Better cache file naming

nix/cache.nix

@@ -0,0 +1,41 @@
+{
+	writeShellApplication,
+	active,
+	distroFile,
+
+	curl,
+	minio-client,
+	packer,
+
+	...
+}:
+
+let
+	inherit (builtins) concatStringsSep map;
+in writeShellApplication {
+	name = "cache-isos";
+	runtimeInputs = [
+		curl
+		minio-client
+		packer
+	];
+	text = (concatStringsSep "\n" (
+		map (d: ''
+			url=$(echo var.iso.url | packer console -var-file="${distroFile d}" -config-type=hcl2 sources/)
+			sha=$(echo var.iso.checksum | packer console -var-file="${distroFile d}" -config-type=hcl2 sources/)
+			if [ ! -e "cache/$sha.iso" ]; then
+				curl --retry 3 --retry-all-errors -o "cache/$sha.iso" "$url"
+			else
+				echo "Skipping ${d.distro} - cache/$sha.iso"
+			fi
+		'') active
+	)) + ''
+		ls -lh cache/
+
+		mc alias set storage "$STORAGE_URL" root "$MINIO_SECRET"
+
+		for f in cache/*; do
+			mc put "$f" "storage/isos/$f"
+		done
+	'';
+}