machine_setup/nix/configuration/roles/zfs/default.nix

{
  config,
  lib,
  pkgs,
  ...
}:

let
  zfs_clone_send =
    (pkgs.writeScriptBin "zfs_clone_send" (builtins.readFile ./files/zfs_clone_send.bash)).overrideAttrs
      (old: {
        buildCommand = "${old.buildCommand}\n patchShebangs $out";

      });
  zfs_clone_recv =
    (pkgs.writeScriptBin "zfs_clone_recv" (builtins.readFile ./files/zfs_clone_recv.bash)).overrideAttrs
      (old: {
        buildCommand = "${old.buildCommand}\n patchShebangs $out";

      });
  zfs_clone_resume =
    (pkgs.writeScriptBin "zfs_clone_resume" (builtins.readFile ./files/zfs_clone_resume.bash))
    .overrideAttrs
      (old: {
        buildCommand = "${old.buildCommand}\n patchShebangs $out";

      });
in
{
  imports = [ ];

  options.me = {
    zfs.enable = lib.mkOption {
      type = lib.types.bool;
      default = false;
      example = true;
      description = "Whether we want to install zfs.";
    };
  };

  config = lib.mkIf config.me.zfs.enable {
    # Technically only needed when building the ISO because nix detects ZFS in the filesystem list normally. I basically always want this so I'm just setting it to always be on.
    boot.supportedFilesystems.zfs = true;

    boot.zfs.devNodes = "/dev/disk/by-partuuid";

    services.zfs = {
      autoScrub = {
        enable = true;
        interval = "monthly";
      };
      trim.enable = true;
    };

    environment.systemPackages = [
      zfs_clone_send
      zfs_clone_recv
      zfs_clone_resume
    ];

    environment.persistence."/persist" = lib.mkIf (config.me.mountPersistence) {
      hideMounts = true;
      directories = [
        "/etc/zfs/zpool.cache" # Which zpools to import, the root zpool is already imported and does not need this cache file but this captures additional pools.
      ];
    };
  };
}