MDL-83753 cachestore_redis: Allow for configurable connection timeout

cache/stores/redis/addinstanceform.php

@@ -65,5 +65,10 @@ class cachestore_redis_addinstance_form extends cachestore_addinstance_form {
         $form->addHelpButton('compressor', 'usecompressor', 'cachestore_redis');
         $form->setDefault('compressor', cachestore_redis::COMPRESSOR_NONE);
         $form->setType('compressor', PARAM_INT);
+
+        $form->addElement('text', 'connectiontimeout', get_string('connectiontimeout', 'cachestore_redis'));
+        $form->addHelpButton('connectiontimeout', 'connectiontimeout', 'cachestore_redis');
+        $form->setDefault('connectiontimeout', cachestore_redis::CONNECTION_TIMEOUT);
+        $form->setType('connectiontimeout', PARAM_INT);
     }
 }

cache/stores/redis/lang/en/cachestore_redis.php

@@ -32,6 +32,8 @@ $string['clustermodeunavailable'] = 'Redis Cluster is currently unavailable. Ple
 $string['compressor_none'] = 'No compression.';
 $string['compressor_php_gzip'] = 'Use gzip compression.';
 $string['compressor_php_zstd'] = 'Use Zstandard compression.';
+$string['connectiontimeout'] = 'Connection timeout';
+$string['connectiontimeout_help'] = 'This sets the timeout when attempting to connect to the Redis server.';
 $string['encrypt_connection'] = 'Use TLS encryption.';
 $string['encrypt_connection_help'] = 'Use TLS to connect to Redis. Do not use \'tls://\' in the hostname for Redis, use this option instead.';
 $string['password'] = 'Password';

cache/stores/redis/lib.php

@@ -66,7 +66,7 @@ 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;
+    const CONNECTION_TIMEOUT = 3;
 
     /**
      * Name of this store.
@@ -117,6 +117,14 @@ class cachestore_redis extends store implements
      */
     protected $compressor = self::COMPRESSOR_NONE;
 
+
+    /**
+     * The number of seconds to wait for a connection or response from the Redis server.
+     *
+     * @var int
+     */
+    protected $connectiontimeout = self::CONNECTION_TIMEOUT;
+
     /**
      * Bytes read or written by last call to set()/get() or set_many()/get_many().
      *
@@ -197,6 +205,9 @@ class cachestore_redis extends store implements
         if (array_key_exists('compressor', $configuration)) {
             $this->compressor = (int)$configuration['compressor'];
         }
+        if (array_key_exists('connectiontimeout', $configuration)) {
+            $this->connectiontimeout = (int)$configuration['connectiontimeout'];
+        }
         if (array_key_exists('lockwait', $configuration)) {
             $this->lockwait = (int)$configuration['lockwait'];
         }
@@ -277,8 +288,8 @@ class cachestore_redis extends store implements
                     $redis = 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: $password,
                         context: !empty($opts) ? $opts : null,
@@ -287,8 +298,8 @@ class cachestore_redis extends store implements
                     $redis = new RedisCluster(
                         null,
                         $trimmedservers,
-                        self::CONNECTION_TIMEOUT,
-                        self::CONNECTION_TIMEOUT,
+                        $this->connectiontimeout,
+                        $this->connectiontimeout,
                         true, $password,
                         !empty($opts) ? $opts : null,
                     );
@@ -300,18 +311,18 @@ class cachestore_redis extends store implements
                     $redis->connect(
                         host: $server,
                         port: $port,
-                        timeout: self::CONNECTION_TIMEOUT, // Timeout.
+                        timeout: $this->connectiontimeout, // Timeout.
                         retry_interval: 100, // Retry interval.
-                        read_timeout: self::CONNECTION_TIMEOUT, // Read timeout.
+                        read_timeout: $this->connectiontimeout, // Read timeout.
                         context: $opts,
                     );
                 } else {
                     $redis->connect(
                         $server, $port,
-                        self::CONNECTION_TIMEOUT,
+                        $this->connectiontimeout,
                         null,
                         100,
-                        self::CONNECTION_TIMEOUT,
+                        $this->connectiontimeout,
                         $opts,
                     );
                 }
@@ -863,6 +874,7 @@ class cachestore_redis extends store implements
             'password' => $data->password,
             'serializer' => $data->serializer,
             'compressor' => $data->compressor,
+            'connectiontimeout' => $data->connectiontimeout,
             'encryption' => $data->encryption,
             'cafile' => $data->cafile,
             'clustermode' => $data->clustermode,
@@ -887,6 +899,9 @@ class cachestore_redis extends store implements
         if (!empty($config['compressor'])) {
             $data['compressor'] = $config['compressor'];
         }
+        if (!empty($config['connectiontimeout'])) {
+            $data['connectiontimeout'] = $config['connectiontimeout'];
+        }
         if (!empty($config['encryption'])) {
             $data['encryption'] = $config['encryption'];
         }