feat(ops/nixos): Add generic rebuild-system script r/1221

This adds a first crack at one idea for a generic, non-user-specific
rebuild-system script to ops.nixos.rebuild-system. The idea here is that
we enumerate all the nixos systems stored in the monorepo (similarly to
what we do for ci-builds right now) then search through them by hostname
to find the one matching the hostname of the current system, which is an
attempt at a more generic version of tazjin's rebuilder script which
does the same thing but with an explicit case block.

As a caveat, it feels like there's a slight possibility that this way of
finding systems is going to get slow to evaluate - on my system it feels
fine but if it grows out of hand it's probably feasible to just bake
this into the built script as a dynamically generated case statement.

Change-Id: I2e4c5401913b6f4d936ab48ba2f95f96e0e78eb4
Reviewed-on: https://cl.tvl.fyi/c/depot/+/894
Tested-by: BuildkiteCI
Reviewed-by: lukegb <lukegb@tvl.fyi>

1 files changed, 1 insertions, 5 deletions

diff --git a/ops/nixos/whitby/default.nix b/ops/nixos/whitby/default.nix
index 73066d6b9cad..b1055ddd2ee1 100644
--- a/ops/nixos/whitby/default.nix
+++ b/ops/nixos/whitby/default.nix
@@ -12,11 +12,7 @@ let
     mkdir -p $out/bin
     ln -s ${depot.ops.besadii}/bin/besadii $out/bin/post-command
   '';
-
-  systemForConfig = configuration: (depot.third_party.nixos {
-    inherit configuration;
-  }).system;
-in systemForConfig {
+in {
   inherit depot;
   imports = [
     "${depot.depotPath}/ops/nixos/depot.nix"