, this list of conditions and the following disclaimer.
#     * Redistributions in binary form must reproduce the above copyright
#       notice, this list of conditions and the following disclaimer in the
#       documentation and/or other materials provided with the distribution.
#     * Neither the name of the  the Danish National Board of Health nor the
#       names of its contributors may be used to endorse or promote products
#       derived from this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY the Danish National Board of Health ''AS IS'' AND ANY
# EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
# WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
# DISCLAIMED. IN NO EVENT SHALL the Danish National Board of Health BE LIABLE FOR ANY
# DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
# (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
# LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
# ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
# SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

# (Most of the script is wrapped in a big try-block, so that 
# errors in the script are treated in a way which is interpreted
# as an UNKNOWN state in Nagios.)
try:
    import os
    import sys
    import subprocess
    import getopt
    import csv

    this_script = os.path.basename(__file__)

    # Defaults
    hostname           = 'xiv'
    username           = 'nagios'
    password           = 'nagios'
    thres_w            = 85
    thres_c            = 95
    consider_all_pools = False
    do_debug           = False

    # Helper functions
    def debug(msg):
        if do_debug:
            print "debug: %s" % msg

    def usage():
        print (
            """Usage:
  %s [ -H <hostname> ] [ -u <username> ] [ -p <password> ] 
        [ -w <warning threshold pct> ] [ -c <critical threshold pct> ]
        [ -a ] [ -d ]

hostname may be a hostname or an IP address.

-a: consider all storage pools for alarming, even those 
    without thin provisioning

-d: turn on debugging

Defaults:
    hostname              : %s
    username              : %s
    password:             : %s
    warning  threshold pct: %d
    critical threshold pct: %d

Communicates with the XIV storage system, and for each storage pool the
current used-value is compared with the hard size. If used/hard rised
above indicated percentages, a non-OK status is returned.
By default, only pools with thin provisioning are considered for
alarms.

Example usage:
  %s -H xiv1 -u someuser -p passw0rd -w 80 -c 90

The XIV user being used should be a Read Only account on the XIV system.
The XIV client utilities take a long time to start up, and aren't exactly
light-weight. Thus, such Nagios checks should be run too often.""" %
            (
                this_script,
                hostname,
                username,
                password,
                thres_w,
                thres_c,
                this_script
            )
        )
        sys.exit(3)

    # Args handling and sanity checks
    try:
        options, args = getopt.getopt(sys.argv[1:], "H:adu:p:w:c:h", ['help'])
    except getopt.GetoptError:
        usage()

    for name, value in options:
        if name=='-H':
            hostname = value
        elif name=='-d':
            do_debug = True
        elif name=='-a':
            consider_all_pools = True
        elif name=='-u':
            username = value
        elif name=='-p':
            password = value
        elif name=='-c':
            try:
                thres_c = int(value)
            except Exception:
                print "Unable to convert CRITICAL threshold to integer\n"
                usage()
        elif name=='-w':
            try:
                thres_w = int(value)
            except Exception:
                print "Unable to convert WARNING threshold to integer\n"
                usage()
        else:
            usage()

    if thres_w >= thres_c:
        print "WARNING-threshold (%d) greater than CRITICAL-threshold (%d)" % (
            thres_w,
            thres_c
        )
        sys.exit(3)

    if thres_w < 0 or thres_w > 100 or thres_c < 0 or thres_c > 100:
        print 'Thresholds need to be between 0 and 100'
        sys.exit(3)

    debug("Thresholds: warn=%d; crit=%d" % (thres_w, thres_c))

    # The XIV command line utilities don't live in a common place,
    # so we look for the xcli utility in the path, and other
    # places.
    xcli_path = None
    special_dirs = ['/usr/local/XIVGUI','/opt/XIVGUI','/opt/ibm/XIVGUI']

    # Add the special directories to the general path, and go searching
    # for the xcli command line utility
    dlist = os.environ['PATH'].split(':') + special_dirs
    for d in dlist:
        fullpath = os.path.join(d,'xcli')
        if os.path.exists(fullpath):
            xcli_path = fullpath
            break

    if xcli_path is None:
        print('xcli not found')
        sys.exit(3)


