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

: << =cut

=head1 NAME

dspam_ - Plugin to monitor various aspects of DSPAM performance

=head1 APPLICABLE SYSTEMS

Any system running a recent (3.8.0 or higher) DSPAM install.

=head1 CONFIGURATION

The plugin uses the output of the dspam_stats command, which is usually part
of any DSPAM install. You'll need to run this plugin as a user that has enough
rights to run dspam_stats and generate data for all users. This means that the
plugin needs to be run either as root, or as a user that has read access to
dspam.conf, and is added as a Trusted user in dspam.conf.

The following environment variables are used by this plugin:

 dspam_stats - Where to find the dspam_stats binary when it's not in
               $PATH (default: find anywhere in $PATH).
 statefile   - Where to read/write the statefile that is used to store
               dspam_stats output
               (default: $MUNIN_PLUGSTATE/dspam.state).
 warning     - When to trigger a warning (default: 95:).
 critical    - When to trigger a critical (default: 90:).
 pattern     - A pattern that is passed to grep in order to find the
               DSPAM uids to display. When this variable is set, the
               value of target (see USAGE) is ignored (default: empty).
 description - A string describing the set of uids selected by
               above pattern (default: empty).

Warning and critical values can also set on a DSPAM uid basis, use Munins
internal format for the DSPAM uid for this notation (see CONFIGURATION
EXAMPLES and USAGE for details).

=head2 CONFIGURATION EXAMPLES

 [dspam*]
 user root
 env.dspam_stats /opt/dspam/bin/dspam_stats
 env.statefile /tmp/dspam.state

 [dspam_accuracy*]
 env.critical 95:
 env.warning 96:

 # raise warning level for username@example.org
 env.username_example_org_warning 97:

 # show all accounts from one domain
 env.pattern @example\.org
 env.description domain example.org

=head1 USAGE

Link this plugin to /etc/munin/plugins/ and restart the munin-node. The link
should be in the format: dspam_<graph>_<target>, where:

 graph      - One of: accuracy, processed, processed_abs.
 target     - The uid that DSPAM generates in dspam_stats output,
              but converted to Munin internal name format. Normally
              this means that non-alphabetic and non-numeral characters
              are replaced by an underscore. For example,
              username@example.org will become username_example_org.
              A special case is uid ALL, which will draw a graph for
              a total of all uids, or for a list of all uids (depending
              on the graph type).
              NB For advanced uid selection such as 'all users of domain
              example.org', please see the environment variable 'pattern' 
              under CONFIGURATION.

=head1 INTERPRETATION

The plugin supports the following graph types:

 accuracy     - Shows the overall accuracy of all users as a
                percentage. The overall accuracy is the number of
                correctly classified messages (both ham and spam) in
                relation to the number of all processed messages.

 absprocessed - Shows the absolute numbers of mesages processed,
                sorted by the classification that DSPAM uses. The
                numbers are stacked, making the height of the column
                display the increase of processed messages over time.

 processed    - Shows the same data as dspam_processed_abs_, but as
                percentage of the total amount of processed messages,
                making it clear to see how the amounts of classified
                messages are divided.

=head1 AUTHOR

Copyright 2010 Tom Hendrikx <tom@whyscream.net>

=head1 LICENSE

GPLv2

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 dated June, 1991.

This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301 USA.

=head1 BUGS

None known. Please report to author when you think you found something.

=head2 TODO LIST

Currently developed and tested with bash/dash on linux.
More testing might be needed with other shells and OSes.

=head1 VERSION

$Id: dspam_ 72 2010-09-15 22:09:15Z tomhendr $

=head1 MAGIC MARKERS

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

=cut

# defaults for configurable settings
: ${dspam_stats:=$(which dspam_stats 2> /dev/null)}
: ${statefile:=${MUNIN_PLUGSTATE}/dspam.state}
: ${statefile_max_age:=180} # 3 minutes
: ${warning:=95:}
: ${critical:=90:}

# include munin plugin helper
. $MUNIN_LIBDIR/plugins/plugin.sh

#######################################
# Some generic file locking functions #
#######################################

#
# file_is_usable $file $max_age
#	Check if file is OK for usage: existing, readable and not too old
#
file_is_usable() {
	local file=$1
	local max_age=$2
	local lock=$file.lock

