diff --git a/inc/cache.php b/inc/cache.php
index 33e03746..6e81039a 100644
--- a/inc/cache.php
+++ b/inc/cache.php
@@ -12,10 +12,10 @@ defined('TINYBOARD') or exit;
 class Cache {
 	private static function buildCache(): CacheDriver {
 		global $config;
-		// Determine if Redis is configured via environment variables
-		getenv('VICHAN_CACHE_ENGINE') && $config['cache']['enabled'] = getenv('VICHAN_CACHE_ENGINE');
+		// Determine if the cache engine is configured via environment variables.
+		$engine = \getenv('VICHAN_CACHE_ENGINE') ?: $config['cache']['enabled'];
 
-		switch ($config['cache']['enabled']) {
+		switch ($engine) {
 			case 'memcached':
 				return new MemcachedCacheDriver(
 					$config['cache']['prefix'],
@@ -31,7 +31,7 @@ class Cache {
 				$port = getenv('VICHAN_CACHE_PORT') ?: $port;
 				$password = getenv('VICHAN_CACHE_PASSWORD') ?: $password;
 				$database = getenv('VICHAN_CACHE_DATABASE') ?: $database;
-				
+
 				return new RedisCacheDriver(
 					$config['cache']['prefix'],
 					$host,
diff --git a/inc/template.php b/inc/template.php
index 47b7bc0f..11d9ea10 100644
--- a/inc/template.php
+++ b/inc/template.php
@@ -142,7 +142,8 @@ class Tinyboard extends Twig\Extension\AbstractExtension
 			new Twig\TwigFunction('ratio', 'twig_ratio_function'),
 			new Twig\TwigFunction('secure_link_confirm', 'twig_secure_link_confirm'),
 			new Twig\TwigFunction('secure_link', 'twig_secure_link'),
-			new Twig\TwigFunction('link_for', 'link_for')
+			new Twig\TwigFunction('link_for', 'link_for'),
+			new Twig\TwigFunction('check_container', 'twig_check_container')
 		);
 	}
 
@@ -226,18 +227,18 @@ function twig_secure_link($href) {
 	return $href . '/' . make_secure_link_token($href);
 }
 
-// /*
-//  * ====================
-//  *  Container Detection
-//  * ===================
-//  */
+/*
+ * ====================
+ *  Container Detection
+ * ===================
+ */
 
 function twig_check_container() {
-	global $config;
-	$isDocker = is_file("/.dockerenv") || is_file("/run/.containerenv");
-	$isKubernetes = is_file("/var/run/secrets/kubernetes.io/serviceaccount/namespace");
-	$config['is_container'] = $isDocker || $isKubernetes ? true : false;
-	$config['is_docker'] = $isDocker;
-	$config['is_kubernetes'] = $isKubernetes;
-	return $config['is_container'];
-}
\ No newline at end of file
+	static $is_container = null;
+	if ($is_container === null) {
+		$is_docker = \is_file("/.dockerenv") || \is_file("/run/.containerenv");
+		$is_kubernetes = \is_file("/var/run/secrets/kubernetes.io/serviceaccount/namespace");
+		$is_container = $is_docker || $is_kubernetes;
+	}
+	return $is_container;
+}