backup wrapper for borg backup

backup.sh

#!/bin/bash
set -eu -o pipefail

# -----------------------------------------------------------------------------

export LANG=en_US.UTF-8
export BORG_PASSPHRASE=''

MAIN_USER="johndoe"
MAIN_HOMEDIR="$(getent passwd ${MAIN_USER} | cut -f 6 -d ':')"
EXCLUDE_FILE="${MAIN_HOMEDIR}/.borg/exclude"
REPOSITORY="/var/backups/mybackup/"
REMOTE_SOURCE="/media/remotefs/backups/mybackup/"

LOCK_WAIT=120
CHECKPOINT_EVERY=120
COMPRESSION="zlib,9"
KEEP_WITHIN="3d"
KEEP_DAILY="7"
KEEP_WEEKLY="4"
KEEP_MONTHLY="3"
KEEP_YEARLY="1"

LOCK_WRITE="flock --exclusive ${REPOSITORY}"
LOCK_READ="flock --shared ${REPOSITORY}"

CMD="sudo -E -u ${MAIN_USER} -- borg"
WCMD="${LOCK_WRITE} ${CMD}"
RCMD="${LOCK_READ} ${CMD}"
SYNC="${LOCK_READ} rsync -azP --delete-delay"
DEFAULT_OPTS="--lock-wait ${LOCK_WAIT} --error"

# -----------------------------------------------------------------------------

borg_create() {
    local prefix="$1"
    local source_path="$2"
    local backup_name="${prefix}_$(date --utc '+%Y.%m.%d-%H')"

    ${WCMD} create ${DEFAULT_OPTS}                      \
              --checkpoint-interval ${CHECKPOINT_EVERY} \
              --compression         ${COMPRESSION}      \
              --exclude-from        "${EXCLUDE_FILE}"   \
              --exclude-if-present  ".duplicity-ignore" \
              --one-file-system                         \
              --exclude-caches                          \
          "${REPOSITORY}::${backup_name}" "${source_path}" || :
    fix_owner
}

borg_check() {
    ${WCMD} check ${DEFAULT_OPTS} "$REPOSITORY"
    fix_owner
}

borg_list() {
    ${RCMD} list ${DEFAULT_OPTS} "${REPOSITORY}"
}

borg_delete() {
    local target="$1"

    ${WCMD} delete ${DEFAULT_OPTS} \
            --progress --stats \
        "${REPOSITORY}::${target}"
    fix_owner
}

borg_prune() {
    local keep_within="${1:-${KEEP_WITHIN}}"
    local keep_daily="${2:-${KEEP_DAILY}}"
    local keep_weekly="${3:-${KEEP_WEEKLY}}"
    local keep_monthly="${4:-${KEEP_MONTHLY}}"
    local keep_yearly="${5:-${KEEP_YEARLY}}"

    ${WCMD} prune ${DEFAULT_OPTS}            \
            --keep-within  "${keep_within}"  \
            --keep-daily   "${keep_daily}"   \
            --keep-weekly  "${keep_weekly}"  \
            --keep-monthly "${keep_monthly}" \
            --keep-yearly  "${keep_yearly}"  \
        "${REPOSITORY}"
    fix_owner
}

borg_info() {
    local target="$1"

    ${RCMD} info ${DEFAULT_OPTS} "${REPOSITORY}::${target}"
}

backup_sync() {
    ${SYNC} "${REPOSITORY}" "${REMOTE_SOURCE}"
}

fix_owner() {
    ${LOCK_WRITE} sudo chown -R ${MAIN_USER}:${MAIN_USER} "${REPOSITORY}"
}

print_help() {
    echo "$(basename $0) is a small wrapper around Borg backup."
    echo "https://borgbackup.readthedocs.io"
    echo
    echo "Settings:"
    echo "  MAIN_USER        $(printf "%-40s (%s)" "${MAIN_USER}" $(getent passwd | cut -f 1 -d ':' | grep -q "${MAIN_USER}" && echo -n "ok" || echo -n "not ok"))"
    echo "  MAIN_HOMEDIR     $(printf "%-40s (%s)" "${MAIN_HOMEDIR}" $([ -d "${MAIN_HOMEDIR}" ] && echo -n "ok" || echo -n "not ok"))"
    echo "  REPOSITORY       $(printf "%-40s (%s)" "${REPOSITORY}" $([ -d "${REPOSITORY}" ] && echo -n "ok" || echo -n "not ok"))"
    echo "  EXCLUDE_FILE     $(printf "%-40s (%s)" "${EXCLUDE_FILE}" $([ -r "${EXCLUDE_FILE}" ] && echo -n "ok" || echo -n "not ok"))"
    echo "  REMOTE_SOURCE    $(printf "%-40s (%s)" "${REMOTE_SOURCE}" $([ -d "${REMOTE_SOURCE}" ] && echo -n "ok" || echo -n "not ok"))"
    echo "  BORG_PASSPHRASE  $(printf "%-40s (%s)" " " $([ ! -z "${BORG_PASSPHRASE}" ] && echo -n "ok" || echo -n "not ok"))"
    echo
    echo "Commands available:"
    echo "  create    Creates new archive in repository. Backups $HOME and /etc."
    echo "  check     Checks repository for consistency."
    echo "  list      List available snapshots."
    echo "  delete    Removes a snapshot."
    echo "              - the name of the snapshot."
    echo "  prune     Prunes old snapshots."
    echo "              - How long to keep all snapshots. Default is $KEEP_WITHIN."
    echo "              - How many daily snapshots to keep. Default is $KEEP_DAILY."
    echo "              - How many weekly snapshots to keep. Default is $KEEP_WEEKLY."
    echo "              - How many monthly snapshots to keep. Default is $KEEP_MONTHLY."
    echo "              - How many yearly snapshots to keep. Default is $KEEP_YEARLY."
    echo "  info      Print information about snapshot."
    echo "              - the name of the snapshot."
    echo "  sync      Sync local backup with remote one."
    echo "  help      Print this message."
}

# -----------------------------------------------------------------------------

if [[ $# -eq 0 ]] ; then
    OPTION=""
else
    OPTION="$1"
    shift
fi

case "${OPTION}" in
    create)
        borg_create home "${MAIN_HOMEDIR}"
        borg_create etc  /etc
        ;;
    check)
        borg_check "$@"
        ;;
    list)
        borg_list "$@"
        ;;
    delete)
        borg_delete "$@"
        ;;
    prune)
        borg_prune "$@"
        ;;
    info)
        borg_info "$@"
        ;;
    sync)
        backup_sync "$@"
        ;;
    help)
        print_help
        ;;
    *)
        print_help
        exit 1
        ;;
esac

# -----------------------------------------------------------------------------

unset BORG_PASSPHRASE