#!/bin/sh
# -*- sh -*-

: << =cut

=head1 NAME

procbyuser - Plugin to monitor the amount of processes owned by a user

=head1 INSTALLATION

Place in /etc/munin/plugins/ (or link it there using ln -s)

=head1 CONFIGURATION

Add this to your /etc/munin/plugin-conf.d/munin-node:

 [procbyuser]
 user root               # required if /proc can't be read from by any user!
 env.USERS root yann     # defaults to ALL, i.e. display all users. 'root' is counted as one of the 'others'
 env.OTHER_FIELD others  # enable 'others'-list, set the label/field name

=head1 AUTHORS

Copyright (C) 2019 pcy <pcy@ulyssis.org>

Based on the plugin "cpubyuser".

=head1 MAGIC MARKERS

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

=cut

. "$MUNIN_LIBDIR/plugins/plugin.sh"

[ -z "$USERS" ] && USERS=ALL
if [ "$USERS" = "ALL" ]; then
	USERS="$(ps ax --format uname | tail +2 | sort -u | grep -v -e '^root$')"
fi

if [ "$1" = "autoconf" ]; then
	echo "yes"
fi

if [ "$1" = "config" ]; then
	echo "graph_args -r --lower-limit 0"
	echo "graph_title Processes per user"
	echo "graph_category processes"
	echo "graph_info This graph shows the amount of processes owned by a user."
	echo "graph_vlabel processes"
	echo "graph_scale no"
	echo "graph_period second"
	user_fields="$(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 processes of 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 -o user:42= -o cmd= | \
	awk -v USERS="$USERS" '
		!($2 ~ /^\[/) { NUSER[$1]=NUSER[$1]+1 } # filter away kernel threads
		END {
			others_sum = 0
			split(USERS, user_array)
			for (user in NUSER) {
				m = match(USERS,user)
				if (m != 0) {
					_user=user
					gsub(/[-.]/,"_",_user);
					print _user, (NUSER[user])
				} else
					others_sum += NUSER[user]
			}
			'"$OTHER_PRINT"'
		}' | while read -r user count; do
			# apply fieldname cleanup
			echo "$(clean_fieldname "$user").value $count"
		done