#!/bin/sh

# Copyright (c) 2002, 2003, 2004, 2005, 2017 Peter Palfrader <peter@palfrader.org>
#
# Permission is hereby granted, free of charge, to any person obtaining
# a copy of this software and associated documentation files (the
# "Software"), to deal in the Software without restriction, including
# without limitation the rights to use, copy, modify, merge, publish,
# distribute, sublicense, and/or sell copies of the Software, and to
# permit persons to whom the Software is furnished to do so, subject to
# the following conditions:
#
# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

umask 037

set -e
set -u

DATE=`date "+%Y%m%d-%H%M%S"`

#PORT="-p 5433"
if [ -z "${PORT:-}" ]; then
	PORT=""
else
	PORT="-p $PORT"
fi
if [ -z "${PREFIX:-}" ]; then
	PREFIX=""
else
	PREFIX="$PREFIX-"
fi

if [ -d /var/backups/local/pg ]; then
	BASE=/var/backups/local/pg
elif [ -d /var/local/backup/pg ]; then
	BASE=/var/local/backup/pg
elif [ -d /aux/dbbackup/pg ]; then
	BASE=/aux/dbbackup/pg
elif [ -d /srv/dbbackup/pg ]; then
	BASE=/srv/dbbackup/pg
else
	echo "Cannot find a backup target directory" >&2
	exit 1
fi

if [ -z "${PGHOST:-}" ] &&
   [ -z "${PGUSER:-}" ]; then
	SUDO="sudo -u postgres"
elif [ -n "${PGHOST:-}" ] &&
     [ -n "${PGUSER:-}" ]; then
	SUDO=""
else
	echo "Need to either set both or none of PGHOST, PGUSER" >&2
	exit 1
fi

$SUDO psql $PORT --quiet --no-align --tuples-only --command "SELECT datname FROM pg_database" |
while read db; do
	if [ "$db" = "template0" -o "$db" = "template1" ] ; then
		continue;
	fi

	file="$BASE/$DATE-$PREFIX$db.plain"
	$SUDO pg_dump $PORT --create --format=p "$db" > "$file"
	nice pigz --no-name --no-time -- "$file"

	digest=`sha256sum -- "$file.gz" | awk '{print $1}'`
	if [ -e "$BASE/DGST-$digest" ]; then
		rm -- "$file.gz"
		ln "$BASE/DGST-$digest" "$file.gz"
	else
		ln "$file.gz" "$BASE/DGST-$digest"
	fi
done