[Unit]
Description=Backup for Container Volume %I

[Service]
Type=oneshot
SyslogIdentifier=%N
ExecStartPre=/bin/install --mode 0700 --directory %S/backups/coreos-home-server/%i
ExecStart=/bin/podman run --replace --rm --name %p-%i --entrypoint /bin/bash \
                          --volume %i:/data:z,ro \
                          --volume %S/backups/coreos-home-server/%i:/backup:z \
                          docker.io/debian:bullseye-slim -c \
                          'test -f /backup/%i-latest.tar.gz && \
                           test "$(find /data -type f -newer /backup/%i-latest.tar.gz -print -quit | wc -l)" -eq 0 && exit 0; \
                           name="%i-$(date +%%w%%H)" && \
                           tar --verbose --create --gzip --file "/backup/$name.tar.gz" --directory /data . && \
                           cd /backup && ln --symbolic --force "$name.tar.gz" %i-latest.tar.gz'

[Install]
WantedBy=multi-user.target