	[ ! -f $file ] && debug statefile $file does not exist && return 66 # EX_NOINPUT
	[ ! -r $file ] && debug statefile $file is not readable && return 65 # EX_DATAERR

	local mtime=$(stat --format %Y $file)
	local file_age=$(( $(date +%s) -mtime ))
	[ $file_age -gt $max_age ] && debug file $file is too old: $file_age seconds && return 65 # EX_DATAERR

	debug file $file is ok, $file_age seconds old
	return 0 # EX_OK
}

#
# file_get_lock $file
#	Obtain a lock for the named file
#
file_get_lock() {
	local file=$1
	local lock=$file.lock

	while file_is_locked $file; do
		sleep 1
	done

	echo $$ > $lock
	[ $? -gt 0 ] && debug failed to create lockfile $lock && return 73 # EX_CANTCREAT

	debug created lock for $file
	return 0 # EX_OK
}

#
# file_remove_lock $file
#	Remove a set lockfile for the named file
#
file_remove_lock() {
	local file=$1
	local lock=$file.lock

	rm -f $lock
	[ $? -gt 0 ] && debug failed to remove lockfile $lock && return 69 # EX_UNAVAILABLE

	debug removed lock for file $file
	return 0 # EX_OK
}

#
# file_is_locked $file
#	Check if a file is locked
#
file_is_locked() {
	local file=$1
	local lock=$1.lock

	[ -f $lock ] && debug file $file is locked && return 0 # EX_OK
	debug file $file is not locked
	return 69 # EX_UNAVAILABLE
}

####################################
# DSPAM output processing function #
####################################

#
# update_statefile
#	Read the output of dspam_stats, convert it and write usable data to the statefile
#
update_statefile() {

	file_is_usable $statefile $statefile_max_age && return $? # return when all OK
	! file_get_lock $statefile && return $? # return when locking failed

	local tmpfile=$(mktemp)
	debug created tmpfile $tmpfile

	debug starting $dspam_stats -t -S
	local t_start=$(date +%s)
	$dspam_stats -t -S | while IFS=' :' read a b c d e f g h i j k l m x; do
		# example of output format (3.9.1 rc1) for each user:
		#username@example.org
		#    TP:     0 TN:  2147 FP:     0 FN:    53 SC:     0 NC:     0
		#    SHR:    0.00%       HSR:    0.00%       OCA:   97.59%

		# or for short user names:
		#vmail    TP:80312082 TN:198342928 FP: 82941 FN: 57326 SC: 0 NC: 3498
		#         SHR:   99.56%       HSR:    0.00%       OCA:   99.69%

		case $a in
			TP)
				# the 2nd line
				local tp=$b tn=$d fp=$f fn=$h sc=$j nc=$l
				;;
			SHR)
				# the 3rd line
				local shr=$(echo $b | sed 's/%$//g')
				local hsr=$(echo $d | sed 's/%$//g')
				local oca=$(echo $f | sed 's/%$//g')

				# we're done, write data from current user to the statefile
				local clean_user=$(clean_fieldname $uid)
				local state="$uid $clean_user $tp $tn $fp $fn $sc $nc $shr $hsr $oca"
				echo $state >> $tmpfile
				[ $? -gt 0 ] && debug failed to write data for $uid to tmpfile && return 73 # EX_CANTCREAT
				debug wrote data for $uid to tmpfile: $state
				;;
			*)
				# the 1st line
				local uid=$a
				# data from 2nd line is also here
                                [ "$b" = "TP" ] && local tp=$c tn=$e fp=$g fn=$i sc=$k nc=$m
				;;
		esac
	done
	local t_end=$(date +%s)
	debug dspam_stats finished, runtime $((t_end - t_start)) seconds

	mv $tmpfile $statefile
	[ $? -gt 0 ] && debug failed to move tmpfile to $statefile && return 73 # EX_CANTCREAT
	debug moved tmpfile to $statefile

	file_remove_lock $statefile

	return 0 # EX_OK
}


#
# abs2perc
#	Outputs a percentage calculated from its two arguments
#
abs2perc() {
	# division by zero protection: debug output is merely informal and harmless ;)
	[ $1 -eq 0 ] && echo 0 && debug abs2perc prevented possible division-by-zero on first argument && return 0 # EX_OK
	[ $2 -eq 0 ] && echo 0 && debug abs2perc prevented possible division-by-zero on second argument && return 0 # EX_OK

	echo $1 $2 | awk '{ print $1 * 100 / $2 }'
}

#
# debug $output
#	Prints debugging output when munin-run is called with --pidebug argument (i.e. when MUNIN_DEBUG is set)
#
debug() {
	if [ -n "$MUNIN_DEBUG" ]; then
		echo "# DEBUG: $@"
	fi
}

