#!/bin/bash

##
## check_graphite_metric
##
## by kali (kali@kalimotxo.net) created for Sociomantic GmbH, 2014
##
##
## Checks for values provided by graphite interface.
## Accepts low and high ranges for warning and critical status.
##
## Depends on curl to retrieve the values from graphite interface.
##
## Specify the metric name with -m parameter, can use wildcards, but only ONE target per call.
## Retrieves current values collection with a "from" graphite parameter specifying time in the past,
##  which can be specified in parameters in the check. Useful for metrics with high intervals (e.g. 1 h)
## Ignores values received as "None" which means graphite has no points collected for the specified metric/timeframe
##
## Returns UNKNOWN status if can't retreive values from graphite.
##

# set this to your graphite settings. remove -u parameter for curl if you don't have http authentication
CURL_OPTIONS="-s -u YOUR_HTTP_USER:YOUR_HTTP_PASSWORD"
GRAPHITE_RENDER_URL="https://srv-monitor.sociomantic.com:8080/render/"

# Declare some defaults
EXIT_NAGIOS_STATUS=-1
CHECK_OUTPUT=""
# search string in metric to replace with the HOST parameter
METRIC_HOST_MATCHSTRING="%HOST%"
# default timeframe to check graphite for values
GRAPHITE_FROM_VALUE="5minutes"
# array to store metric names returned from graphite. used to keep graphite's response order
declare -a RES_METRICS
# assoc. array to store values for each metric. declared -A to iterate results and keep only the last not null value
declare -A RES_VALUES
# counter of passed threshold parameters
HAS_LO_PARAMS=0
HAS_HI_PARAMS=0

# define exit functions for nagios
exit_ok() {
echo "OK - ${CHECK_OUTPUT}"
exit 0
}
exit_war() {
echo "WARNING - ${CHECK_OUTPUT}"
exit 1
}
exit_cri() {
echo "CRITICAL - ${CHECK_OUTPUT}"
exit 2
}
exit_unk() {
echo "UNKNOWN - ${CHECK_OUTPUT}"
exit 3
}
# May this also be the inline documentation :)
show_usage() {
cat << EOF
Usage: $0 -w <warn_lvl_high> -c <crit_lvl_high> [-H host] -m <graphite_metric_substring>
-W [value]  : Value threshold to alert as warning when graphite goes above it (hi level)
-C [value]  : Value threshold to alert as critical when graphite goes above it (hi/hi level)
-w [value]  : (Optional) Lower warning value threshold (lo level) Ignored if absent.
-c [value]  : (Optional) Lower critical value threshold (lo/lo level) Ignored if absent.
-H [host]   : (Optional) Host string in the format dc-NNN. If present, it will be replaced in the graphite metric.
-f [time]   : (Optional) Graphite-formatted time frame to check the metric for, to append to "&from=-" on the url. Defaults to "${GRAPHITE_FROM_VALUE}".
-m [metric] : Graphite metric to be checked for values. If -H is present it will replace any occurence of the string "${METRIC_HOST_MATCHSTRING}" here.
Example:
$0 -W 20 -C 40 -m "eu-002.cacti_propulsor.cacti_propulsor_cpu-0*.cpu_usage"
WARNING - eu-002.cacti_propulsor.cacti_propulsor_cpu-02.cpu_usage=30.3966666667; eu-002.cacti_propulsor.cacti_propulsor_cpu-01.cpu_usage=22.8726666667; eu-002.cacti_propulsor.cacti_propulsor_cpu-03.cpu_usage=29.4873333333; eu-002.cacti_propulsor.cacti_propulsor_cpu-04.cpu_usage=27.258;

EOF
}

while getopts ":W:C:w:c:m:H:f:h" OPT ; do
	case "${OPT}" in
	W)
		WARN_LVL_HIGH=${OPTARG}
		(( ++HAS_HI_PARAMS ))
	;;
	C)
		CRIT_LVL_HIGH=${OPTARG}
		(( ++HAS_HI_PARAMS ))
	;;
	w)
		WARN_LVL_LOW=${OPTARG}
		(( ++HAS_LO_PARAMS ))
	;;
	c)
		CRIT_LVL_LOW=${OPTARG}
		(( ++HAS_LO_PARAMS ))
	;;
	m)
		METRIC_STRING=${OPTARG}
	;;
	H)
		HOST=${OPTARG}
	;;
	f)
		GRAPHITE_FROM_VALUE=${OPTARG}
	;;
	h)
		show_usage
		exit 0
	;;
	*)
		CHECK_OUTPUT="Can't parse parameters"
		exit_unk
	;;
	esac
done

