From 1ddc5d2b1162b6b6815820243a15396a338b973c Mon Sep 17 00:00:00 2001
From: Astro <astro@spaceboyz.net>
Date: Wed, 8 Sep 2021 22:48:13 +0200
Subject: [PATCH] flake.nix: add -nixos-rebuild-local

---
 README.md |  7 +++++++
 flake.nix | 13 ++++++++++++-
 2 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/README.md b/README.md
index 688e0f4b..2590466f 100644
--- a/README.md
+++ b/README.md
@@ -66,6 +66,13 @@ for example: `nix run c3d2#glotzbert-nixos-rebuild switch`. Use `nix flake show
 to show what is available. Note that the deploy scripts only work if
 the target machines already has flakes enabled.
 
+Now that there is a `-local` variant that builds the system profile on
+your machine (possibly reusing dependencies that were built for other
+hosts), flakification of an existing NixOS host can be done using `nix
+run c3d2#glotzbert-nixos-rebuild-local switch`
+
+The must be an existing `nixosConfiguration.${host}` in `flake.nix`.
+
 ### Remote deployment from non-NixOS
 
 A shell script that copies the current working tree, and runs
diff --git a/flake.nix b/flake.nix
index 6d404b18..f1516dce 100644
--- a/flake.nix
+++ b/flake.nix
@@ -70,7 +70,7 @@
             # remote machine and bulding and switching there.
             # Can be run with nix run c3d2#deploy-…
             { name
-            , host ? "${name}.hq.c3d2.de"
+            , host
             # remote builders to pass
             , builders ? null
             }:
@@ -146,6 +146,17 @@
           } // nixpkgs.lib.optionalAttrs (hostRegistry.hosts.${name} ? builders) {
             inherit (hostRegistry.hosts.${name}) builders;
           });
+
+          "${name}-nixos-rebuild-local" =
+            let
+              host = getHostAddr name;
+              target = ''root@"${host}"'';
+              profile = self.nixosConfigurations.${name}.config.system.build.toplevel;
+            in pkgs.writeScriptBin "${name}-nixos-rebuild" ''
+              #!${pkgs.runtimeShell} -e
+              nix-copy-closure --to ${target} ${profile}
+              exec ssh -t ${target} "${profile}/bin/switch-to-configuration $@"
+            '';
         }) {} (builtins.attrNames flakifiedHosts)
       );