#!/usr/bin/env python
# Copyright (c) 2018 Pure Storage, Inc.
#
## Overview
#
# This short Nagios/Icinga plugin code shows  how to build a simple plugin to monitor Pure Storage FlashArrays.
# The Pure Storage Python REST Client is used to query the FlashArray occupancy indicators.
# Plugin leverages the remarkably helpful nagiosplugin library by Christian Kauhaus.
#
## Installation
#
# The script should be copied to the Nagios plugins directory on the machine hosting the Nagios server or the NRPE
# for example the /usr/lib/nagios/plugins folder.
# Change the execution rights of the program to allow the execution to 'all' (usually chmod 0755).
#
## Dependencies
#
#  nagiosplugin      helper Python class library for Nagios plugins by Christian Kauhaus (http://pythonhosted.org/nagiosplugin)
#  purestorage       Pure Storage Python REST Client (https://github.com/purestorage/rest-client)

__author__ = "Eugenio Grosso"
__copyright__ = "Copyright 2018, Pure Storage Inc."
__credits__ = "Christian Kauhaus"
__license__ = "Apache v2.0"
__version__ = "1.2"
__maintainer__ = "Eugenio Grosso"
__email__ = "geneg@purestorage.com"
__status__ = "Production"

"""Pure Storage FlashArray occupancy status

   Nagios plugin to retrieve the overall occupancy from a Pure Storage FlashArray or from a single volume.
   Storage occupancy indicators are collected from the target FA using the REST call.
   The plugin has two mandatory arguments:  'endpoint', which specifies the target FA and 'apitoken', which
   specifies the autentication token for the REST call session. A third optional parameter, 'volname' can
   be used to check a specific named value. The optional values for the warning and critical thresholds have
   different meausure units: they must be expressed as percentages in the case of checkig the whole FlashArray
   occupancy, while they must be integer byte units if checking a single volume.

"""

import argparse
import logging
import nagiosplugin
import purestorage
import urllib3


_log = logging.getLogger('nagiosplugin')

class PureFAoccpy(nagiosplugin.Resource):
    """Pure Storage FlashArray  occupancy

    Calculates the overall FA storage occupancy or a single volume capacity.

    """

    def __init__(self, endpoint, apitoken, volname):
        self.endpoint = endpoint
        self.apitoken = apitoken
        self.volname = volname

    @property
    def name(self):
        if (self.volname is None):
            return 'PURE_FA_OCCUPANCY'
        else:
            return 'PURE_FA_VOL_OCCUPANCY'


    def get_perf(self):
        """Gets performance counters from flasharray."""
        urllib3.disable_warnings(urllib3.exceptions.InsecureRequestWarning)
        fa = purestorage.FlashArray(self.endpoint, api_token=self.apitoken)
        if (self.volname is None):
            fainfo = fa.get(space=True)[0]
        else:
            fainfo = fa.get_volume(self.volname, space=True)

        fa.invalidate_cookie()
        return(fainfo)

    def probe(self):

        fainfo = self.get_perf()
        _log.debug('FA REST call returned "%s" ', fainfo)
        if (self.volname is None):
            occupancy = round(float(fainfo.get('total'))/float(fainfo.get('capacity')), 2) * 100
            metric = nagiosplugin.Metric('FA occupancy', occupancy, '%', min=0, max=100, context='occupancy')
        else:
            occupancy = int(fainfo.get('volumes'))
            metric = nagiosplugin.Metric(self.volname + ' occupancy', occupancy, 'B', min=0, context='occupancy')
        return metric


def parse_args():
    argp = argparse.ArgumentParser()
    argp.add_argument('endpoint', help="FA hostname or ip address")
    argp.add_argument('apitoken', help="FA api_token")
    argp.add_argument('--vol', help="FA volume name. If omitted the whole FA occupancy is cecked")
    argp.add_argument('-w', '--warning', metavar='RANGE', default='',
                      help='return warning if occupancy is outside RANGE. Value has to be expressed in percentage for the FA, while in bytes for the single volume')
    argp.add_argument('-c', '--critical', metavar='RANGE', default='',
                      help='return critical if occupancy is outside RANGE. Value has to be expressed in percentage for the FA, while in bytes for the single volume')
    argp.add_argument('-v', '--verbose', action='count', default=0,
                      help='increase output verbosity (use up to 3 times)')
    argp.add_argument('-t', '--timeout', default=30,
                      help='abort execution after TIMEOUT seconds')
    return argp.parse_args()


@nagiosplugin.guarded
def main():
    args = parse_args()
    check = nagiosplugin.Check( PureFAoccpy(args.endpoint, args.apitoken, args.vol) )
    check.add(nagiosplugin.ScalarContext('occupancy', args.warning, args.critical))
    check.main(args.verbose, args.timeout)

if __name__ == '__main__':
    main()