#!/bin/bash

# varnish.sh
# Rackspace Cloud Monitoring Plugin to collect metrics from varnishstat.
#
# Copyright (c) 2013, Rob Szumski <rob@robszumski.com>
# 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.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "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 COPYRIGHT HOLDER OR CONTRIBUTORS 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.
#
# See https://github.com/robszumski/rackspace-monitoring-varnish for a readme
# and more information
#
# this plugin can optinally print particular statistics, just pass them as args
# varnish.sh cache_hit,cache_hitpass,cache_miss
#
#
# Example Criteria
# if (metric['healthy_backends'] < 1) {
#    return new AlarmStatus(CRITICAL, 'Varnish doesnt have any backends!');
#}
#
#if (metric['healthy_backends'] < 2) {
#    return new AlarmStatus(WARNING, 'Varnish only has #{healthy_backends} healthy backend.');
#}
#
# NOTE: if you are running Varnish < 4 comment out healthy backends metrics (they don't work)
#

return new AlarmStatus(OK, 'Varnish has \#{healthy_backends} backends.');

# check if service is running
SERVICE=varnish
VARNISHSTAT=/usr/bin/varnishstat
VARNISHADM=/usr/bin/varnishadm

if P=$(pgrep $SERVICE | wc -l)
then
    echo "status $SERVICE is running ($P instances)"
else
    echo "status $SERVICE is not running"
fi

# output number of processes
echo "metric processes int32 $P"

# calculate hit percent
hits=$($VARNISHSTAT -1 -f cache_hit | awk '{print $2}')
connections=$($VARNISHSTAT -1 -f client_req| awk '{print $2}')
hit_percent=$(echo "scale=8;($hits/$connections)" | bc | awk '{printf "%f", $1*100}')
echo "metric hit_percent double "$hit_percent

# calculate # of healthy backends
healthy=$($VARNISHADM backend.list | grep -c "Healthy")
echo "metric healthy_backends int32" $healthy

[ ! -z $1 ] && $VARNISHSTAT -1 -f $1 | awk ' { print "metric " $1 " gauge " $2 } '