ansible-inventories/gentner#158 New Redis settings, optional at this time

templates/d8_settings.php

@@ -60,7 +60,7 @@ $config_directories['{{ directory }}'] = 'sites/{{ item.shortname|default("defau
 {% endfor %}
 
 // Set redis configuration.
-if (file_exists('modules/contrib/redis/redis.info.yml')) {
+if (file_exists('modules/contrib/redis/redis.info.yml') && extension_loaded('redis')) {
   // Set Redis as the default backend for any cache bin not otherwise specified.
   $settings['redis.connection']['interface'] = 'PhpRedis';
   $settings['cache']['default'] = 'cache.backend.redis';
@@ -93,7 +93,7 @@ if (file_exists('modules/contrib/redis/redis.info.yml')) {
       ],
       'cache.backend.redis' => [
         'class' => 'Drupal\redis\Cache\CacheBackendFactory',
-        'arguments' => ['@redis.factory', '@cache_tags_provider.container'],
+        'arguments' => ['@redis.factory', '@cache_tags_provider.container'{% if item.redis_serialize|default(false) %}, '@serialization.phpserialize'{% endif %}],
       ],
       'cache.container' => [
         'class' => '\Drupal\redis\Cache\PhpRedis',
@@ -104,6 +104,11 @@ if (file_exists('modules/contrib/redis/redis.info.yml')) {
         'class' => 'Drupal\redis\Cache\RedisCacheTagsChecksum',
         'arguments' => ['@redis.factory'],
       ],
+{% if item.redis_serialize|default(false) %}
+      'serialization.phpserialize' => [
+        'class' => 'Drupal\Component\Serialization\PhpSerialize',
+      ],
+{% endif %}
     ],
   ];
 
@@ -114,6 +119,18 @@ if (file_exists('modules/contrib/redis/redis.info.yml')) {
 {% else %}
   $settings['cache_prefix'] = '{{ item.shortname|default("default") }}_';
 {% endif %}
+
+{% if drupal.version_8_1|default(false) %}
+  // Drupal 8.1 has a bug where certain special caches that should use the
+  // APCu cache if available will not do so if a non-SQL default is specified.
+  // The following lines explicitly force those cache bins to use the correct
+  // cache backend. This block may be removed in Drupal 8.2.
+  // @see https://www.drupal.org/node/2753989
+  $settings['cache']['bins']['bootstrap'] = 'cache.backend.chainedfast';
+  $settings['cache']['bins']['discovery'] = 'cache.backend.chainedfast';
+  $settings['cache']['bins']['config'] = 'cache.backend.chainedfast';
+  $settings['cache']['bins']['static'] = 'cache.backend.memory';
+{% endif %}
 }
 
 if (file_exists(__DIR__ . '/settings.local.php')) {