Remove 'sentinel_master_cache' feature and restore verification as optional 'sentinel_master_verify' feature.

Author: colinmollenhour

Cm/Cache/Backend/Redis.php

@@ -59,8 +59,6 @@ class Cm_Cache_Backend_Redis extends Zend_Cache_Backend implements Zend_Cache_Ba
     const LUA_CLEAN_SH1 = '42ab2fe548aee5ff540123687a2c39a38b54e4a2';
     const LUA_GC_SH1 = 'c00416b970f1aa6363b44965d4cf60ee99a6f065';
 
-    const SENTINEL_CACHE_KEY = 'cm_cache_redis:sentinel';
-
     /** @var Credis_Client */
     protected $_redis;
 
@@ -159,21 +157,8 @@ public function __construct($options = array())
 
         $this->_clientOptions = $this->getClientOptions($options);
 
-        // Try to load selected master from cache
-        if ($sentinelMaster && ! empty($options['sentinel_master_cache']) && function_exists('apcu_fetch')) {
-            $cacheData = apcu_fetch(self::SENTINEL_CACHE_KEY);
-            if ($cacheData) {
-                $this->_redis = new Credis_Client($cacheData['master']['host'], $cacheData['master']['port'], $timeout, $persistent);
-                $this->_applyClientOptions($this->_redis);
-                if ( ! empty($cacheData['slave'])) {
-                    $this->_slave = new Credis_Client($cacheData['slave']['host'], $cacheData['slave']['port'], $timeout, $persistent);
-                    $this->_applyClientOptions($this->_slave, TRUE);
-                }
-            }
-        }
-
         // If 'sentinel_master' is specified then server is actually sentinel and master address should be fetched from server.
-        if ($sentinelMaster && ! $this->_redis) {
+        if ($sentinelMaster) {
             $sentinelClientOptions = isset($options['sentinel']) && is_array($options['sentinel']) 
                                      ? $this->getClientOptions($options['sentinel'] + $options)
                                      : $this->_clientOptions;
@@ -198,6 +183,21 @@ public function __construct($options = array())
                         ->setClientPersistent($this->_clientOptions->persistent);
                     $redisMaster = $sentinel->getMasterClient($sentinelMaster);
                     $this->_applyClientOptions($redisMaster);
+
+                    // Verify connected server is actually master as per Sentinel client spec
+                    if ( ! empty($options['sentinel_master_verify'])) {
+                        $roleData = $redisMaster->role();
+                        if ( ! $roleData || $roleData[0] != 'master') {
+                            usleep(100000); // Sleep 100ms and try again
+                            $redisMaster = $sentinel->getMasterClient($sentinelMaster);
+                            $this->_applyClientOptions($redisMaster);
+                            $roleData = $redisMaster->role();
+                            if ( ! $roleData || $roleData[0] != 'master') {
+                                Zend_Cache::throwException('Unable to determine master redis server.');
+                            }
+                        }
+                    }
+
                     $this->_redis = $redisMaster;
                     break;
                 } catch (Exception $e) {
@@ -229,20 +229,10 @@ public function __construct($options = array())
                 }
             }
             unset($sentinel);
-
-            // Cache data in memory to skip sentinel
-            if ( ! empty($options['sentinel_master_cache']) && function_exists('apcu_fetch')) {
-                $cacheData = ['master' => ['host' => $this->_redis->getHost(), 'port' => $this->_redis->getPort()]];
-                if ($this->_slave) {
-                    $cacheData['slave'] = ['host' => $this->_slave->getHost(), 'port' => $this->_slave->getPort()];
-                }
-                // Save master/slave data from 1 to 15 seconds
-                apcu_store(self::SENTINEL_CACHE_KEY, $cacheData, min(15,max(1,(int)$options['sentinel_master_cache'])));
-            }
         }
 
         // Direct connection to single Redis server
-        else if ( ! $sentinelMaster ) {
+        else {
             $this->_redis = new Credis_Client($options['server'], $port, $this->_clientOptions->timeout, $this->_clientOptions->persistent);
             $this->_applyClientOptions($this->_redis);
 

README.md

@@ -92,7 +92,7 @@ Example configuration:
             <server>tcp://10.0.0.1:26379,tcp://10.0.0.2:26379,tcp://10.0.0.3:26379</server>
             <timeout>0.5</timeout>
             <sentinel_master>mymaster</sentinel_master>
-            <sentinel_master_cache>1</sentinel_master_cache>
+            <sentinel_master_verify>1</sentinel_master_verify>
             <load_from_slaves>1</load_from_slaves>
           </backend_options>
         </cache>