#!/bin/sh
#
# Plugin to monitor CPU usage, for a selected set of users
#
# Usage: Place in /etc/munin/plugins/ (or link it there using ln -s)
#	Add this to your /etc/munin/plugin-conf.d/munin-node:
#		[cpubyuser]
#		user root # required if /proc can't be read from by any user!
#		env.USERS root yann
#		env.OTHER_FIELD others # enable 'others'-list, set the label/field name
#
#	root and yann being a list of the users to monitor.
#
#	If env.USERS is set to ALL, count all logged in users, and if set to
#	ALLPROC, *all* users with a running process will be listed, except for root.
#
#	You need to also make sure that awk is installed
#
# 2019-08-30 v 1.4 pcy <pcy@ulyssis.org>:
#				- add USERS=ALLPROC, not relying on a tty or pty being present for user detection
#				- OTHERS_FIELD now defaults to disabled, explicitly give it a
#				  value to re-enable it (eg. 'others')
#				- use ps(1) instead of top(1) for easier and more robust
#				  parsing/summary calculation
#
# 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"

[ -z "$USERS" ] && USERS=ALL
if [ "$USERS" = "ALLPROC" ]; then
	USERS="$(ps ax --format uname | tail +2 | sort -u | grep -v -e '^root$')"
elif [ "$USERS" = "ALL" ]; then
	USERS="$(w --no-header | cut -d' ' -f 1 | sort -u)"
fi

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

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

OTHER_PRINT=""
[ -z "$OTHER_FIELD" ] || OTHER_PRINT="print \"$(clean_fieldname "$OTHER_FIELD")\", others_sum;"

ps ax --format "%cpu user" | tail +2 | \
	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_USER[$2]=$1 }
		END {
			others_sum = 0
			split(USERS, user_array)
			for (user in CPU_USER) {
				m = match(USERS,user)
				if (m != 0) {
					_user=user
					gsub(/[-.]/,"_",_user);
					print _user, (CPU_USER[user])
				} else
					others_sum += CPU_USER[user]
			}
			'"$OTHER_PRINT"'
		}' | while read -r user count; do
			# apply fieldname cleanup
			echo "$(clean_fieldname "$user").value $count"
		done