backupninja/handlers/maildir.in

# -*- mode: sh; sh-basic-offset: 3; indent-tabs-mode: nil; -*-

###############################################################
#
#  This handler slowly creates a backup of each user's maildir
#  to a remote server. It is designed to be run with low overhead
#  in terms of cpu and bandwidth so it runs pretty slow.
#  Hardlinking is used to save storage space.
#
#  each users maildir will contain these files:
#    daily.1
#    daily.2
#    daily.3
#    weekly.1
#    weekly.2
#    monthly.1
#  if keepdaily is 3, keepweekly is 2, and keepmonthly is 1. 
#  the actual maildir is stored within each snapshot directory.
#
#  The basic algorithm is to rsync each maildir individually,
#  and to use hard links for retaining historical data.
#
#  We handle each maildir individually because it becomes very
#  unweldy to hardlink and rsync many hundreds of thousands
#  of files at once. It is much faster to take on smaller
#  chunks at a time. 
#
#  For the backup rotation to work, destuser must be able to run 
#  arbitrary bash commands on the desthost.
#
#  Any maildir which is deleted from the source will be moved to
#  "deleted" directory in the destination. It is up to you to 
#  periodically remove this directory or old maildirs in it.
# 
##############################################################

getconf rotate yes
getconf remove yes
getconf backup yes

getconf loadlimit 5
getconf speedlimit 0
getconf keepdaily 5
getconf keepweekly 3
getconf keepmonthly 1

getconf srcdir /var/maildir
getconf destdir
getconf desthost
getconf destport 22
getconf destuser

getconf multiconnection notset

letters="a b c d e f g h i j k l m n o p q r s t u v w x y z"
failedcount=0
# strip trailing /
destdir=${destdir%/}
srcdir=${srcdir%/}

[ -d $srcdir ] || fatal "source directory $srcdir doesn't exist"

[ "$multiconnection" == "notset" ] && fatal "The maildir handler uses a very different destination format. See the example .maildir for more information"

[ ! $test ] || testflags="--dry-run -v"
rsyncflags="$testflags -e 'ssh -p $destport' -r -v --ignore-existing --delete --size-only --bwlimit=$speedlimit"
excludes="--exclude '.Trash/\*' --exclude '.Mistakes/\*' --exclude '.Spam/\*'"

##################################################################
### FUNCTIONS

function do_user() {
	local user=$1
	local btype=$2
	local letter=${user:0:1}
	local source="$srcdir/$letter/$user/"
	local target="$destdir/$letter/$user/$btype.1"
	if [ ! -d $source ]; then
	  warning "maildir $source not found"
	  return
    fi

	debug "syncing"
	ret=`$RSYNC -e "ssh -p $destport" -r \
		--links --ignore-existing --delete --size-only --bwlimit=$speedlimit \
		--exclude '.Trash/*' --exclude '.Mistakes/*' --exclude '.Spam/*' \
		$source $destuser@$desthost:$target \
		2>&1`
	ret=$?
	# ignore 0 (success) and 24 (file vanished before it could be copied)
	if [ $ret != 0 -a $ret != 24 ]; then
		warning "rsync $user failed"
		warning "  returned: $ret"
		let "failedcount = failedcount + 1"
		if [ $failedcount -gt 100 ]; then
			fatal "100 rsync errors -- something is not working right. bailing out."
		fi
	fi
	ssh -o PasswordAuthentication=no $desthost -l $destuser "date +%c%n%s > $target/created"
}

# remove any maildirs from backup which might have been deleted
# and add new ones which have just been created.
# (actually, it just moved them to the directory "deleted")

function do_remove() {
	local tmp1=`maketemp maildir-tmp-file`
	local tmp2=`maketemp maildir-tmp-file`
	
	ssh -p $destport $destuser@$desthost mkdir -p "$destdir/deleted"
	for i in a b c d e f g h i j k l m n o p q r s t u v w x y z; do
		ls -1 "$srcdir/$i/" | sort > $tmp1
		ssh -p $destport $destuser@$desthost ls -1 "$destdir/$i/" | sort > $tmp2
		for deluser in `join -v 2 $tmp1 $tmp2`; do
			[ "$deluser" != "" ] || continue
			info "removing $destuser@$desthost:$destdir/$i/$deluser/"
			ssh -p $destport $destuser@$desthost mv "$destdir/$i/$deluser/" "$destdir/deleted"
		done
	done
	rm $tmp1
	rm $tmp2
}