# build base curl options for querying graphite. build the target metric passed as parameter over it
GRAPHITE_QUERY_BASE="${GRAPHITE_RENDER_URL}?format=raw&from=-${GRAPHITE_FROM_VALUE}&target="

# make sure we have all the necessary parameters
case $HAS_LO_PARAMS in
	1)
		CHECK_OUTPUT="Missing low level parameters. Passed -w=${WARN_LVL_LOW} -c=${CRIT_LVL_LOW}"
		exit_unk
	;;
	2)
		if `awk "BEGIN {exit !(${WARN_LVL_LOW} < ${CRIT_LVL_LOW})}"` ; then
			CHECK_OUTPUT="Low Warning threshold cannot be below critical threshold. Passed -w=${WARN_LVL_LOW} -c=${CRIT_LVL_LOW}"
			exit_unk
		fi
	;;
esac
case $HAS_HI_PARAMS in
	1)
		CHECK_OUTPUT="Missing high level parameters. Passed -W=${WARN_LVL_HIGH} -C=${CRIT_LVL_HIGH}"
		exit_unk
	;;
	2)
		if `awk "BEGIN {exit !(${WARN_LVL_HIGH} > ${CRIT_LVL_HIGH})}"` ; then
			CHECK_OUTPUT="High Warning threshold cannot be over critical threshold. Passed -W=${WARN_LVL_HIGH} -C=${CRIT_LVL_HIGH}"
			exit_unk
		fi
	;;
esac

## If HOST parameter is present, replace it in the metric variable
[ "$HOST" != "" ] && METRIC_STRING=$(sed "s/$METRIC_HOST_MATCHSTRING/$HOST/g" <<< $METRIC_STRING)

# Run query against graphite and store last non-none values on the array
for GRAPHITE_OUT in $(curl ${CURL_OPTIONS} ${GRAPHITE_QUERY_BASE}${METRIC_STRING} | sed 's/ //g') ; do
	GRAPHITE_METRIC=$(cut -f1 -d\| <<< $GRAPHITE_OUT | sed  's/,[0-9]*,[0-9]*,[0-9]*$//')
	RES_METRICS+=("$GRAPHITE_METRIC")
	for GRAPHITE_VALUE in $(cut -f2 -d\| <<< $GRAPHITE_OUT | sed 's/,/ /g') ; do
		[ "${GRAPHITE_VALUE,,}" != "none" ] && RES_VALUES[${GRAPHITE_METRIC}]=${GRAPHITE_VALUE}
	done
done

if [ ${#RES_VALUES[@]} -eq 0 ] ; then
	EXIT_NAGIOS_STATUS=3
	CHECK_OUTPUT="Graphite query ${METRIC_STRING} returned nothing."
else
	for METRIC in ${RES_METRICS[*]} ; do
		CHECK_OUTPUT="${CHECK_OUTPUT}${METRIC}=${RES_VALUES[$METRIC]}; "
		METRIC_STATUS=0
		if [ $HAS_LO_PARAMS -eq 2 ] ; then
			awk "BEGIN {exit !(${RES_VALUES["$METRIC"]} < $WARN_LVL_LOW)}" && METRIC_STATUS=1
			awk "BEGIN {exit !(${RES_VALUES["$METRIC"]} < $CRIT_LVL_LOW)}" && METRIC_STATUS=2
		fi
		if [ $HAS_HI_PARAMS -eq 2 ] ; then
			awk "BEGIN {exit !(${RES_VALUES["$METRIC"]} > $WARN_LVL_HIGH)}" && METRIC_STATUS=1
			awk "BEGIN {exit !(${RES_VALUES["$METRIC"]} > $CRIT_LVL_HIGH)}" && METRIC_STATUS=2
		fi
		[ $METRIC_STATUS -gt $EXIT_NAGIOS_STATUS ] && EXIT_NAGIOS_STATUS=$METRIC_STATUS
	done
fi

case $EXIT_NAGIOS_STATUS in
	0) exit_ok ;;
	1) exit_war ;;
	2) exit_cri ;;
	3) exit_unk ;;
	*) exit $EXIT_NAGIOS_STATUS ;;
esac