MDL-83753 redis: Set connection and read timeouts to configurable value

config-dist.php

@@ -370,6 +370,7 @@
 //      $CFG->session_redis_lock_expire = 7200;              // Optional, defaults to session timeout.
 //      $CFG->session_redis_lock_retry = 100;                // Optional wait between lock attempts in ms, default is 100.
 //                                                           // After 5 seconds it will throttle down to once per second.
+//      $CFG->session_redis_connection_timeout = 3;          // Optional wait for connection or response from Redis server.
 //
 //      Use the igbinary serializer instead of the php default one. Note that phpredis must be compiled with
 //      igbinary support to make the setting to work. Also, if you change the serializer you have to flush the database!

lib/classes/session/redis.php

@@ -106,16 +106,16 @@ class redis extends handler implements SessionHandlerInterface {
     protected bool $clustermode = false;
 
     /** @var int Maximum number of retries for cache store operations. */
-    const MAX_RETRIES = 5;
+    const MAX_RETRIES = 3;
 
     /** @var int $firstaccesstimeout The initial timeout (seconds) for the first browser access without login. */
     protected int $firstaccesstimeout = 180;
 
     /** @var clock A clock instance */
     protected clock $clock;
 
-    /** @var int The number of seconds to wait for a connection or response from the Redis server. */
-    const CONNECTION_TIMEOUT = 10;
+    /** @var int $connectiontimeout The number of seconds to wait for a connection or response from the Redis server. */
+    protected int $connectiontimeout = 3;
 
     /**
      * Create new instance of handler.
@@ -204,6 +204,10 @@ public function __construct() {
             $this->compressor = $CFG->session_redis_compressor;
         }
 
+        if (isset($CFG->session_redis_connection_timeout)) {
+            $this->connectiontimeout = (int)$CFG->session_redis_connection_timeout;
+        }
+
         $this->clock = di::get(clock::class);
     }
 
@@ -293,8 +297,8 @@ public function init(): bool {
                         $this->connection = new \RedisCluster(
                             name: null,
                             seeds: $trimmedservers,
-                            timeout: self::CONNECTION_TIMEOUT, // Timeout.
-                            read_timeout: self::CONNECTION_TIMEOUT, // Read timeout.
+                            timeout: $this->connectiontimeout, // Timeout.
+                            read_timeout: $this->connectiontimeout, // Read timeout.
                             persistent: true,
                             auth: $this->auth,
                             context: !empty($opts) ? $opts : null,
@@ -303,8 +307,8 @@ public function init(): bool {
                         $this->connection = new \RedisCluster(
                             null,
                             $trimmedservers,
-                            self::CONNECTION_TIMEOUT,
-                            self::CONNECTION_TIMEOUT,
+                            $this->connectiontimeout,
+                            $this->connectiontimeout,
                             true,
                             $this->auth,
                             !empty($opts) ? $opts : null
@@ -318,19 +322,19 @@ public function init(): bool {
                         $this->connection->connect(
                             host: $server,
                             port: $port,
-                            timeout: self::CONNECTION_TIMEOUT, // Timeout.
+                            timeout: $this->connectiontimeout, // Timeout.
                             retry_interval: $delay,
-                            read_timeout: self::CONNECTION_TIMEOUT, // Read timeout.
+                            read_timeout: $this->connectiontimeout, // Read timeout.
                             context: $opts,
                         );
                     } else {
                         $this->connection->connect(
                             $server,
                             $port,
-                            self::CONNECTION_TIMEOUT,
+                            $this->connectiontimeout,
                             null,
                             $delay,
-                            self::CONNECTION_TIMEOUT,
+                            $this->connectiontimeout,
                             $opts
                         );
                     }