krops: add writePopulate

pkgs/krops/default.nix

@@ -8,34 +8,42 @@ let
   };
 in
 
-{ nix, openssh, populate, writeDash, writeJSON }: {
+{ nix, openssh, populate, writeDash, writeJSON }: let
+
+  populate' = name: { source, target }:
+    writeDash "${name}-populate" ''
+      set -efu
+      source=${writeJSON "${name}-source.json" source}
+      target=${target.user}@${target.host}:${target.port}${target.path}
+      exec ${populate}/bin/populate "$target" < "$source"
+    '';
+
+in {
 
   writeDeploy = name: { source, target }: let
     target' = lib.mkTarget target;
   in
     writeDash name ''
       set -efu
-
-      ${populate}/bin/populate \
-          ${target'.user}@${target'.host}:${target'.port}${target'.path} \
-        < ${writeJSON "${name}-source.json" source}
-
+      ${populate' name { inherit source; target = target'; }}
       ${openssh}/bin/ssh \
           ${target'.user}@${target'.host} -p ${target'.port} \
           nixos-rebuild switch -I ${target'.path}
     '';
 
+  writePopulate = name: { source, target }:
+    populate' name {
+      inherit source;
+      target = lib.mkTarget target;
+    };
+
   writeTest = name: { source, target }: let
     target' = lib.mkTarget target;
   in
     assert lib.isLocalTarget target';
     writeDash name ''
       set -efu
-
-      ${populate}/bin/populate --force \
-          ${target'.path} \
-        < ${writeJSON "${name}-source.json" source}
-
+      ${populate' name { inherit source; target = target'; }}
       ${nix}/bin/nix-build \
           -A config.system.build.toplevel \
           -I ${target'.path} \