########################################
# Functions that generate munin output #
########################################

#
# print_autoconf
#	Output for 'munin-node-configure' autoconf functionality
#
print_autoconf() {
	if [ -z "$dspam_stats" ]; then
		echo "no (no dspam_stats binary found)"
	elif [ ! -x $dspam_stats ]; then
		echo "no ($dspam_stats found but not executable)"
        else
                echo yes
        fi
}

#
# print_suggest
#	Output for 'munin-node-configure --suggest'
#
print_suggest() {
	echo accuracy_ALL
	echo processed_ALL
	echo absprocessed_ALL
}

#
# print_config
#	Output for 'munin-run <plugin> config' command.
#
print_config() {
	debug printing config for graph: $graph

	while file_is_locked $statefile; do
		debug statefile is locked, waiting
		sleep 1
	done

	case $graph in
		accuracy)
			if [ -n "$pattern" ]; then
				debug env.pattern was set, so use it: $pattern
				local uid=$description
				local uid_count=$(grep $pattern $statefile | wc -l)
				debug uid_count retrieved from statefile: $uid_count
			elif [ "$target" = "ALL" ]; then
				local pattern="-v TOTAL"
				debug target=ALL: need pattern for all users but not TOTAL: $pattern
				local uid="all users"
				local uid_count=$(grep $pattern $statefile | wc -l)
				debug uid_count retrieved from statefile: $uid_count
			else
				local pattern="\b$target\b"
				debug target=$target: need pattern for a single user: $pattern
				local uid=$(grep $pattern $statefile | cut -d' ' -f1)
				debug retrieved uid value from statefile: $uid
				local uid_count=1
			fi

			echo "graph_title Accuracy for $uid"
			echo graph_category spamfilter
			echo graph_args --base 1000 --upper-limit 100 --rigid
			echo graph_vlabel Accuracy in %
			echo "graph_info This graph shows the current DSPAM Overall Accuracy for $uid ($uid_count uids). Overall Accuracy is the percentage of messages that is classified correctly as either ham or spam."

			debug starting grep for user data in statefile
			local t_start=$(date +%s)
			grep $pattern $statefile | while read uid clean_user x; do
					echo $clean_user.label $uid
					print_warning $clean_user
					print_critical $clean_user
			done
			local t_end=$(date +%s)
			debug grep finished, runtime $((t_end - t_start)) seconds

			;;

		processed)
			if [ -n "$pattern" ]; then
				debug env.pattern was set, so use it: $pattern
				local uid=$description
				local uid_count=$(grep $pattern $statefile | wc -l)
				debug uid_count retrieved from statefile: $uid_count
			elif [ "$target" = "ALL" ]; then
				local pattern="-v TOTAL"
				debug target=ALL: need pattern for all users but not TOTAL: $pattern
				local uid="all users"
				local uid_count=$(grep $pattern $statefile | wc -l)
				debug uid_count retrieved from statefile: $uid_count
			else
				local pattern="\b$target\b"
				debug target=$target: need pattern for a single user: $pattern
				local uid=$(grep $pattern $statefile | cut -d' ' -f1)
				debug retrieved uid value from statefile: $uid
				local uid_count=1
			fi

