Initial commit

modules/nixos/common/shared/nix.nix

@@ -0,0 +1,85 @@
+{
+  config,
+  lib,
+  pkgs,
+  ...
+}:
+
+let
+  inherit (lib)
+    mkDefault
+    optional
+    versionOlder
+    versions
+    ;
+in
+{
+  nix.package = mkDefault pkgs.nix;
+
+  # for `nix run synix#foo`, `nix build synix#bar`, etc
+  nix.registry = {
+    synix = {
+      from = {
+        id = "synix";
+        type = "indirect";
+      };
+      to = {
+        owner = "sid";
+        repo = "synix";
+        host = "git.sid.ovh";
+        type = "gitea";
+      };
+    };
+  };
+
+  # fallback quickly if substituters are not available.
+  nix.settings.connect-timeout = mkDefault 5;
+  nix.settings.fallback = true;
+
+  nix.settings.experimental-features = [
+    "nix-command"
+    "flakes"
+  ]
+  ++ optional (
+    config.nix.package != null && versionOlder (versions.majorMinor config.nix.package.version) "2.22"
+  ) "repl-flake";
+
+  nix.settings.log-lines = mkDefault 25;
+
+  # avoid disk full issues
+  nix.settings.max-free = mkDefault (3000 * 1024 * 1024);
+  nix.settings.min-free = mkDefault (512 * 1024 * 1024);
+
+  # avoid copying unnecessary stuff over SSH
+  nix.settings.builders-use-substitutes = true;
+
+  # workaround for https://github.com/NixOS/nix/issues/9574
+  nix.settings.nix-path = config.nix.nixPath;
+
+  nix.settings.download-buffer-size = 524288000; # 500 MiB
+
+  # add all wheel users to the trusted-users group
+  nix.settings.trusted-users = [
+    "@wheel"
+  ];
+
+  # binary caches
+  nix.settings.substituters = [
+    "https://cache.nixos.org"
+    "https://nix-community.cachix.org"
+    "https://cache.garnix.io"
+    "https://numtide.cachix.org"
+  ];
+  nix.settings.trusted-public-keys = [
+    "cache.nixos.org-1:6NCHdD59X431o0gWypbMrAURkbJ16ZPMQFGspcDShjY="
+    "nix-community.cachix.org-1:mB9FSh9qf2dCimDSUo8Zy7bkq5CX+/rkCWyvRCYg3Fs="
+    "cache.garnix.io:CTFPyKSLcx5RMJKfLo5EEPUObbA78b0YQ2DTCJXqr9g="
+    "numtide.cachix.org-1:2ps1kLBUWjxIneOy1Ik6cQjb41X0iXVXeHigGmycPPE="
+  ];
+
+  nix.gc = {
+    automatic = true;
+    dates = "weekly";
+    options = "--delete-older-than 30d";
+  };
+}