check_linux_uptime

#!/usr/bin/env python
# SnapServ/monitoring-plugins - Simple and reliable Nagios / Icinga plugins
# Copyright (C) 2016 - 2017 SnapServ Mathis
#
# 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/>.

import logging
import math
from datetime import timedelta

import nagiosplugin
from shared.common import NagiosPlugin

LOGGER = logging.getLogger('nagiosplugin')


class Uptime(nagiosplugin.Resource):
    def probe(self):
        LOGGER.info('Reading system uptime from /proc/uptime')
        with open('/proc/uptime') as file:
            raw_uptime = file.readline().split(' ')[0]
        LOGGER.debug('Raw system uptime is %s', raw_uptime)

        uptime_seconds = round(float(raw_uptime))
        yield nagiosplugin.Metric('uptime', uptime_seconds, min=0, uom='s', context='uptime')


class UptimeContext(nagiosplugin.Context):
    def __init__(self, warning=None, critical=None):
        super(UptimeContext, self).__init__('uptime', fmt_metric=self.fmt_uptime_metric)
        self.warning = nagiosplugin.Range(warning)
        self.critical = nagiosplugin.Range(critical)

    @staticmethod
    def fmt_uptime_metric(metric, _):
        return 'uptime is %s' % timedelta(seconds=metric.value)

    @staticmethod
    def fmt_range(rng):
        if rng.end == float('inf'):
            return 'less than %d minutes' % rng.start
        else:
            return 'outside range of %s to %s minutes' % (rng.start, rng.end)

    def evaluate(self, metric, resource):
        uptime_minutes = math.floor(metric.value / 60)
        if not self.critical.match(uptime_minutes):
            return self.result_cls(nagiosplugin.Critical, self.fmt_range(self.critical), metric)
        elif not self.warning.match(uptime_minutes):
            return self.result_cls(nagiosplugin.Warn, self.fmt_range(self.warning), metric)
        else:
            return self.result_cls(nagiosplugin.Ok, None, metric)


class UptimePlugin(NagiosPlugin):
    def declare_arguments(self):
        self.argument_parser.add_argument(
            '-w', '--warning', metavar='RANGE', default='',
            help='Return WARNING if response time is outside RANGE.'
        )
        self.argument_parser.add_argument(
            '-c', '--critical', metavar='RANGE', default='',
            help='Return CRITICAL if response time is outside RANGE.'
        )
        self.exclude_from_kwargs += ('warning', 'critical')

    def instantiate_check(self):
        return nagiosplugin.Check(
            Uptime(),

            UptimeContext(
                warning=self.arguments.get('warning'),
                critical=self.arguments.get('critical')
            )
        )


if __name__ == '__main__':
    UptimePlugin().execute()