#!/bin/bash

# munin_xml_generator - an integration of Monitis/M3 with Munin
# Written by Dan Fruehauf <malkodan@gmail.com>

# this will usually not change
declare -r MUNIN_DIR=/var/lib/munin

# TODO some end in g.rrd, c.rrd and d.rrd - find out the meaning of it
declare -r MUNIN_RRD_SUFFIX=".rrd"

# this is the tag prefix in monitis
declare -r MONITIS_TAG_PREFIX="munin"

# prints XML header
print_header() {
	echo '<?xml version="1.0"?>'
	echo '<config>'
	echo '	<apicredentials apikey="%API_KEY%" secretkey="%SECRET_KEY%"/>'
	echo '	<agent name="Munin Agent" interval="60">'

}

# print XML footer
print_footer() {
	echo '	</agent>'
	echo '</config>'
}

# prints a M3 XML for a munin host
# $1 - hostname
# $2 - monitor (optional)
print_xml() {
	local hostname=$1; shift
	local monitor=$1; shift
	print_header
	if [ x"$monitor" != x ]; then
		print_xml_for_monitor $hostname $monitor
	else
		for monitor in `list_monitors $hostname`; do
			print_xml_for_monitor $hostname $monitor
		done
	fi
	print_footer
}

# print a XML for a single monitor and all its counters
# $1 - hostname
# $2 - monitor
print_xml_for_monitor() {
	local hostname=$1; shift
	local monitor=$1; shift
	# monitor header
	echo "		<monitor name=\"$monitor\" tag=\"${MONITIS_TAG_PREFIX}_${hostname}\">"
	# this line will extract the timestamp
	echo "			<exectemplate>rrdtool lastupdate $MUNIN_DIR/$hostname/$hostname-$monitor-*-*$MUNIN_RRD_SUFFIX | tail -1 | cut -d: -f1</exectemplate>"
	local monitor_uom=`get_monitor_uom $hostname $monitor`

	local counter
	for counter in `list_counters_for_monitor $hostname $monitor`; do
		echo "			<exectemplate>rrdtool lastupdate $MUNIN_DIR/$hostname/$hostname-$monitor-$counter-*$MUNIN_RRD_SUFFIX | tail -1 | cut -d: -f2</exectemplate>"
	done

	# this will extract the time of the test
	echo '			<metric name="MONITIS_CHECK_TIME">'
	echo '				<type>integer</type>'
	echo '				<uom>timestamp</uom>'
	echo '				<line>1</line>'
	echo '			</metric>'

	local -i i=2
	for counter in `list_counters_for_monitor $hostname $monitor`; do
		echo "			<metric name=\"$counter\">"
		echo "				<type>integer</type>"
		echo "				<uom>$monitor_uom</uom>"
		echo "				<line>$i</line>"
		echo "			</metric>"
		let i=$i+1
	done
	echo "		</monitor>"
}

# list all hosts
list_hosts() {
	(cd $MUNIN_DIR && ls -1d */ | cut -d'/' -f1 | grep -v "^plugin-state$") | sort | uniq
}

# list all monitors
# $1 - munin directory
# $2 - hostname
list_monitors() {
	local hostname=$1; shift
	ls -1 $MUNIN_DIR/$hostname/$hostname-* | cut -d'-' -f2 | sort | uniq
}

# returns the counters a monitor supports
# $1 - hostname
# $2 - monitor name
list_counters_for_monitor() {
	local hostname=$1; shift
	local monitor=$1; shift
	(cd $MUNIN_DIR/$hostname && ls -1 $hostname-$monitor-* | cut -d'-' -f3) 2> /dev/null
}

# returns the UOM (unit of measurement) of a monitor
# $1 - hostname
# $2 - monitor name
get_monitor_uom() {
	local hostname=$1; shift
	local monitor=$1; shift
	grep "$hostname;$hostname:$monitor\.graph_vlabel" $MUNIN_DIR/datafile | cut -d' ' -f2-
}

# $1 - hostname
# $2 - monitor
main() {
	local hostname=$1; shift
	local monitor=$1; shift
	if [ x"$hostname" != x ]; then
		print_xml $hostname $monitor
	else
		echo "Usage: $0 hostname [ monitor ]"
		return 1
	fi
}

main "$@"