Refactor deploy script

utils/deploy

@@ -0,0 +1,14 @@
+#!/usr/bin/env bash
+
+set -e
+set -o pipefail
+
+if [ -z "$1" ]
+then
+	echo "usage: deploy <hostname>"
+	exit 1
+fi
+
+git push
+
+gen-config $1 | ssh "${host}".dadada.li 'sudo cat - > /etc/nixos/configuration.nix && (nixos-rebuild test && nixos-rebuild switch) || (nixos-rebuild switch --rollback && exit 1)'

utils/gen-config

@@ -0,0 +1,37 @@
+#!/usr/bin/env bash
+
+function hash {
+	archive="$(mktemp /tmp/nix-config.XXX.tar.gz)"
+	git archive "$1" | gzip > "$archive"
+	nix-prefetch-url --unpack --type sha256 "file:$archive" 2>/dev/null
+	rm "$archive"
+}
+
+if [ -z "$1" ]
+then
+	echo "usage: deploy <hostname>"
+	exit 1
+fi
+
+host="${1}"
+rev="$(git rev-parse HEAD)"
+sha256=$(hash "$rev")
+
+cat <<EOF
+{ config, pkgs, ... }:
+let
+  host = "$host";
+  rev = "$rev";
+  sha256 = "$sha256";
+  dadada = import (builtins.fetchTarball {
+    url = "https://github.com/dadada/nix-config/archive/\${rev}.tar.gz";
+    sha256 = sha256;
+  }) { inherit pkgs; };
+in
+{
+  imports = [
+    ./hardware-configuration.nix
+    dadada.hosts."\${host}"
+  ];
+}
+EOF