			echo "graph_title Processed messages for $uid (%)"
			echo graph_category spamfilter
			echo graph_args --base 1000 --upper-limit 100 --rigid
			echo graph_vlabel Messages in %
			echo "graph_info This graph shows the messages that DSPAM processed for $uid ($uid_count uids) in percentages of all processed messages. Messages are divided in the following categories: true positives/negatives, false positives/negatives, and corpusfed ham/spam."
			echo tp.label True positives
			echo tp.info Spam messages correctly classified as spam.
			echo tp.draw AREASTACK
			echo tn.label True negatives
			echo tn.info Ham messages correctly classified as ham.
			echo tn.draw AREASTACK
			echo fp.label False positives
			echo fp.info Ham messages incorrectly classified as spam, but corrected by the user.
			echo fp.draw AREASTACK
			echo fn.label False negatives
			echo fn.info Spam messages incorrectly classified as ham, but corrected by the user.
			echo fn.draw AREASTACK
			echo sc.label Corpusfed spam
			echo sc.info Spam messages from a collected corpus for training purposes.
			echo sc.draw AREASTACK
			echo nc.label Corpusfed ham
			echo nc.info Ham messages from a collected corpus for training purposes.
			echo nc.draw AREASTACK
			;;

		absprocessed)
			if [ -n "$pattern" ]; then
				debug env.pattern was set, so use it: $pattern
				local uid=$description
				local uid_count=$(grep $pattern $statefile | wc -l)
				debug uid_count retrieved from statefile: $uid_count
			elif [ "$target" = "ALL" ]; then
				local pattern="-v TOTAL"
				debug target=ALL: need pattern for all users but not TOTAL: $pattern
				local uid="all users"
				local uid_count=$(grep $pattern $statefile | wc -l)
				debug uid_count retrieved from statefile: $uid_count
			else
				local pattern="\b$target\b"
				debug target=$target: need pattern for a single user: $pattern
				local uid=$(grep $pattern $statefile | cut -d' ' -f1)
				debug retrieved uid value from statefile: $uid
				local uid_count=1
			fi

			echo "graph_title Processed messages for $uid"
			echo graph_category spamfilter
			echo graph_args --base 1000
			echo graph_vlabel Messages
			echo graph_total Total
			echo "graph_info This graph shows the messages that DSPAM processed for $uid ($uid_count uids). Messages are divided in the following categories: true positives/negatives, false positives/negatives, and corpusfed ham/spam."
			echo tp.label True positives
			echo tp.info Spam messages correctly classified as spam.
			echo tp.draw AREASTACK
			echo tn.label True negatives
			echo tn.info Ham messages correctly classified as ham.
			echo tn.draw AREASTACK
			echo fp.label False positives
			echo fp.info Ham messages incorrectly classified as spam, but corrected by the user.
			echo fp.draw AREASTACK
			echo fn.label False negatives
			echo fn.info Spam messages incorrectly classified as ham, but corrected by the user.
			echo fn.draw AREASTACK
			echo sc.label Corpusfed spam
			echo sc.info Spam messages from a collected corpus for training purposes.
			echo sc.draw AREASTACK
			echo nc.label Corpusfed ham
			echo nc.info Ham messages from a collected corpus for training purposes.
			echo nc.draw AREASTACK
			;;

		*)
			debug no config available for graph: $graph, exiting with error
			exit 78 # EX_CONFIG
			;;
	esac
	debug finished with printing config for graph: $graph
}

#
# print_fetch
#	Output for 'munin-run <plugin> fetch' command: the actual data to graph.
#
print_fetch() {
	debug printing fetch for graph: $graph

	while file_is_locked $statefile; do
		debug statefile is locked, waiting
		sleep 1
	done

	case $graph in
		accuracy)
			if [ -n "$pattern" ]; then
				debug env.pattern was set, so use it: $pattern
				continue
			elif [ $target = "ALL" ]; then
				local pattern="-v TOTAL"
				debug target=ALL: need pattern for all users, but not for TOTAL: $pattern
			else
				local pattern="\b$target\b"
				debug target=$target: need pattern for a single user: $pattern
			fi

			debug starting grep for user data in statefile
			local t_start=$(date +%s)
			grep $pattern $statefile | while read x clean_user x x x x x x x x oca x; do
				echo $clean_user.value $oca
			done
			local t_end=$(date +%s)
			debug grep finished, runtime $((t_end - t_start)) seconds
			;;

		processed)
			if [ -n "$pattern" ]; then
				debug env.pattern was set, so use it: $pattern
				continue
			elif [ $target = "ALL" ]; then
				local pattern="TOTAL"
				debug target=ALL: need pattern for TOTAL of all users: $pattern
			else
				local pattern="\b$target\b"
				debug target=$target: need pattern for a single user: $pattern
			fi

