Persist the nix-index index.

nix/configuration/configuration.nix

@@ -62,6 +62,7 @@
     ./roles/sm64ex
     ./roles/shipwright
     ./roles/2ship2harkinian
+    ./roles/nix_index
   ];
 
   nix.settings.experimental-features = [
@@ -147,7 +148,6 @@
     trace-cmd # ftrace
     tcpdump
     git-crypt
-    nix-index-unwrapped
     gnumake
     ncdu
     nix-tree

nix/configuration/hosts/odo/default.nix

@@ -47,6 +47,7 @@
   me.launch_keyboard.enable = true;
   me.lvfs.enable = true;
   me.media.enable = true;
+  me.nix_index.enable = true;
   me.python.enable = true;
   me.qemu.enable = true;
   me.rust.enable = true;

nix/configuration/roles/nix_index/default.nix

@@ -0,0 +1,44 @@
+{
+  config,
+  lib,
+  pkgs,
+  ...
+}:
+
+{
+  imports = [ ];
+
+  options.me = {
+    nix_index.enable = lib.mkOption {
+      type = lib.types.bool;
+      default = false;
+      example = true;
+      description = "Whether we want to install nix_index.";
+    };
+  };
+
+  config = lib.mkIf config.me.nix_index.enable (
+    lib.mkMerge [
+      {
+        environment.systemPackages = with pkgs; [
+          nix-index-unwrapped
+        ];
+
+        environment.persistence."/state" = lib.mkIf (!config.me.buildingIso) {
+          hideMounts = true;
+          users.talexander = {
+            directories = [
+              {
+                directory = ".cache/nix-index";
+                user = "talexander";
+                group = "talexander";
+                mode = "0755";
+              }
+            ];
+          };
+        };
+
+      }
+    ]
+  );
+}