#!/bin/bash
#
# Copyright (C) 2007 Francois Marier <francois@debian.org>
#
# This backup script 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 2 of the
# License, or (at your option) any later version.
#
# This script 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 Email-Reminder; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
# 02110-1301, USA.
#
# Usage:
#   backup 					automatic backup
#   backup --full				force a full backup
#   backup --list-current-files			list of files currently backed up
#   backup --file-to-restore directory/foo	restore the given file as "./restored_foo"
#
# Note that the following files should be in the same directory as this script:
# 
#   include		Files and directories to include in the backup (one per line)
#   exclude		From the directories previously mentioned, which ones to omit
#   id_rsa		Private ssh key for the backup host
#   id_rsa.pub		Public ssh key for the backup host (copied there as .ssh/authorized_keys)
#   known_hosts		Contains the fingerprints for the backup host

# -----------START OF USER CONFIGURATION------------

# HINT: Generate a good passphrase using "pwgen -s 16"
GPG_PASSWORD="" 

# The directory where this script and all the configuration files are located
BACKUP_HOME="/home/my_username/.backup"

# The name of the database to backup
WIKIDB="wikidb"

# The MySQL root password
MYSQL_PASSWORD="mysql_root_password"

# To limit the SCP transfers to a certain number of bytes per second
SCP_LIMIT="520"

# How many days to keep the old backups
OLDAGE="9D"

# Which host (using ssh) to copy the backup to
SSH_HOST="username@some_host.somewhere.net"

# -----------END OF USER CONFIGURATION------------

# Internal variables
SSH_IDENTITY="IdentityFile=$BACKUP_HOME/id_rsa"
SSH_HOSTKEY="UserKnownHostsFile=$BACKUP_HOME/known_hosts"
SSH="ssh -o $SSH_IDENTITY -o $SSH_HOSTKEY"
SCP="scp -q -l $SCP_LIMIT -o $SSH_IDENTITY -o $SSH_HOSTKEY"
SFTP="sftp -o $SSH_IDENTITY -o $SSH_HOSTKEY"
INCLUDE_FILE="$BACKUP_HOME/include"
EXCLUDE_FILE="$BACKUP_HOME/exclude"
DUMP_FILE="$BACKUP_HOME/$WIKIDB-dump.sql"
PKG_FILE="$BACKUP_HOME/dpkg-selections"

# Create the backup directory in case it doesn't exist
$SSH $SSH_HOST mkdir -p $HOSTNAME

# If the list of files has been requested, only do that
if [ "$1" = "--list-current-files" ]; then
	SCP="scp -q -o $SSH_IDENTITY -o $SSH_HOSTKEY"
	PASSPHRASE=$GPG_PASSWORD duplicity --list-current-files --ssh-command "$SSH" --scp-command "$SCP" --sftp-command "$SFTP" scp://$SSH_HOST/$HOSTNAME
	exit 0

# Restore the given file
elif [ "$1" = "--file-to-restore" ]; then
	if [ "$2" = "" ]; then
		echo "You must specify a file to restore"
		exit 2
	fi
	SCP="scp -q -o $SSH_IDENTITY -o $SSH_HOSTKEY"
	PASSPHRASE=$GPG_PASSWORD duplicity --ssh-command "$SSH" --scp-command "$SCP" --sftp-command "$SFTP" --file-to-restore "$2" scp://$SSH_HOST/$HOSTNAME restored_`basename $2`
	exit 0

# Catch invalid arguments
elif [ "$1" != "--full" -a "$1" != "" ]; then
	echo "Invalid argument: $1"
	exit 1
fi

# Delete files related to failed backups
PASSPHRASE=$GPG_PASSWORD duplicity cleanup --verbosity 1 --sftp-command "$SFTP" scp://$SSH_HOST/$HOSTNAME

# Delete old expired backups
PASSPHRASE=$GPG_PASSWORD duplicity --force --remove-older-than $OLDAGE --verbosity 1 --sftp-command "$SFTP" scp://$SSH_HOST/$HOSTNAME

# Dump Wiki DB and list of Debian packages
mysqldump --opt $WIKIDB -uroot -p$MYSQL_PASSWORD > $DUMP_FILE
dpkg --get-selections > $PKG_FILE

# Check whether a full backup was requested
FULLBACKUP=""
if [ "$1" = "--full" ]; then
	FULLBACKUP="--full"
fi

# Do the actual backup using Duplicity
PASSPHRASE=$GPG_PASSWORD duplicity $FULLBACKUP --no-print-statistics --remove-older-than $OLDAGE --verbosity 1 --exclude-device-files --include $PKG_FILE --include $DUMP_FILE --exclude-globbing-filelist $EXCLUDE_FILE --include-globbing-filelist $INCLUDE_FILE --exclude '**' --ssh-command "$SSH" --scp-command "$SCP" --sftp-command "$SFTP" / scp://$SSH_HOST/$HOSTNAME

# Cleanup the temporary files
rm -f $DUMP_FILE
rm -f $PKG_FILE