#!/bin/bash
#
# Plugin to monitor CPU usage, for a selected set of users
#
# Usage: Place in /etc/munin/node.d/ (or link it there using ln -s)
#	Add this to your /etc/munin/plugin-conf.d/munin-node:
#		[cpubyuser]
#		env.USERS root yann
#
#	If env.USERS is set to ALL, count all logged in users.
#
#	 root and yann being a list of the users to monitor.
#	 You need to also make sure that awk is installed
#
# 2008-12-08 v 1.3.1 Hanisch Elián:
#				- support for dots in user names.
#				- fix labels
#
# 2008-12-01 v 1.3 Hanisch Elián:
#				- fixes, refactoring and code cleanup
#				- Users that use cpu but aren't in the USERS env var
#				are plotted as "others", set others.graph to 'no' if
#				you	don't want this.
#
# 2008-03-20 v 1.2 fireball:	fixed minor screwup, works now ^^
#
# 2008-01-09 v 1.1 fireball:	fixed "-" in usernames, those get replaced by "_" now.
#				set usernames in config accordingly (that is with _)
#
#
# Parameters understood:
#
#	config		(required)
#	autoconf	(optional - used by munin-config)
#

#%# family=auto
#%# capabilities=autoconf

. "$MUNIN_LIBDIR/plugins/plugin.sh"

OTHER_FIELD="others"
[ "$USERS" = "ALL" ] && USERS=$(w --no-header | awk '{ print $1 }' | sort | uniq)


if [ "$1" = "autoconf" ]; then
	if [ -n "$USERS" ]; then
		echo "yes"
	else
		echo "no (USERS setting is missing)"
	fi
	exit
fi

if [ "$1" = "config" ]; then
	echo "graph_args --base 1000 -r --lower-limit 0"
	echo "graph_title CPU usage, by user"
	echo "graph_category system"
	echo "graph_info This graph shows CPU usage, for monitored users."
	echo "graph_vlabel %"
	echo "graph_scale no"
	echo "graph_period second"
	user_fields="$(for user in $USERS; do clean_fieldname "$user" | tr '\n' ' '; done)"
	echo "graph_order $user_fields $OTHER_FIELD"
	for user in $USERS "$OTHER_FIELD"; do
		user_field="$(clean_fieldname "$user")"
		echo "${user_field}.label $user"
		echo "${user_field}.info CPU used by user $user"
		echo "${user_field}.type GAUGE"
		echo "${user_field}.draw AREASTACK"
	done
	exit
fi

top -b -n 1 | sed '1,/^ *PID /d' | \
	awk -v USERS="$USERS" '
		# Store the CPU usage of each process - the mapping to the
		# user happens later. We cannot use the second column
		# (username) directly, since it may be abbreviated (ending
		# with "+").
		{ CPU_PER_PID[$1]=$9 }
		END {
			split(USERS, user_array)
			for (user_index in user_array) {
				user = user_array[user_index]
				# retrieve all process IDs belonging to the user
				"ps -u "user" -o pid --no-headers 2>/dev/null | tr \"\n\" \" \"" | getline pids
				user_cpu = 0
				split(pids, pid_array)
				# summarize the cpu usage of this usage
				for (pid_index in pid_array) {
					pid = pid_array[pid_index]
					user_cpu += CPU_PER_PID[pid]
					delete CPU_PER_PID[pid]
				}
				print user, user_cpu
			}
			# add all remaining cpu usages into "others"
			others_sum = 0
			for (other_usage in CPU_PER_PID) others_sum+=CPU_PER_PID[other_usage]
			print "'"$OTHER_FIELD"'", others_sum;
		}' | while read -r user count; do
			# apply fieldname cleanup
			echo "$(clean_fieldname "$user").value $count"
		done