Numbus/modules/common/hardware/disks/mirror.nix

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

with lib;

let
  cfg = config.numbus.hardware.disks;

  contentCount = builtins.length cfg.content.list;
  parityCount = builtins.length cfg.parity.list;

  dataMirror = {
    disko.devices.disk = listToAttrs (imap0 (i: device: {
      name = "mirror-${toString i}";
      value = {
        type = "disk";
        inherit device;
        content = {
          type = cfg.partitionTableScheme;
          partitions.raid = {
            size = cfg.content.partition.size;
            content = {
              type = "mdraid";
              name = "mirror";
            };
          };
        };
      };
    }) (cfg.content.list ++ cfg.parity.list));

    disko.devices.mdadm.mirror = {
      type = "mdadm";
      level = 1;
      content = {
        type = "luks";
        name = "mirror";
        settings.keyFile = "/run/secrets/disks/mirror";
        initrdUnlock = false;
        content = {
          type = "filesystem";
          format = cfg.content.partition.filesystem;
          mountpoint = "/mnt/data";
          mountOptions = [ "noauto" "nofail" ];
        };
      };
    };
  };
in

{
  config = mkIf (contentCount == 1 && parityCount == 1) (mkMerge [
    dataMirror
    {
      systemd.services.mount-mirror = {
        description = "Mount the disks mirror.";
        before = [ "mnt-data.mount" ];
        requiredBy = [ "mnt-data.mount" ];
        requires = [ "sops-install-secrets.service" ];
        path = [ pkgs.cryptsetup pkgs.util-linux ];
        serviceConfig = {
          Type = "oneshot";
          RemainAfterExit = true;
        };
        script = ''
          if [ ! -e /dev/mapper/mirror ]; then
            cryptsetup open /dev/md/mirror mirror --key-file /run/secrets/disks/mirror
          fi
          mkdir -p /mnt/data
          if ! mountpoint -q /mnt/data; then
            mount -t ${cfg.content.partition.filesystem} /dev/mapper/mirror /mnt/data
          fi
        '';
      };
    }
  ]);
}