backup.nix

backup.nix

{ config, pkgs, ... }:

let
  uuid = "91434e29-edf5-42b7-b339-43d3a1d58359";
  backup = pkgs.writeScript "usb-backup.sh" ''
   #!/bin/sh

   export DISPLAY=:0.0
   SECONDS=0

   /run/wrappers/bin/su -l -c 'notify-send "Backup starting ..." -u critical' ielectric

   mount -v /dev/disk/by-uuid/${uuid} /mnt/usb

   # https://borgbackup.readthedocs.io/en/stable/quickstart.html#automating-backups
   # SETUP: borg init /mnt/usb/guava
   export BORG_PASSPHRASE=<insert>
   borg create --compression lz4 -v --stats /mnt/usb/guava::'{hostname}-{now}' /etc/ /nix/var/ /home/ielectric/ --exclude '*.stack-work*'
   borg prune -v --list /mnt/usb/guava --prefix '{hostname}-' --keep-daily=7 --keep-weekly=4 --keep-monthly=6

   umount -v /dev/disk/by-uuid/${uuid}

   /run/wrappers/bin/su -l -c "notify-send \"Backup DONE in $SECONDS seconds\" -u critical" ielectric
   echo "done."
  '';
in {
  systemd.services.backup-usb = {
    description = "Backup to USB";
    path = with pkgs; [borgbackup utillinux];

    serviceConfig = {
      Type                    = "oneshot";
      Nice                    = 10;
      ExecStart               = backup;
    };
  };
  environment.systemPackages = [ pkgs.libnotify ];
  services.udev.extraRules = ''
    ACTION=="add", ENV{ID_FS_UUID}=="${uuid}", RUN+="${pkgs.systemd}/bin/systemctl start backup-usb"
  '';
}