#!/bin/sh

# Munin plugin for monitoring Postfix per-service and per-instance
# usage.  Symlink/rename to 'postfix_sasl_$SERVICE_$SYSLOGNAME'.
# Copyright © 2015 Guilhem Moulin <guilhem@fripost.org>
#
# 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, either version 3 of the License, or
# (at your option) any later version.
#
# 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, see <http://www.gnu.org/licenses/>.

PATH=/usr/bin:/bin:/usr/sbin:/sbin
set -u

LOGFILE="/var/log/${logfile:-mail.log}"
STATEFILE="$MUNIN_PLUGSTATE/${0##*/}.offset"

name="${0##*/}"
name="${name#postfix_stats_}"

if [ "${name#postscreen_}" != "$name" ]; then
    postfix="${name#postscreen_}"
    service=postscreen
    fields='connected accepted passed'
elif [ "${name#smtpd_}" != "$name" ]; then
    postfix="${name#smtpd_}"
    service=smtpd
    fields='connected accepted queued'
elif [ "${name#qmgr_}" != "$name" ]; then
    postfix="${name#qmgr_}"
    service=qmgr
    fields='queued'
elif [ "${name#smtp_}" != "$name" ]; then
    postfix="${name#smtp_}"
    service=smtp
    fields='sent deliverable deferred undeliverable bounced'
elif [ "${name#lmtp_}" != "$name" ]; then
    postfix="${name#lmtp_}"
    service=lmtp
    fields='sent deliverable deferred undeliverable bounced'
elif [ "${name#pipe_}" != "$name" ]; then
    postfix="${name#pipe_}"
    service=pipe
    fields='sent deliverable deferred undeliverable bounced'
fi

case "${1:-}" in
    config) cat <<- EOF
		graph_title Postfix $service message throughput ($([ -n "$postfix" -a "$postfix" != postfix ] && echo "'${postfix#postfix-}'" || echo default) instance)
		graph_vlabel mails per \${graph_period}
		graph_args --base 1000 -l 0
		graph_scale no
		graph_period minute
		graph_category postfix
	EOF
    for field in $fields; do
        echo "$field.label $field"
        echo "$field.type DERIVE"
        echo "$field.draw AREA"
        echo "$field.min 0"
    done
    exit 0
    ;;
esac

if [ ! -f "$LOGFILE" ]; then
    for field in $fields; do
        echo "$field.value U"
    done
    exit 0;
fi

tmpfile="$(mktemp --tmpdir)"
trap 'rm -f "$tmpfile"' EXIT

logtail -f"$LOGFILE" -o"$STATEFILE" | sed -nr "s#^\w{3} [ :[:digit:]]{11} [._[:alnum:]-]+ $postfix/$service\[[[:digit:]]+\]: ##p" >"$tmpfile"

case "$service" in
    postscreen)
        connected=$(grep -Ec "^CONNECT from\s"                 "$tmpfile")
        rejected=$( grep -Ec "^NOQUEUE: reject:\s"             "$tmpfile")
        passed=$(   grep -Ec "^(PASS (OLD|NEW)|WHITELISTED)\s" "$tmpfile")
        echo connected.value $connected
        echo accepted.value $(($rejected + $passed))
        echo passed.value   $passed
    ;;
    smtpd)
        connected=$(grep -Ec "^connect from\s"         "$tmpfile")
        rejected=$( grep -Ec "^NOQUEUE: reject:\s"     "$tmpfile")
        queued=$(   grep -Ec "^[[:xdigit:]]+: client=" "$tmpfile")
        echo connected.value $connected
        echo accepted.value  $(($rejected + $queued))
        echo queued.value    $queued
    ;;
    qmgr)
        queued=$(grep -Ec "^[[:xdigit:]]+: from=<\S+>, .*\(queue active\)$" "$tmpfile")
        echo queued.value $queued
    ;;
    smtp|lmtp|pipe)
        for field in $fields; do
            v=$(grep -Ec "^[[:xdigit:]]+:( [^ =]+=\S+,)+ status=$field(\s.*)?$" "$tmpfile")
            echo $field.value $v
        done
    ;;
esac