feat(cache): implement nixos substituter (#62)

Author: jim3692

flake.nix

@@ -1,5 +1,10 @@
 {
   inputs = {
+    cache-server = {
+      flake = false;
+      url = "github:icedos/cache-server";
+    };
+
     nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
   };
 

modules/cache.nix

@@ -0,0 +1,18 @@
+{ config, lib, ... }:
+
+let
+  inherit (lib) mkIf;
+
+  inherit (config.icedos.system.cache)
+    enable
+    key
+    url
+    priority
+    ;
+in
+{
+  nix.settings = mkIf enable {
+    substituters = [ "${url}?priority=${toString priority}" ];
+    trusted-public-keys = [ key ];
+  };
+}

modules/options.nix

@@ -6,7 +6,7 @@
 }:
 
 let
-  inherit (lib) types;
+  inherit (lib) readFile types;
 
   inherit (icedosLib)
     mkBoolOption
@@ -90,6 +90,17 @@ in
           resolution = mkStrOption { default = "1920x1080"; };
         };
 
+        cache = {
+          enable = mkBoolOption { default = true; };
+          url = mkStrOption { default = "https://icedos.mirrors.knp.one/icedos"; };
+
+          key = mkStrOption {
+            default = readFile "${inputs.icedos-core.inputs.cache-server}/nix-public.pem";
+          };
+
+          priority = mkNumberOption { default = 100; };
+        };
+
         channels = mkSubmoduleListOption { default = [ ]; } {
           name = mkStrOption { };
           url = mkStrOption { };