munin plugin for proxy_cache by shell

#!/bin/bash

. $MUNIN_LIBDIR/plugins/plugin.sh

if [ "$1" = "autoconf" ]; then
        echo yes
        exit 0
fi

if [ "$1" = "config" ]; then
    echo 'graph_title Nginx cache hit rat's
    #    echo 'graph_args --base 1000 -l 0'
    echo 'graph_category nginx'
    echo 'graph_vlabel Numbers'
    echo 'hit.label hit'
    echo 'miss.label miss'
    echo 'graph_info numbers of HIT and MISS every five minutes'
    exit
fi

log="/var/log/nginx/access.log"
allnumber=$(wc -l $log |awk '{print $1}')

#get time for 5 minute ago
ftime=$(date -d '5 minute ago' +"%Y:%H:%M" |head -n 1)

#get line number at specify time
startline=$(grep -no "$ftime" $log |head -n 1 |awk -F ":" '{print $1}')
liveline=$(($allnumber - $startline))
allline=$(tail -n $liveline $log)

#get result
echo "miss.value $(echo -e "$allline" |awk '{if ($NF=="cs=MISS") print "m"}' |wc -l |grep -o '[0-9].*')"
echo "hit.value $(echo -e "$allline" |awk '{if ($NF=="cs=HIT") print "h"}' |wc -l |grep -o '[0-9].*')"