From a0f67b3a10624e3fbc46f07c8bd0ae612a9a9348 Mon Sep 17 00:00:00 2001
From: Aly Raffauf <alyraffauf@gmail.com>
Date: Tue, 2 Apr 2024 02:08:25 -0400
Subject: [PATCH] rustboro: added initial impermanence settings

---
 flake.lock                                | 16 ++++++++
 flake.nix                                 |  5 ++-
 hosts/rustboro/default.nix                | 47 ++++++++++++++++++++++-
 hosts/rustboro/disko.nix                  |  4 +-
 hosts/rustboro/hardware-configuration.nix |  4 ++
 5 files changed, 72 insertions(+), 4 deletions(-)

diff --git a/flake.lock b/flake.lock
index 5e5e2fc6..a1cff91e 100644
--- a/flake.lock
+++ b/flake.lock
@@ -200,6 +200,21 @@
         "type": "github"
       }
     },
+    "impermanence": {
+      "locked": {
+        "lastModified": 1708968331,
+        "narHash": "sha256-VUXLaPusCBvwM3zhGbRIJVeYluh2uWuqtj4WirQ1L9Y=",
+        "owner": "nix-community",
+        "repo": "impermanence",
+        "rev": "a33ef102a02ce77d3e39c25197664b7a636f9c30",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-community",
+        "repo": "impermanence",
+        "type": "github"
+      }
+    },
     "nixos-hardware": {
       "locked": {
         "lastModified": 1711352745,
@@ -285,6 +300,7 @@
         "home-manager": "home-manager",
         "home-manager-unstable": "home-manager-unstable",
         "hyprland": "hyprland",
+        "impermanence": "impermanence",
         "nixos-hardware": "nixos-hardware",
         "nixpkgs": "nixpkgs_3",
         "nixpkgs-unstable": "nixpkgs-unstable"
diff --git a/flake.nix b/flake.nix
index 5b6bf64c..561cacd2 100644
--- a/flake.nix
+++ b/flake.nix
@@ -23,6 +23,8 @@
     disko-unstable.url = "github:nix-community/disko";
     disko-unstable.inputs.nixpkgs.follows = "nixpkgs-unstable";
 
+    impermanence.url = "github:nix-community/impermanence";
+
     # Latest Hyprland
     hyprland.url = "github:hyprwm/Hyprland";
 
@@ -40,7 +42,7 @@
   };
 
   outputs = inputs@{ nixpkgs, nixpkgs-unstable, home-manager
-    , home-manager-unstable, nixos-hardware, disko, disko-unstable, ... }: {
+    , home-manager-unstable, nixos-hardware, impermanence, disko, disko-unstable, ... }: {
 
       homeConfigurations.aly =
         home-manager-unstable.lib.homeManagerConfiguration {
@@ -92,6 +94,7 @@
           specialArgs = { inherit inputs; };
           modules = [
             disko-unstable.nixosModules.disko
+            impermanence.nixosModules.impermanence
             nixos-hardware.nixosModules.lenovo-thinkpad-t440p
             home-manager-unstable.nixosModules.home-manager
             ./hosts/rustboro
diff --git a/hosts/rustboro/default.nix b/hosts/rustboro/default.nix
index 828bdda0..c31d945f 100644
--- a/hosts/rustboro/default.nix
+++ b/hosts/rustboro/default.nix
@@ -1,6 +1,6 @@
 # Lenovo Thinkpad T440p with a Core i5 4210M, 16GB RAM, 512GB SSD.
 
-{ config, pkgs, ... }:
+{ config, lib, pkgs, ... }:
 
 {
   imports = [
@@ -13,6 +13,41 @@
     # Bootloader.
     loader.systemd-boot.enable = true;
     loader.efi.canTouchEfiVariables = true;
+
+    # initrd.postDeviceCommands = lib.mkAfter ''
+    #   mkdir /btrfs_tmp
+    #   mount /dev/sda2 /btrfs_tmp
+    #   if [[ -e /btrfs_tmp/rootfs ]]; then
+    #       mkdir -p /btrfs_tmp/old_roots
+    #       timestamp=$(date --date="@$(stat -c %Y /btrfs_tmp/rootfs)" "+%Y-%m-%-d_%H:%M:%S")
+    #       mv /btrfs_tmp/rootfs "/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 $(find /btrfs_tmp/old_roots/ -maxdepth 1 -mtime +10); do
+    #       delete_subvolume_recursively "$i"
+    #   done
+
+    #   btrfs subvolume create /btrfs_tmp/rootfs
+    #   umount /btrfs_tmp
+    # '';
+    initrd.postDeviceCommands = lib.mkAfter ''
+      mkdir /btrfs_tmp
+      mount /dev/sda2 /btrfs_tmp
+      if [[ -e /btrfs_tmp/rootfs ]]; then
+          btrfs subvolume delete /btrfs_tmp/rootfs
+      fi
+
+      btrfs subvolume create /btrfs_tmp/rootfs
+      umount /btrfs_tmp
+    '';
   };
 
   networking.hostName = "rustboro"; # Define your hostname.
@@ -40,5 +75,15 @@
   users.users.aly.hashedPassword =
     "$y$j9T$VdtiEyMOegHpcUwgmCVFD0$K8Ne6.zk//VJNq2zxVQ0xE0Wg3LohvAQd3Xm9aXdM15";
 
+  environment.persistence."/persist" = {
+    hideMounts = true;
+    directories = [
+      "/etc/NetworkManager/system-connections"
+    ];
+    files = [
+      "/etc/machine-id"
+    ];
+  };
+
   system.stateVersion = "23.11"; # Did you read the comment?
 }
diff --git a/hosts/rustboro/disko.nix b/hosts/rustboro/disko.nix
index e08fbac9..bd34b968 100644
--- a/hosts/rustboro/disko.nix
+++ b/hosts/rustboro/disko.nix
@@ -11,7 +11,7 @@
               priority = 1;
               name = "ESP";
               start = "1M";
-              end = "128M";
+              end = "512M";
               type = "EF00";
               content = {
                 type = "filesystem";
@@ -31,7 +31,7 @@
                   "rootfs" = { mountpoint = "/"; };
                   # For use with future impermanence setups
                   "persistent" = {
-                    mountpoint = "/persistent";
+                    mountpoint = "/persist";
                     mountOptions = [ "compress=zstd" ];
                   };
                   # Subvolume name is the same as the mountpoint
diff --git a/hosts/rustboro/hardware-configuration.nix b/hosts/rustboro/hardware-configuration.nix
index 68ecc84e..49bf1822 100644
--- a/hosts/rustboro/hardware-configuration.nix
+++ b/hosts/rustboro/hardware-configuration.nix
@@ -19,6 +19,10 @@
   boot.kernelModules = [ "kvm-intel" ];
   boot.extraModulePackages = [ ];
 
+  fileSystems."/persist" = {
+    neededForBoot = true;
+  };
+
   networking.useDHCP = lib.mkDefault true;
 
   nixpkgs.hostPlatform = lib.mkDefault "x86_64-linux";