libkookie: add build-on-remote utility

infra/libkookie/build-on-remote

@@ -0,0 +1,23 @@
+#!/bin/sh
+
+HOST=$(hostname)
+DIR=$(realpath $(dirname $0))
+OUT=$(mktemp -du)
+ROOT="$DIR/roots/$HOST.nix"
+
+# By default build on hyperion
+if [ -z "$REMOTE" ]
+then
+    REMOTE="hyperion"
+fi
+
+drvs="$(nix-instantiate -A system '<nixpkgs/nixos>' \
+            -I nixos-config="$ROOT" \
+            -I "nixpkgs=$DIR/nixpkgs" \
+            -I "nixpkgs-overlays=$DIR/overlays" \
+            -I "home-manager=$DIR/home-manager" \
+            -I "modules=$DIR/modules" \
+            -I "configuration=$DIR/configuration")"
+
+nix-copy-closure -s --to $REMOTE $drvs
+nix-copy-closure --from $REMOTE $(ssh $REMOTE nix-build $drvs)