From 6e67da9c6f3a4017db9ff0c1a557fc1d32c177ee Mon Sep 17 00:00:00 2001
From: Alexander Heldt <me@alexanderheldt.se>
Date: Sat, 27 Jul 2024 11:49:39 +0200
Subject: [PATCH] pinwheel: Automatically garbage collect generations

---
 hosts/pinwheel/modules/boot/default.nix | 42 +++++++++++++++++--------
 1 file changed, 29 insertions(+), 13 deletions(-)

diff --git a/hosts/pinwheel/modules/boot/default.nix b/hosts/pinwheel/modules/boot/default.nix
index b066383..861db08 100644
--- a/hosts/pinwheel/modules/boot/default.nix
+++ b/hosts/pinwheel/modules/boot/default.nix
@@ -1,21 +1,37 @@
-{ pkgs, ... }:
+{ inputs, pkgs, config, ... }:
 {
-  boot = {
-    kernelPackages = pkgs.linuxPackages_latest;
+  imports = [ inputs.nix-gc-env.nixosModules.default ];
 
-    kernel = {
-      sysctl = {
-        "fs.inotify.max_user_instances" = 1024; # default: 128
+  config = {
+    nix.gc = {
+      automatic = true;
+      dates = "weekly";
+
+      # `delete_generations` added by nix-gc-env
+      delete_generations = "+${builtins.toString config.boot.loader.systemd-boot.configurationLimit}";
+    };
+
+    boot = {
+      kernelPackages = pkgs.linuxPackages_latest;
+
+      kernel = {
+        sysctl = {
+          "fs.inotify.max_user_instances" = 1024; # default: 128
+        };
       };
-    };
 
-    loader = {
-      systemd-boot.enable = true;
-      efi.canTouchEfiVariables = true;
-    };
+      loader = {
+        systemd-boot = {
+          enable = true;
+          configurationLimit = 10;
+        };
 
-    initrd.secrets = {
-      "/crypto_keyfile.bin" = null;
+        efi.canTouchEfiVariables = true;
+      };
+
+      initrd.secrets = {
+        "/crypto_keyfile.bin" = null;
+      };
     };
   };
 }