feat(scripts/cache-node): support non-NixOS systems

Signed-off-by: Ryan Lahfa <ryan@dgnum.eu>

scripts/cache-node.sh

@@ -3,7 +3,25 @@ set -o nounset
 set -o pipefail
 shopt -s lastpipe
 
-drv=$(colmena eval --instantiate -E "{ nodes, ... }: nodes.${BUILD_NODE}.config.system.build.toplevel")
+system_type="$(colmena eval -E "{ nodes, ... }: nodes.${BUILD_NODE}.config.deployment.systemType")"
+# Get rid of surrounding quotes.
+system_type="${system_type%\"}"
+system_type="${system_type#\"}"
+
+case "$system_type" in
+  nixos)
+    toplevel_path="config.system.build.toplevel"
+    ;;
+  zyxel-nwa50ax)
+    toplevel_path="config.system.outputs.zyxel-nwa-fit"
+    ;;
+  *)
+    echo "Unsupported system type '$system_type' for caching; add an entry in 'scripts/cache-node.sh'"
+    exit 1
+    ;;
+esac
+
+drv=$(colmena eval --instantiate -E "{ nodes, ... }: nodes.${BUILD_NODE}.${toplevel_path}")
 
 # Build the derivation and send it to the great beyond
 nix-store --query --requisites --force-realise --include-outputs "$drv" | grep -v '.*\.drv' >paths.txt