Backup script for use with backup2swift

backup.service

[Unit]
Description=Run backup script

[Service]
Type=oneshot
ExecStart=/bin/bash -c 'PATH=/opt/bin:$PATH /opt/bin/backup.sh /etc/systemd/system /opt/bin'

backup.sh

#!/bin/bash
# (c) The University of Queensland 2017
# MIT Licensed (https://opensource.org/licenses/MIT)

set -e

TIMESTAMP=$(date +'%Y%m%dT%H%M%S')
KEEP_SECS=$(expr 7 '*' 24 '*' 60 '*' 60 )
# If today is Sunday
if [[ $(date +'%w') == '0' ]]; then
        # Keep backups for four weeks
        KEEP_SECS=$(expr 4 '*' 7 '*' 24 '*' 60 '*' 60 )
        # On every fouth Sunday
        if [[ $(expr $(date +'%W') % 4) == '0' ]]; then
                # Keep backups for a year
                KEEP_SECS=$(expr 365 '*' 24 '*' 60 '*' 60 )
        fi
fi

for DIR in "$@"
do
        NAME=$(basename $DIR)
        BASEDIR=$(dirname $DIR)
        DEST=/var/backup/${TIMESTAMP}-${NAME}.tar
        tar cf "$DEST" -C "$BASEDIR" "$NAME"
        backup2swift backup -c /var/backup/config.json --delete-after $KEEP_SECS "$DEST"
        rm "$DEST"
done

backup.timer

[Unit]
Description=Run backup script

[Timer]
OnCalendar=*-*-* 16:00:00

[Install]
WantedBy=timers.target