add healthz endpoint

Author: supertassu

src/App.php

@@ -286,6 +286,11 @@ function () use ( $slim ) {
 					$page->setBaseUrl( 'https://sge-jobs.toolforge.org' );
 					$page( '/' );
 				} )->name( 'oge-status' );
+
+				$slim->get( 'healthz', function () use ( $slim ) {
+					$page = new Pages\Healthz();
+					$page();
+				} )->name( 'healthz' );
 			}
 		); // end group '/'
 

src/Pages/Healthz.php

@@ -0,0 +1,32 @@
+<?php
+/**
+ * This file is part of Toolforge Admin
+ * Copyright (C) 2016  Wikimedia Foundation and contributors
+ *
+ * This program is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation, either version 3 of the License, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+namespace Tools\Admin\Pages;
+
+use Wikimedia\Slimapp\Controller;
+
+/**
+ * Returns a 200 response.
+ */
+class Healthz extends Controller {
+	protected function handleGet() {
+		$this->contentType( 'text/plain' );
+		echo "OK";
+	}
+}