#!/bin/bash

#USAGE: check_pressure cpu|io|memory some|full [--10 w,c] [--60 w,c] [--300 w,c]

RESULTS=(OK WARNING CRITICAL UNKNOWN)

fail() {
	local RET=$1
	shift
	echo "$@"
	exit $RET
}

float_compare() {
	[ $# -ne 2 ] && return 1

	(( $(echo "$1 > $2" | bc -l ) )) && return 0
	return 1
}

# pressure is a relatively new feature. Ignore if not present.
[ ! -e "/proc/pressure" ] && fail 0 pressure API not present

RESOURCE="$1"
[ ! -e "/proc/pressure/$RESOURCE" ] && fail 3 invalid resource \""$RESOURCE"\"
shift

( echo "$1" | grep "^some$\|^full$" > /dev/null ) \
	|| fail 3 \""$1"\" invalid. must be \"some\" or \"full\"
MODE="$1"

while shift; do
	case "$1" in
		"--10")
			VAL[0]="$2"
			shift;;
		"--60")
			VAL[1]="$2"
			shift;;
		"--300")
			VAL[2]="$2"
			shift;;
		"");;
		*)
			fail 3 "Unkown argument: \"$1\""
			;;
	esac
done

[ "${#VAL[@]}" -eq 0 ] && fail 3 "At least one set of threshholds must be set"

read MD avg10 avg60 avg300 catch < <(grep "$MODE" "/proc/pressure/$RESOURCE") \
	|| fail 3 "Parsing of file failed. Does $RESOURCE support $MODE?"

AVG=( "$avg10" "$avg60" "$avg300" )
WARNING_OFFENDERS=()
CRITICAL_OFFENDERS=()

for i in 0 1 2; do
	[ -z "${VAL[$i]}" ] && continue
	IFS=',' read WARN CRIT <<< "${VAL[$i]}"
	IFS='=' read KEY VALUE <<< "${AVG[$i]}"

	float_compare "$VALUE" "$CRIT" && CRITICAL_OFFENDERS+=("$KEY($VALUE)=C") && continue
	float_compare "$VALUE" "$WARN" && WARNING_OFFENDERS+=("$KEY($VALUE)=W")
done

WORST=0
[ ${#WARNING_OFFENDERS[@]} -gt 0 ] && WORST=1
[ ${#CRITICAL_OFFENDERS[@]} -gt 0 ] && WORST=2

echo "PRESSURE ${RESULTS[$WORST]}: ${CRITICAL_OFFENDERS[@]} ${WARNING_OFFENDERS[@]} | ${AVG[@]}"