Varnish health check failing due to presence of id_prefix in env.php

Author: Nazar65

pub/health_check.php

@@ -43,7 +43,10 @@
 $cacheConfigs = $deploymentConfig->get(ConfigOptionsListConstants::KEY_CACHE_FRONTEND);
 if ($cacheConfigs) {
     foreach ($cacheConfigs as $cacheConfig) {
-        if (!isset($cacheConfig[ConfigOptionsListConstants::CONFIG_PATH_BACKEND]) ||
+        // allow config if only available "id_prefix"
+        if (count($cacheConfig) === 1 && isset($cacheConfig['id_prefix'])) {
+            continue;
+        } elseif (!isset($cacheConfig[ConfigOptionsListConstants::CONFIG_PATH_BACKEND]) ||
             !isset($cacheConfig[ConfigOptionsListConstants::CONFIG_PATH_BACKEND_OPTIONS])) {
             http_response_code(500);
             $logger->error("Cache configuration is invalid");