#!/bin/bash

#
# Copyright (c) 2002, 2003, 2004, 2005 Peter Palfrader <peter@palfrader.org>
#
# All rights reserved.
#

umask 037

set -e
set -u

DATE=`date "+%Y%m%d-%H%M%S"`
if [ -d /var/backups/local/mysql ]; then
	TARGET=/var/backups/local/mysql
elif [ -d /var/local/backup/mysql ]; then
	TARGET=/var/local/backup/mysql
elif [ -d /aux/dbbackup/mysql ]; then
	TARGET=/aux/dbbackup/mysql
else
	echo "Cannot find a backup target directory" >&2
	exit 1
fi

HOSTS="$@"
if [ -z "$HOSTS" ]; then
	HOSTS="localhost"
fi

if [ -z "${CONCURRENCY_LEVEL:-}" ]; then
	CONCURRENCY_LEVEL=1
fi

for host in $HOSTS; do
	if [ "$host" = "localhost" ]; then
		prefix="";
		postfix="";
	else
		shorthost=`echo "$host" | sed -e 's/\..*//'`
		prefix="$shorthost--";
		postfix="--$shorthost";
	fi
	mysqlcnf="$HOME/.my.cnf$postfix"
	if ! [ -e "$mysqlcnf" ]; then
		echo "Cannot find my.cnf for host $host: $mysqlcnf" >&2
		exit 1
	fi

	DBs=$(
	echo 'SHOW DATABASES;' | mysql --defaults-file="$mysqlcnf" --host="$host" | tail -n +2 |
	while read db; do
		if [ "$db" = "innodb" ] || [ "$db" = "test" ] || [ "$db" = "lost+found" ] ; then
			continue;
		fi
		echo $db;
	done
	);

	for db in $DBs; do
		file="$TARGET/$DATE-$prefix$db"
		mysqldump --defaults-file="$mysqlcnf" --host="$host" --opt --lock-tables -- "$db" > "$file"
	done

	for db in $DBs; do
		file="$TARGET/$DATE-$prefix$db"
		echo $file
	done | xargs --no-run-if-empty --max-procs "$CONCURRENCY_LEVEL" -n 1 bzip2

	for db in $DBs; do
		file="$TARGET/$DATE-$prefix$db"

		md5=`md5sum -- "$file.bz2" | awk '{print $1}'`
		if [ -e "$TARGET/MD5-$md5" ]; then
			rm -- "$file.bz2"
			ln "$TARGET/MD5-$md5" "$file.bz2"
		else
			ln "$file.bz2" "$TARGET/MD5-$md5"
		fi
	done
done