56 lines
1.6 KiB
Nix

{
options,
config,
lib,
inputs,
...
}:
with lib;
with lib.frajul; let
cfg = config.impermanence;
in {
imports = with inputs; [
impermanence.nixosModules.impermanence
persist-retro.nixosModules.persist-retro
];
options.impermanence = with types; {
enable = mkBoolOpt false "Enable impermanence";
removeTmpFilesOlderThan = mkOpt int 14 "Number of days to keep old btrfs_tmp files";
};
options.environment = with types; {
persist = mkOpt attrs {} "Files and directories to persist in the home";
};
config = {
# This script does the actual wipe of the system
# So if it doesn't run, the btrfs system effectively acts like a normal system
boot.initrd.postDeviceCommands = mkIf cfg.enable (lib.mkAfter ''
mkdir /btrfs_tmp
mount /dev/pool/root /btrfs_tmp
if [[ -e /btrfs_tmp/root ]]; then
mkdir -p /btrfs_tmp/old_roots
timestamp=$(date --date="@$(stat -c %Y /btrfs_tmp/root)" "+%Y-%m-%-d_%H:%M:%S")
mv /btrfs_tmp/root "/btrfs_tmp/old_roots/$timestamp"
fi
delete_subvolume_recursively() {
IFS=$'\n'
for i in $(btrfs subvolume list -o "$1" | cut -f 9- -d ' '); do
delete_subvolume_recursively "/btrfs_tmp/$i"
done
btrfs subvolume delete "$1"
}
for i in $(find /btrfs_tmp/old_roots/ -maxdepth 1 -mtime +${builtins.toString cfg.removeTmpFilesOlderThan}); do
delete_subvolume_recursively "$i"
done
btrfs subvolume create /btrfs_tmp/root
umount /btrfs_tmp
'');
environment.persistence."/persist" = mkIf cfg.enable (mkAliasDefinitions options.environment.persist);
};
}