http_host error with wp-cli

wp-config-sample.php

@@ -29,6 +29,7 @@ $table_prefix  = getenv('TABLE_PREFIX');
 
 define( 'WPLANG', '' );
 define( 'WP_CONTENT_DIR', dirname( __FILE__ ) . '/app' );
+// *********** $_SERVER['HTTP_HOST'] will cause warnings with wp-cli ************** //
 define( 'WP_CONTENT_URL', 'http://' . $_SERVER['HTTP_HOST'] . '/wp/app' );
 define( 'PLUGINDIR', dirname(__FILE__) . '/app/plugins' );