Restic Cron Script

restic-backup.sh

#!/bin/bash
# Adapted from https://github.com/erikw/restic-systemd-automatic-backup/blob/master/usr/local/sbin/restic_backup.sh

set -e -o pipefail

export PATH="/bin:/usr/bin:/usr/local/bin"

RESTIC="/usr/local/bin/restic"
RESTIC_ENV="${HOME}/.restic.env"
BACKUP_TAG='cron'
BACKUP_PATH="${HOME}/Documents"

# How many backups to keep.
RETENTION_HOURS=72
RETENTION_DAYS=14
RETENTION_WEEKS=4
RETENTION_YEARS=1

source "$RESTIC_ENV"

exit_hook() {
    echo 'In exit_hook(), being killed' >&2
    jobs -p | xargs kill
    restic unlock
}
trap exit_hook INT TERM

# NOTE start all commands in background and wait for them to finish.
# Reason: bash ignores any signals while child process is executing and thus my trap exit hook is not triggered.
# However if put in subprocesses, wait(1) waits until the process finishes OR signal is received.
# Reference: https://unix.stackexchange.com/questions/146756/forward-sigterm-to-child-in-bash

echo "Starting backup at $(date)"

$RESTIC unlock &
wait $!

$RESTIC backup --verbose --tag "$BACKUP_TAG" "$BACKUP_PATH" &
wait $!

$RESTIC forget --verbose --tag "$BACKUP_TAG" --prune --keep-hourly $RETENTION_HOURS --keep-daily $RETENTION_DAYS --keep-weekly $RETENTION_WEEKS --keep-yearly $RETENTION_YEARS &
wait $!

echo "Backup and cleanup is done at $(date)"