first commit

hosts/T14p/impermanence.nix

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+{ lib, ... }: 
+let
+  impermanence =  builtins.fetchTarball "https://github.com/nix-community/impermanence/archive/master.tar.gz";
+in
+{
+  boot.initrd.postResumeCommands = lib.mkAfter ''
+    mkdir /btrfs_tmp
+    mount /dev/mapper/crypted /btrfs_tmp
+    if [[ -e /btrfs_tmp/@root ]]; then
+        mkdir -p /btrfs_tmp/@old_roots
+        timestamp=$(date --date="@$(stat -c %Y /btrfs_tmp/root)" "+%Y-%m-%-d_%H:%M:%S")
+        mv /btrfs_tmp/@root "/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/@root
+    umount /btrfs_tmp
+  '';
+
+  imports = [ "${impermanence}/nixos.nix" ];
+
+  environment.persistence."/persist" = {
+    enable = true;
+    hideMounts = true;
+    directories = [
+      "/var/log"
+      "/var/lib/bluetooth"
+      "/var/lib/nixox"
+      "/var/lib/systemd/coredump"
+      "/etc/NetworkManager/system-connections"
+    ];
+    files = [
+      "/etc/machine-id"
+    ];
+    users.louis = {
+      directories = [
+        "Documents"
+	"Downloads"
+      ];
+    };
+  };
+
+  fileSystems."/persist".neededForBoot = true;
+
+}