MDL-83753 cachestore_redis: Allow for configurable connection timeout…

… setting

cache/stores/redis/lib.php

@@ -65,9 +65,6 @@ class cachestore_redis extends store implements
      */
     const TTL_EXPIRE_BATCH = 10000;
 
-    /** @var int The number of seconds to wait for a connection or response from the Redis server. */
-    const CONNECTION_TIMEOUT = 10;
-
     /**
      * Name of this store.
      *
@@ -133,6 +130,13 @@ class cachestore_redis extends store implements
     /** @var ?array Array of current locks, or null if we haven't registered shutdown function */
     protected $currentlocks = null;
 
+    /**
+     * The number of seconds to wait for a connection or response from the Redis server.
+     *
+     * @var int
+     */
+    protected $connectiontimeout = 3;
+
     /**
      * Determines if the requirements for this type of store are met.
      *
@@ -203,6 +207,9 @@ public function __construct(
         if (array_key_exists('locktimeout', $configuration)) {
             $this->locktimeout = (int)$configuration['locktimeout'];
         }
+        if ($connectiontimeout = get_config('cachestore_redis', 'connectiontimeout')) {
+            $this->connectiontimeout = $connectiontimeout;
+        }
         $this->redis = $this->new_redis($configuration);
     }