munin plugin for monitoring nginx request times

# Setup an appropriate nginx log_format in the `http` section of your nginx config:

    log_format  main  '$remote_addr $time_iso8601 "$request" '
                      '$status $body_bytes_sent "$http_referer" '
                      '"$http_host" '
                      '"$http_user_agent" "$http_x_forwarded_for" '
                      '$request_time ';
                      
# Then save the following as a munin plugin to monitor the last 5 minutes of your nginx access.log file

#!/bin/bash
#%# family=manual

LOGFILE=/var/log/nginx/access.log
[[ -e $LOGFILE ]] || exit 0

case $1 in
    config)
        echo graph_title Nginx requests time
        echo graph_category nginx
        echo "avg_request_time.label Average request time (s)"
        echo avg_request_time.warning 1
        echo avg_request_time.critical 3
        exit 0
        ;;
esac

avg=$(cat $LOGFILE | grep -av '/longpolling' | tail -n 60000 | awk -v threshold=`date -Isec -d '5 min ago'` 'threshold < $2 { sum += $NF; n++ } END { if(n > 0) print sum/n }')

echo -n "avg_request_time.value "
echo ${avg:-0}

exit 0