krops writeTest: make trace optional

README.md

@@ -152,6 +152,10 @@ below `/var/src`, and executes `NIX_PATH=/var/src nix-build -A system '<nixpkgs/
 
 [see `writeDeploy`](#writeDeploy)
 
+### `trace` (optional, defaults to false)
+
+run nix-build with `--show-trace`
+
 ## writeCommand
 
 This can be used to run other commands than `nixos-rebuild` or pre/post build hooks.

pkgs/krops/default.nix

@@ -81,7 +81,8 @@ in
     backup ? false,
     force ? false,
     source,
-    target
+    target,
+    trace ? false
   }: let
     target' = lib.mkTarget target;
   in
@@ -94,7 +95,7 @@ in
           -A system \
           --keep-going \
           --no-out-link \
-          --show-trace \
+          ${lib.optionalString trace "--show-trace"} \
           '<nixpkgs/nixos>'
     '';
 }