“Error establishing a database connection” WordPress and Google App Engine

I have been trying to follow this tutorial on launching a wordpress site using google app engine. I have the site deployed and I created a SQL instance on the site project, but the site apparently doesn’t see the instance. In the tutorial it says to input this command into the MySQL Command Line Client:

{PATH_TO_MYSQL_BIN}/mysql --host=INSTANCE_IP --user=root --password
create database wordpress_db;
exit;

And whenever I do I get syntax errors. I don’t know what it means by {PATH_TO_MYSQL_BIN}/mysql is that the path to my project folder? Or do I even need to use this command?

The SQL instance I set up on the Google Cloud Platform is a first generation. Shouldn’t it automatically link the database to the project? And if so, why am I getting an error message?

My SQL instance name is wordpress-a and my project id is blendertrainer.

Here is my App.yaml:

application: blendertrainer
version: firstlaunching
runtime: php55
api_version: 1

handlers:
- url: /(.*.(htm|html|css|js))$
  static_files: wordpress/1
  upload: wordpress/.*.(htm|html|css|js)$
  application_readable: true

- url: /wp-content/(.*.(ico|jpg|jpeg|png|gif|woff|ttf|otf|eot|svg))$
  static_files: wordpress/wp-content/1
  upload: wordpress/wp-content/.*.(ico|jpg|jpeg|png|gif|woff|ttf|otf|eot|svg)$
  application_readable: true

- url: /(.*.(ico|jpg|jpeg|png|gif|woff|ttf|otf|eot|svg))$
  static_files: wordpress/1
  upload: wordpress/.*.(ico|jpg|jpeg|png|gif|woff|ttf|otf|eot|svg)$
  application_readable: true

- url: /wp-includes/images/media/(.*.(ico|jpg|jpeg|png|gif|woff|ttf|otf|eot|svg))$
  static_files: wordpress/wp-includes/images/media/1
  upload: wordpress/wp-includes/images/media/.*.(ico|jpg|jpeg|png|gif|woff|ttf|otf|eot|svg)$
  application_readable: true

- url: /wp-admin/(.+)
  script: wordpress/wp-admin/1
  secure: always

- url: /wp-admin/
  script: wordpress/wp-admin/index.php
  secure: always

- url: /wp-login.php
  script: wordpress/wp-login.php
  secure: always

- url: /wp-cron.php
  script: wordpress/wp-cron.php
  login: admin

- url: /xmlrpc.php
  script: wordpress/xmlrpc.php

- url: /wp-(.+).php
  script: wordpress/wp-1.php

- url: /(.+)?/?
  script: wordpress/index.php

skip_files:
- ^(.*/)?.zip$
- ^(.*/)?.bat$
- ^(.*/)?.sh$
- ^(.*/)?.md$

Here is my wp_config:

<?php
    /**
     * The base configurations of the WordPress.
     *
     * This file has the following configurations: MySQL settings, Table Prefix,
     * Secret Keys, WordPress Language, and ABSPATH. You can find more information
     * by visiting {@link http://codex.wordpress.org/Editing_wp-config.php Editing
     * wp-config.php} Codex page. You can get the MySQL settings from your web host.
     *
     * This file is used by the wp-config.php creation script during the
     * installation. You don't have to use the web site, you can just copy this file
     * to "wp-config.php" and fill in the values.
     *
     * @package WordPress
     */

    // Required for batcache use
    define('WP_CACHE', true);

    // ** MySQL settings - You can get this info from your web host ** //
    /** The name of the database for WordPress */
    define('DB_NAME', 'wordpress_db');

    if (isset($_SERVER['SERVER_SOFTWARE']) && strpos($_SERVER['SERVER_SOFTWARE'],'Google App Engine') !== false) {
        /** Live environment Cloud SQL login and SITE_URL info */
        /** Note that from App Engine, the password is not required, so leave it blank here */
        define('DB_HOST', ':/cloudsql/blendertrainer:wordpress-a');
        define('DB_USER', 'root');
        define('DB_PASSWORD', '');
    } else {
        /** Local environment MySQL login info */
        define('DB_HOST', '127.0.0.1');
        define('DB_USER', 'root');
        define('DB_PASSWORD', '*********');
    }

    // Determine HTTP or HTTPS, then set WP_SITEURL and WP_HOME
    if (!empty($_SERVER['HTTPS']) && $_SERVER['HTTPS'] !== 'off' || $_SERVER['SERVER_PORT'] == 443)
    {
        $protocol_to_use = 'https://';
    } else {
        $protocol_to_use = 'http://';
    }
    define( 'WP_SITEURL', $protocol_to_use . $_SERVER['HTTP_HOST']);
    define( 'WP_HOME', $protocol_to_use . $_SERVER['HTTP_HOST']);

    /** Database Charset to use in creating database tables. */
    define('DB_CHARSET', 'utf8');

    /** The Database Collate type. Don't change this if in doubt. */
    define('DB_COLLATE', '');

    /**#@+
     * Authentication Unique Keys and Salts.
     *
     * Change these to different unique phrases!
     * You can generate these using the {@link https://api.wordpress.org/secret-key/1.1/salt/ WordPress.org secret-key service}
     * You can change these at any point in time to invalidate all existing cookies. This will force all users to have to log in again.
     *
     * @since 2.6.0
     */
    define('AUTH_KEY',         'put your unique phrase here');
    define('SECURE_AUTH_KEY',  'put your unique phrase here');
    define('LOGGED_IN_KEY',    'put your unique phrase here');
    define('NONCE_KEY',        'put your unique phrase here');
    define('AUTH_SALT',        'put your unique phrase here');
    define('SECURE_AUTH_SALT', 'put your unique phrase here');
    define('LOGGED_IN_SALT',   'put your unique phrase here');
    define('NONCE_SALT',       'put your unique phrase here');

    /**#@-*/

    /**
     * WordPress Database Table prefix.
     *
     * You can have multiple installations in one database if you give each a unique
     * prefix. Only numbers, letters, and underscores please!
     */
    $table_prefix  = 'wp_';

    /**
     * WordPress Localized Language, defaults to English.
     *
     * Change this to localize WordPress. A corresponding MO file for the chosen
     * language must be installed to wp-content/languages. For example, install
     * de_DE.mo to wp-content/languages and set WPLANG to 'de_DE' to enable German
     * language support.
     */
    define('WPLANG', '');

    /**
     * For developers: WordPress debugging mode.
     *
     * Change this to true to enable the display of notices during development.
     * It is strongly recommended that plugin and theme developers use WP_DEBUG
     * in their development environments.
     */
    define('WP_DEBUG', false);

    /**
     * Disable default wp-cron in favor of a real cron job
     */
    define('DISABLE_WP_CRON', true);

    // configures batcache
    $batcache = [
      'seconds'=>0,
      'max_age'=>30*60, // 30 minutes
      'debug'=>false
    ];
    /* That's all, stop editing! Happy blogging. */

    /** Absolute path to the WordPress directory. */
    if ( !defined('ABSPATH') )
        define('ABSPATH', dirname(__FILE__) . '/wordpress/');

    /** Sets up WordPress vars and included files. */
    require_once(ABSPATH . 'wp-settings.php');