function do_rotate() {
	[ "$rotate" == "yes" ] || return;
	local user=$1
	local letter=${user:0:1}
	local backuproot="$destdir/$letter/$user"
(
	ssh -T -o PasswordAuthentication=no $desthost -l $destuser <<EOF
##### BEGIN REMOTE SCRIPT #####
	seconds_daily=86400
	seconds_weekly=604800
	seconds_monthly=2628000
	keepdaily=$keepdaily
	keepweekly=$keepweekly
	keepmonthly=$keepmonthly
	now=\`date +%s\`

	if [ ! -d "$backuproot" ]; then
		echo "Debug: skipping rotate of $user. $backuproot doesn't exist."
		exit
	fi
	for rottype in daily weekly monthly; do
		seconds=\$((seconds_\${rottype}))

		dir="$backuproot/\$rottype"
		if [ ! -d \$dir.1 ]; then
			echo "Debug: \$dir.1 does not exist, skipping."
			continue 1
		elif [ ! -f \$dir.1/created ]; then
			echo "Warning: \$dir.1/created does not exist. This backup may be only partially completed. Skipping rotation."
			continue 1
		fi
		
		# Rotate the current list of backups, if we can.
		oldest=\`find $backuproot -type d -maxdepth 1 -name \$rottype'.*' | @SED@ 's/^.*\.//' | sort -n | tail -1\`
		#echo "Debug: oldest \$oldest"
		[ "\$oldest" == "" ] && oldest=0
		for (( i=\$oldest; i > 0; i-- )); do
			if [ -d \$dir.\$i ]; then
				if [ -f \$dir.\$i/created ]; then
					created=\`tail -1 \$dir.\$i/created\`
				else
					created=0
				fi
				cutoff_time=\$(( now - (seconds*(i-1)) ))
				if [ ! \$created -gt \$cutoff_time ]; then
					next=\$(( i + 1 ))
					if [ ! -d \$dir.\$next ]; then
						echo "Debug: \$rottype.\$i --> \$rottype.\$next"
						mv \$dir.\$i \$dir.\$next
						date +%c%n%s > \$dir.\$next/rotated
					else
						echo "Debug: skipping rotation of \$dir.\$i because \$dir.\$next already exists."
					fi
				else
					echo "Debug: skipping rotation of \$dir.\$i because it was created" \$(( (now-created)/86400)) "days ago ("\$(( (now-cutoff_time)/86400))" needed)."
				fi
			fi
		done
	done

	max=\$((keepdaily+1))
	if [ \( \$keepweekly -gt 0 -a -d $backuproot/daily.\$max \) -a ! -d $backuproot/weekly.1 ]; then
		echo "Debug: daily.\$max --> weekly.1"
		mv $backuproot/daily.\$max $backuproot/weekly.1
		date +%c%n%s > $backuproot/weekly.1/rotated
	fi

	max=\$((keepweekly+1))
	if [ \( \$keepmonthly -gt 0 -a -d $backuproot/weekly.\$max \) -a ! -d $backuproot/monthly.1 ]; then
		echo "Debug: weekly.\$max --> monthly.1"
		mv $backuproot/weekly.\$max $backuproot/monthly.1
		date +%c%n%s > $backuproot/monthly.1/rotated
	fi

	for rottype in daily weekly monthly; do
		max=\$((keep\${rottype}+1))
		dir="$backuproot/\$rottype"
		oldest=\`find $backuproot -type d -maxdepth 1 -name \$rottype'.*' | @SED@ 's/^.*\.//' | sort -n | tail -1\`
		[ "\$oldest" == "" ] && oldest=0 
		# if we've rotated the last backup off the stack, remove it.
		for (( i=\$oldest; i >= \$max; i-- )); do
			if [ -d \$dir.\$i ]; then
				if [ -d $backuproot/rotate.tmp ]; then
					echo "Debug: removing rotate.tmp"
					rm -rf $backuproot/rotate.tmp
				fi
				echo "Debug: moving \$rottype.\$i to rotate.tmp"
				mv \$dir.\$i $backuproot/rotate.tmp
			fi
		done
	done
####### END REMOTE SCRIPT #######
EOF
) | (while read a; do passthru $a; done)

