switch-prebuilt: init

ops/nixos/lib/common.nix

@@ -5,6 +5,8 @@
 { pkgs, config, depot, lib, rebuilder, ... }@args:
 let 
   inherit (lib) mkDefault;
+
+  switch-prebuilt = import ./switch-prebuilt.nix args;
 in
 {
   imports = [ ../../../third_party/home-manager/nixos ];
@@ -60,6 +62,7 @@ in
       (mercurial.overridePythonAttrs (origAttrs: {
         propagatedBuildInputs = [python3Packages.hg-evolve depot.nix.pkgs.hg-git];
       }))
+      switch-prebuilt
     ];
 
     networking.firewall = {
@@ -103,6 +106,9 @@ in
       commands = [{
         command = "${rebuilder}/bin/rebuilder";
         options = [ "NOPASSWD" ];
+      } {
+        command = "${switch-prebuilt}/bin/switch-prebuilt";
+        options = [ "NOPASSWD" ];
       }];
     }];
     security.sudo.extraConfig = ''

ops/nixos/lib/switch-prebuilt.nix

@@ -0,0 +1,21 @@
+# SPDX-FileCopyrightText: 2020 Luke Granger-Brown <depot@lukegb.com>
+#
+# SPDX-License-Identifier: Apache-2.0
+
+{ depot, pkgs, ... }:
+pkgs.writeShellScriptBin "switch-prebuilt" ''
+  set -ue
+  if [[ $EUID -ne 0 ]]; then
+    exec sudo "$0" "$@"
+  fi
+
+
+  export AWS_ACCESS_KEY_ID="${depot.ops.secrets.nixCache.AWS_ACCESS_KEY_ID}"
+  export AWS_SECRET_ACCESS_KEY="${depot.ops.secrets.nixCache.AWS_SECRET_ACCESS_KEY}"
+  system="''${1}"
+
+  nix copy --from 's3://lukegb-nix-cache?endpoint=storage.googleapis.com' --no-check-sigs "$system"
+  diff "$system/etc/hostname" "/etc/hostname"
+  nix-env -p /nix/var/nix/profiles/system --set "$system"
+  "$system/bin/switch-to-configuration" switch
+''