#!/bin/sh

# Munin plugin for monitoring Postfix per-instance mail throughput.
# 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"

case "${1:-}" in
    config) cat <<- EOF
		graph_title Postfix per-instance bytes throughput
		graph_vlabel bytes per \${graph_period}
		graph_args --base 1024 -l 0
		graph_scale yes
		graph_period minute
		graph_category postfix
	EOF
    if [ $(echo "${postmulti:-postfix}" | wc -w) -gt 1 ]; then
        echo graph_total total throughput
    fi
    for postfix in ${postmulti:-postfix}; do
        echo "${postfix}_volume.label" "$postfix throughput"
        echo "${postfix}_volume.type"  DERIVE
        echo "${postfix}_volume.min"   0
    done
    exit 0
    ;;
esac

if [ ! -f "$LOGFILE" ]; then
    for postfix in ${postmulti:-postfix}; do
        echo "${postfix}_volume.value U"
    done
    exit 0;
fi

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

logtail -f"$LOGFILE" -o"$STATEFILE" >"$tmpfile"

for postfix in ${postmulti:-postfix}; do
    echo -n "${postfix}_volume.value "
    sed -nr "s#^\w{3} [ :[:digit:]]{11} [._[:alnum:]-]+ $postfix/qmgr\[[[:digit:]]+\]: [[:xdigit:]]+: from=<[^>]*>, size=([[:digit:]]+), nrcpt=[[:digit:]]+ \(queue active\)\$#\1#p" "$tmpfile" \
    | awk 'BEGIN{x=0} {x+=$0} END{print x}'
done