Trigger Varnish cache purge on deploy to WP Engine
<?php
add_action( 'init', function(){
// Replace '901bcc678021c0e12f1583085cafda1d' with a secret of your own.
if ( ! empty( $_GET['purge-cache'] ) && '901bcc678021c0e12f1583085cafda1d' === $_GET['purge-cache'] ) {
WpeCommon::purge_varnish_cache_all();
echo 'Cache purged';
exit;
}
});