#!/bin/bash

# This script checks swap pageouts and reports number of kbytes moved 
# from physical ram to swap space in a given number of seconds
#
# Usage: "check_swap_activity -i interval  -w warning_kbyts  -c critical_kbytes
#
#

set -eu

. /usr/lib/nagios/plugins/utils.sh


help() {
cat << EOH
usage: $0 [ -i ## ] -w ## -c ## 

Measures page-outs to swap over a given interval, by default 5 seconds.

   -i time in seconds to monitor (defaults to 5 seconds)
   -w warning Level in kbytes
   -c critical Level in kbytes

EOH
}

TIMEWORD=seconds
WARN_LVL=
CRIT_LVL=
INTERVAL=5
## FETCH ARGUMENTS
while getopts "i:w:c:" OPTION; do
        case "${OPTION}" in
                i)
                        INTERVAL=${OPTARG}
                        if [ $INTERVAL -eq 1 ]; then
                            TIMEWORD=second
                        fi
                        ;;
                w)
                        WARN_LVL=${OPTARG}
                        ;;
                c)
                        CRIT_LVL=${OPTARG}
                        ;;
                ?)
                        help
                        exit 3
                        ;;
        esac
done

if [ -z ${WARN_LVL} ] || [ -z ${CRIT_LVL} ]  ; then
        help
        exit 3
fi

## Get swap pageouts over $INTERVAL
PAGEOUTS=$(vmstat -w ${INTERVAL} 2 | tail -n 1 | awk '{print $8}')

SUMMARY="| swapout_size=${PAGEOUTS}KB;${WARN_LVL};${CRIT_LVL};"
if [ ${PAGEOUTS} -lt ${WARN_LVL} ]; then
        # pageouts are below threshold
        echo "OK - ${PAGEOUTS} kb swapped out in last ${INTERVAL} ${TIMEWORD} $SUMMARY"
        exit $STATE_OK
elif [ ${PAGEOUTS} -ge ${CRIT_LVL} ]; then
        ## SWAP IS IN CRITICAL STATE
        echo "CRITICAL - ${PAGEOUTS} kb swapped out in last ${INTERVAL} ${TIMEWORD} $SUMMARY" 
        exit $STATE_CRITICAL
elif [ ${PAGEOUTS} -ge ${WARN_LVL} ] && [ ${PAGEOUTS} -lt ${CRIT_LVL} ]; then
        ## SWAP IS IN WARNING STATE
        echo "WARNING - ${PAGEOUTS} kb swapped out in last ${INTERVAL} ${TIMEWORD} $SUMMARY"
        exit $STATE_WARNING
else
        echo "CRITICAL: Failure to process pageout information $SUMMARY"
        exit $STATE_UNKNOWN
fi