delorean.sh

#!/bin/bash
# Klaus Umbach <klaus-delorean@uxix.de>
# Licensed under the GPLv3

## Configuration

# default - may be overwritten in /etc/default/delorean
REMOTE_USER="delorean"
MAIL="user@domain.tld"
HOST="backupserver"
DEST_PATH="${HOSTNAME}"
LOCK_FILE="/var/run/delorean.pid"
LOG_FILE="/var/log/delorean.log"
REMOTE_LOCK_FILE="/tmp/delorean.lock.${HOSTNAME}"
REMOTE_LOG_FILE="delorean.log.${HOSTNAME}"
LAST_FILE="/var/lib/delorean.lastrun"
STATUS_FILE="/var/lib/delorean.status"
DISABLE_MOBILE="yes"

# only use real filesystems on real devices, no CDROM/DVDs
PATHS="$(mount | grep '^/dev' | egrep -v '(udf|iso9660|helper=udisks)' | awk '{print $3}' | tr '\n' ' ')"

# Just predefined for user-defined excludes.
EXCLUDE=""

## binaries

FLUXCAPACITOR="/usr/bin/ssh"
rsync="/usr/bin/nice -n 19 /usr/bin/rsync --delete -aHAXxv"
remote_rsync="/usr/bin/rsync"
ionice="/usr/bin/ionice -c3"
date="/bin/date"

# Read external configuration, if available
test -e /etc/default/delorean && source /etc/default/delorean

remote_message_command="/usr/bin/mail -E -s 'Delorean: Remote error on ${HOST}' ${MAIL}"

export RSYNC_RSH="${FLUXCAPACITOR}"

# TODO: CLI-parameters

# Year/Month/Day
today="$(${date} +%Y/%m/%d)"

function loginfo () { # {{{ Do the logging and update statusfile
	message="${1}"
	while read i; do
		echo "[STATUS: INFO] $(${date} +%Y-%M-%d\ %H:%M:%S) ${i}" >> ${LOG_FILE}
	done <<< "$message"

	if [ "x${2}" != "xNOSTATUS]" ] ; then
		echo "${message}" > ${STATUS_FILE}
	fi
} # }}}

## MAIN

# minimal check if the host is there
if ! host $HOST > /dev/null 2> /dev/null ; then
	loginfo "Backuphost $HOST not reachable, no backup now."
	exit 0 
fi

# get the currently used network device type
netDeviceType=$(/bin/ip route | \
		grep default | \
		head | \
		cut -d ' ' -f 5 | \
		sed -e 's/[0-9]*//g' \
	)

# if using a mobile network, stop here.
if [ "x${DISABLE_MOBILE}" == "xyes" ]; then
	if [ "x${netDeviceType}" == "xppp" ]; then
		loginfo "Currently mobile, no backup now."
		exit 0
	fi
fi

# These are the files/directories, I find useless to backup on a
# desktop/notebook computer.  I'm open to suggestions here!

SYS_EXCLUDE="var/cache/apt/ tmp/ var/run/ var/lib/apt/lists/ var/lib/clamav/ \
	var/lib/upower/ var/lib/sudo/ var/spool/exim4/ var/log/ var/mail/ \
	$LAST_FILE var/cache/openafs $LOCK_FILE mlocate.db var/cache/samba/ \
	.xsession-errors etc/resolv.conf .*.swp etc/mtab var/lib/dhcp/ dev/ \
	var/cache/man/ $STATUS_FILE var/cache/system-tools-backends .cache"

ALL_EXCLUDE="$SYS_EXCLUDE $EXCLUDE"

# build the exclude-options
for i in $ALL_EXCLUDE; do
	exclude="$exclude --exclude=$i" 
done

# If we can use another user than root, we need to take care of the attributes
# and permissions via xattrs, so the destination filesystem needs to be mounted
# with "-o user_xattrs"

if [ "x${REMOTE_USER}" != "xroot" ] ; then
	fake_super="--rsync-path=${remote_rsync} --fake-super"
else
	fake_super=''
fi


# Assemble the local sync-command
sync_command="${ionice} ${rsync} ${exclude} ${fake_super} ${PATHS} ${REMOTE_USER}@${HOST}:${DEST_PATH}/trunk"


# Assemble the remote command to set the hardlinks.
remote_command="( touch ${REMOTE_LOCK_FILE} && \
	cd ${DEST_PATH} && \
	mkdir -p ${today} && \
	${ionice} nice -19 cp -al trunk ${today}/$(${date} +%H-%M) && \
	rm ${REMOTE_LOCK_FILE} )2>&1 "


# local lockfile checking
if [ -e ${LOCK_FILE} ]; then
	if [ -d /proc/$(cat ${LOCK_FILE}) ]; then
		if grep ${0} /proc/$(cat ${LOCK_FILE}) ; then
			loginfo "still running"
			exit 0
		fi
	fi
# and remote lockfile checking
elif ${FLUXCAPACITOR} ${REMOTE_USER}@${HOST} "test -e ${REMOTE_LOCK_FILE}"; then 
			loginfo "Still running on the remote side."
			exit 0
else
	echo ${$} >  ${LOCK_FILE}

	# Now here happens the real backup.
	loginfo "Backup started"
	if (${sync_command} >> ${LOG_FILE}); then # TODO: sane logging

		# if the sync was successful, we drop the command to set the hardlinks
		${FLUXCAPACITOR} ${REMOTE_USER}@${HOST} "( ${remote_command} | ${remote_message_command} >/dev/null 2>&1 & disown )"

		# write it to syslog.
		loginfo "Backup successful"
		$date +%s > ${LAST_FILE}
		rm -f ${LOCK_FILE}
	else
		rm ${LOCK_FILE}
		loginfo "Something went wrong. Trying again next time."
	fi
fi