}


function setup_remote_dirs() {
	local user=$1
	local backuptype=$2
	local letter=${user:0:1}
	local dir="$destdir/$letter/$user/$backuptype"
	local tmpdir="$destdir/$letter/$user/rotate.tmp"
(
	ssh -T -o PasswordAuthentication=no $desthost -l $destuser <<EOF
		if [ ! -d $destdir ]; then
			echo "Fatal: Destination directory $destdir does not exist on host $desthost."
			exit 1
		elif [ -d $dir.1 ]; then
			if [ -f $dir.1/created ]; then
				echo "Warning: $dir.1 already exists. Overwriting contents."
			else
				echo "Warning: we seem to be resuming a partially written $dir.1"
			fi
		else
			if [ -d $tmpdir ]; then
				mv $tmpdir $dir.1
				if [ \$? == 1 ]; then
					echo "Fatal: could mv $destdir/rotate.tmp $dir.1 on host $desthost"
					exit 1
				fi
			else
				mkdir --parents $dir.1
				if [ \$? == 1 ]; then
					echo "Fatal: could not create directory $dir.1 on host $desthost"
					exit 1
				fi
			fi
			if [ -d $dir.2 ]; then
				echo "Debug: update links $backuptype.2 --> $backuptype.1"
				cp -alf $dir.2/. $dir.1
				#if [ \$? == 1 ]; then
				#	echo "Fatal: could not create hard links to $dir.1 on host $desthost"
				#	exit 1
				#fi
			fi
		fi
		[ -f $dir.1/created ] && rm $dir.1/created
		[ -f $dir.1/rotated ] && rm $dir.1/rotated
		exit 0
EOF
) | (while read a; do passthru $a; done)

	if [ $? == 1 ]; then exit; fi
}

function start_mux() {
	if [ "$multiconnection" == "yes" ]; then
		debug "Starting dummy ssh connection"
		ssh -p $destport $destuser@$desthost sleep 1d &
        sleep 1
	fi
}

function end_mux() {
	if [ "$multiconnection" == "yes" ]; then
		debug "Stopping dummy ssh connection"
		ssh -p $destport $destuser@$desthost pkill sleep
	fi
}

###
##################################################################

# see if we can login
debug "ssh -o PasswordAuthentication=no $desthost -l $destuser 'echo -n 1'"
if [ ! $test ]; then
	result=`ssh -o PasswordAuthentication=no $desthost -l $destuser 'echo -n 1' 2>&1`
	if [ "$result" != "1" ]; then
		fatal "Can't connect to $desthost as $destuser."
	fi
fi

end_mux
start_mux

## SANITY CHECKS ##
status=`ssh -p $destport $destuser@$desthost "[ -d \"$destdir\" ] && echo 'ok'"`
if [ "$status" != "ok" ]; then
	end_mux
	fatal "Destination directory $destdir doesn't exist!"
    exit
fi

### REMOVE OLD MAILDIRS ###

if [ "$remove" == "yes" ]; then
	do_remove
fi

### MAKE BACKUPS ###

if [ "$backup" == "yes" ]; then
	if [ $keepdaily -gt 0 ]; then btype=daily
	elif [ $keepweekly -gt 0 ]; then btype=weekly
	elif [ $keepmonthly -gt 0 ]; then btype=monthly
	else fatal "keeping no backups"; fi
	
	if [ "$testuser" != "" ]; then
		cd "$srcdir/${user:0:1}"
		do_rotate $testuser
		setup_remote_dirs $testuser $btype
		do_user $testuser $btype
	else
		for i in $letters; do
			[ -d "$srcdir/$i" ] || fatal "directory $srcdir/$i not found."
			cd "$srcdir/$i"
			debug $i
			for user in `ls -1`; do
				[ "$user" != "" ] || continue
				debug $user
				do_rotate $user
				setup_remote_dirs $user $btype
				do_user $user $btype
			done
		done
	fi
fi

end_mux