chore: flatten module structure

modules/image/builder.nix

@@ -0,0 +1,183 @@
+{
+  config,
+  lib,
+  options,
+  pkgs,
+  ...
+}:
+let
+  inherit (pkgs.stdenv.hostPlatform) efiArch;
+
+  initialPartitions = {
+    "10-root" = {
+      storePaths = [ config.system.build.toplevel ];
+      repartConfig = {
+        Type = "root";
+        Minimize = "best";
+        Format = "erofs";
+        MakeDirectories = "/home /root /etc /dev /sys /bin /var /proc /run /usr /srv /tmp /mnt /lib /efi";
+        Verity = "data";
+        VerityMatchKey = "root";
+        SplitName = "root";
+      };
+    };
+
+    "20-root-verity" = {
+      repartConfig = {
+        Type = "root-verity";
+        Minimize = "best";
+        Verity = "hash";
+        VerityMatchKey = "root";
+        SplitName = "verity";
+      };
+    };
+  };
+
+  # TODO: We don't need a combined image here - add dry-run flag to repart invocation
+  verityRepart = import (pkgs.path + "/nixos/lib/eval-config.nix") {
+    inherit lib pkgs;
+    system = null;
+    modules = [
+      (
+        { modulesPath, ... }:
+        {
+          imports = [ (modulesPath + "/image/repart.nix") ];
+          image.repart = {
+            name = "verity";
+            split = true;
+            mkfsOptions = lib.mkIf config.image.compress {
+              erofs = [
+                "-zlz4hc,level=12"
+                "-Efragments,dedupe,ztailpacking"
+              ];
+            };
+            partitions = initialPartitions;
+          };
+        }
+      )
+    ];
+  };
+
+  rootPart = "${verityRepart.config.system.build.image}/${verityRepart.config.image.repart.imageFileBasename}.root.raw";
+  verityPart = "${verityRepart.config.system.build.image}/${verityRepart.config.image.repart.imageFileBasename}.verity.raw";
+
+  verityImgAttrs = builtins.fromJSON (
+    builtins.readFile "${verityRepart.config.system.build.image}/repart-output.json"
+  );
+  rootAttrs = builtins.elemAt verityImgAttrs 0;
+  verityAttrs = builtins.elemAt verityImgAttrs 1;
+
+  rootUuid = rootAttrs.uuid;
+  verityUuid = verityAttrs.uuid;
+  verityRootHash = rootAttrs.roothash;
+
+  finalPartitions = {
+    "10-esp" = {
+      contents = {
+        "/EFI/BOOT/BOOT${lib.toUpper efiArch}.EFI".source = "${pkgs.systemdUkify}/lib/systemd/boot/efi/systemd-boot${efiArch}.efi";
+        "/EFI/Linux/${config.system.boot.loader.ukiFile}".source = "${config.system.build.uki}/${config.system.boot.loader.ukiFile}";
+        "/default-ssh-authorized-keys.txt" = lib.mkIf config.system.image.sshKeys.enable {
+          source = pkgs.writeText "ssh-keys" (lib.concatStringsSep "\n" config.system.image.sshKeys.keys);
+        };
+      };
+      repartConfig = {
+        Type = "esp";
+        Format = "vfat";
+        SizeMinBytes = "96M";
+        SizeMaxBytes = "96M";
+        SplitName = "-";
+      };
+    };
+    "20-root-verity-a" = {
+      repartConfig = {
+        Type = "root-verity";
+        Label = "verity-${config.system.image.version}";
+        CopyBlocks = "${verityPart}";
+        SplitName = "-";
+        SizeMinBytes = "64M";
+        SizeMaxBytes = "64M";
+        UUID = "${verityUuid}";
+        ReadOnly = 1;
+      };
+    };
+    # TODO: Add signature partition for systemd-nspawn
+    "22-root-a" = {
+      repartConfig = {
+        Type = "root";
+        Label = "root-${config.system.image.version}";
+        CopyBlocks = "${rootPart}";
+        SplitName = "-";
+        UUID = "${rootUuid}";
+        ReadOnly = 1;
+      };
+    };
+  };
+
+  finalRepart = import (pkgs.path + "/nixos/lib/eval-config.nix") {
+    inherit lib pkgs;
+    system = null;
+    modules = [
+      (
+        { modulesPath, ... }:
+        {
+          imports = [ (modulesPath + "/image/repart.nix") ];
+          image.repart = {
+            name = "${config.system.image.id}";
+            partitions = finalPartitions;
+          };
+        }
+      )
+    ];
+  };
+
+in
+{
+
+  # This fields is immutable by default, but can be overridden.
+  options.system.nixos.codeName = lib.mkOption { readOnly = false; };
+  options.system.nixos.release = lib.mkOption { readOnly = false; };
+
+  # FIXME: Should be configured somehow
+  config.system.nixos = {
+    codeName = "Finn";
+    distroId = "patos";
+    distroName = "PatOS";
+    release = "2024-11";
+    variant_id = "server";
+    variantName = "Server";
+    vendorName = "PatOS";
+  };
+
+  options.image.compress = lib.mkEnableOption "image compression" // {
+    default = true;
+  };
+
+  config.system.build = {
+    inherit verityRootHash;
+
+    image =
+      (pkgs.linkFarm "image-release" [
+        {
+          name = "${config.system.image.id}_${config.system.image.version}.efi";
+          path = "${config.system.build.uki}/${config.system.boot.loader.ukiFile}";
+        }
+        {
+          name = "${config.system.image.id}_${config.system.image.version}_${verityUuid}.verity";
+          path = "${verityRepart.config.system.build.image}/${verityRepart.config.image.repart.imageFileBasename}.verity.raw";
+        }
+        {
+          name = "${config.system.image.id}_${config.system.image.version}_${rootUuid}.root";
+          path = "${verityRepart.config.system.build.image}/${verityRepart.config.image.repart.imageFileBasename}.root.raw";
+        }
+        {
+          name = "${config.system.image.id}_${config.system.image.version}.img";
+          path = "${finalRepart.config.system.build.image}/${finalRepart.config.image.repart.imageFileBasename}.raw";
+        }
+      ])
+      // {
+        imageFile = "${config.system.image.id}_${config.system.image.version}.img";
+      };
+
+  };
+
+}