    # Ready to work

    # Call out to xcli
    cmd = [
        'xcli',
        '-u', username,
        '-p', password,
        '-m', hostname,
        '-t', 'name,soft_size,hard_size,used_by_volumes',   # which columns to pull
        '-s',                                               # CSV output, please
        'pool_list'                                         # xcli command
    ]
    p = subprocess.Popen(cmd, executable=xcli_path, stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
    output = p.communicate()[0]
    debug("Output: %s" % output)
    retval = p.returncode
    if retval <> 0:
        print "xcli command failed with return code %d and message '%s'" % (
            retval,
            output.replace('\n',' ')
        )
        sys.exit(3)

    lines = output.split('\n')

    # The xcli utility may emit annoying (but benign) Java warnings that we want
    # to skip, and we don't want the header-line.
    cut_point = None
    i = 0
    for line in lines:
        if (line.find('"Name","Size (GB)","Hard Size (GB)"') >= 0):
            cut_point = i+1
            break
        i += 1
    if cut_point is None:
        print "Could not find header line in output from xcli"
        sys.exit(3)
    lines = lines[cut_point:]

    # Build structures from the CSV returned by xcli
    pools = []
    softs = []
    hards = []
    useds = []
    pcts  = []
    try:
        reader = csv.reader(lines)
        for r in reader:

            # output may contain empty lines
            if len(r) == 4:
                pools.append(r[0])
                softs.append(float(r[1]))
                hards.append(float(r[2]))
                useds.append(float(r[3]))
    except:
        print "Could not parse output from xcli"
        sys.exit(3)

    # Calculate percentages
    i = 0
    highest_pct = 0
    crits = []
    warns = []
    for pool in pools:
        used = useds[i]
        soft = softs[i]
        hard = hards[i]
        pct = int(round((used / hard) * 100))
        # Conditinal evaluation, based on whether to consider
        # hard-provisioned pools, or not
        if consider_all_pools or (soft < hard):
            if pct > highest_pct:
                highest_pct = pct
            if (pct >= thres_w and pct < thres_c):
                warns.append(pool)
            if (pct >= thres_c):
                crits.append(pool)
        pcts.append(pct)
        debug(
            "pool=%s; soft=%d, hard=%d, used=%d; pct=%d" % (
                pool,
                soft,
                hard,
                used,
                pct
            )
        )
        i += 1

    # Prepare Nagios exit code and status string
    nagios_ret = 0
    nagios_str = 'XIV capacity OK: No pool hard usage above thresholds'
    if (highest_pct >= thres_w and highest_pct < thres_c):
        nagios_ret = 1
        nagios_str = 'XIV capacity WARNING: At least one pool (%s) has hard usage pct >= %d' % (
            ','.join(warns),
            thres_w
        )
    if (highest_pct >= thres_c):
        nagios_ret = 2
        nagios_str = 'XIV capacity CRITICAL: At least one pool (%s) has hard usage pct >= %d' % (
            ','.join(crits),
            thres_c
        )

    # Prepare performance data string
    perf_str_elems = []
    i = 0
    # Performance data labels should be unique within the first
    # 19 characters, so choose naming in order to try to
    # fulfill this.
    for pool in pools:
        perf_str_elems.append(
            "'%s rel hard usage'=%d%%;%d;%d" % (
                pool,
                pcts[i],
                thres_w,
                thres_c
            )
        )
        perf_str_elems.append(
            "'%s abs hard usage'=%dGB" % (
                pool,
                hards[i]
            )
        )
        i += 1

    # Final output
    print "%s| %s" % (
        nagios_str,
        ' '.join(perf_str_elems)
    )
    sys.exit(nagios_ret)

# ==========================================================
# Error and exit handling
# ==========================================================
except SystemExit, e:
    # Special case which is needed in order to convert the return code
    # from other exception handlers.
    sys.exit(int(str(e)))
except:
    # At this point, we don't know what's going on, so let's
    # not output the details of the error into something which
    # would appear in the Nagios web interface.
    print "UNKNOWN - An unhandled error occurred. "
    sys.stderr.write('Unhandled error: %s' % sys.exc_info()[1])
    sys.exit(3)