			local tmpfile=$(mktemp) || debug failed to create tmpfile && debug tmpfile created at: $tmpfile
			debug starting grep for user data in statefile, sending to tmpfile
			local t_start=$(date +%s)
			grep $pattern $statefile > $tmpfile
			local t_end=$(date +%s)
			debug grep finished, runtime $((t_end - t_start)) seconds

			debug starting loop over data in tmpfile
			while read user x tp tn fp fn sc nc x; do
				debug read data for user $user: $tp $tn $fp $fn $sc $nc
				all_tp=$((all_tp + tp))
				all_tn=$((all_tn + tn))
				all_fp=$((all_fp + fp))
				all_fn=$((all_fn + fn))
				all_sc=$((all_sc + sc))
				all_nc=$((all_nc + nc))
				debug calculated new totals: $all_tp $all_tn $all_fp $all_fn $all_sc $all_nc
			done < $tmpfile
			debug finished data loop
			rm -f $tmpfile || debug failed to remove tmpfile && debug removed tmpfile

			local total=$((all_tp + all_tn + all_fp + all_fn + all_sc + all_nc))
			debug calculated total of all messages: $total
			echo tp.value $(abs2perc $all_tp $total)
			echo tn.value $(abs2perc $all_tn $total)
			echo fp.value $(abs2perc $all_fp $total)
			echo fn.value $(abs2perc $all_fn $total)
			echo sc.value $(abs2perc $all_sc $total)
			echo nc.value $(abs2perc $all_nc $total)
			;;

		absprocessed)
			if [ -n "$pattern" ]; then
				debug env.pattern was set, so use it: $pattern
				continue
			elif [ $target = "ALL" ]; then
				local pattern="TOTAL"
				debug target=ALL: need pattern for TOTAL of all users: $pattern
			else
				local pattern="\b$target\b"
				debug target=$target: need pattern for a single user: $pattern
			fi

			local tmpfile=$(mktemp) || debug failed to create tmpfile && debug tmpfile created at: $tmpfile
			debug starting grep for user data in statefile, sending to tmpfile
			local t_start=$(date +%s)
			grep $pattern $statefile > $tmpfile
			local t_end=$(date +%s)
			debug grep finished, runtime $((t_end - t_start)) seconds

			debug starting loop over data in tmpfile
			while read user x tp tn fp fn sc nc x; do
				debug read data for user $user: $tp $tn $fp $fn $sc $nc
				all_tp=$((all_tp + tp))
				all_tn=$((all_tn + tn))
				all_fp=$((all_fp + fp))
				all_fn=$((all_fn + fn))
				all_sc=$((all_sc + sc))
				all_nc=$((all_nc + nc))
				debug calculated new totals: $all_tp $all_tn $all_fp $all_fn $all_sc $all_nc
			done < $tmpfile
			debug finished data loop
			rm -f $tmpfile || debug failed to remove tmpfile && debug removed tmpfile

			echo tp.value $all_tp
			echo tn.value $all_tn
			echo fp.value $all_fp
			echo fn.value $all_fn
			echo sc.value $all_sc
			echo nc.value $all_nc
			;;

		*)
			debug no fetch available for graph: $graph, exiting with error
			exit 78 # EX_CONFIG
			;;
	esac
	debug finished printing fetch for graph: $graph
}


#####################
# Main process loop #
#####################

# show env settings
debug dspam_ plugin started, pid=$$
debug settings:
debug - dspam_stats is set to: $dspam_stats
debug - statefile is set to: $statefile
debug - statefile_max_age is set to: $statefile_max_age
debug - warning is set to: $warning
debug - critical is set to: $critical
debug - pattern is set to: $pattern
debug - description is set to: $description

command=$1
[ -n "$command" ] || command="fetch"
debug - command is set to: $command

graph=$(basename $0 | cut -d'_' -f2)
debug - graph is set to: $graph

target=$(basename $0 | cut -d'_' -f3-)
[ -n "$target" ] || target="ALL"
debug - target is set to: $target

debug settings completed, starting process

case $command in
	autoconf)
		print_autoconf
		;;
	suggest)
		print_suggest
		;;
	config)
		update_statefile
		print_config
		;;
	fetch)
		update_statefile
		print_fetch
		;;
esac

debug exiting
exit 0 # EX_OK