使用redis模擬memcach多伺服器承載

fiona8953發表於2014-08-27
Redis伺服器


如題分享一老外實現思路，拋開redis自身配置主從外模擬memcache中hash多伺服器承載

原文

作者思路不錯，大家可以借鑑

點選(此處)摺疊或開啟

  1. php
  2. /**
  3. * Redisent, a Redis interface for the modest
  4. * @author Justin Poliey
  5. * @copyright 2009 Justin Poliey
  6. * @license php The MIT License
  7. * @package Redisent
  8. */

  10. require \'redisent.php\';

  12. /**
  13. * A generalized Redisent interface for a cluster of Redis servers
  14. */
  15. class RedisentCluster {

  17.         /**
  18.          * Collection of Redisent objects attached to Redis servers
  19.          * @var array
  20.          * @access private
  21.          */
  22.         private $redisents;

  24.         /**
  25.          * Aliases of Redisent objects attached to Redis servers, used to route commands to specific servers
  26.          * @see RedisentCluster::to
  27.          * @var array
  28.          * @access private
  29.          */
  30.         private $aliases;

  32.         /**
  33.          * Hash ring of Redis server nodes
  34.          * @var array
  35.          * @access private
  36.          */
  37.         private $ring;

  39.         /**
  40.          * Individual nodes of pointers to Redis servers on the hash ring
  41.          * @var array
  42.          * @access private
  43.          */
  44.         private $nodes;

  46.         /**
  47.          * Number of replicas of each node to make around the hash ring
  48.          * @var integer
  49.          * @access private
  50.          */
  51.         private $replicas = 128;

  53.         /*** 特殊方法預設到特定連線
  54.          * The commands that are not subject to hashing
  55.          * @var array
  56.          * @access private
  57.          */
  58.         private $dont_hash = array(
  59.                 \'RANDOMKEY\', \'DBSIZE\',
  60.                 \'SELECT\', \'MOVE\', \'FLUSHDB\', \'FLUSHALL\',
  61.                 \'SAVE\', \'BGSAVE\', \'LASTSAVE\', \'SHUTDOWN\',
  62.                 \'INFO\', \'MONITOR\', \'SLAVEOF\'
  63.         );

  65.         /**
  66.          * Creates a Redisent interface to a cluster of Redis servers
  67.          * @param array $servers The Redis servers in the cluster. Each server should be in the format array(\'host\' => hostname, \'port\' => port)
  68.          */
  69.         function __construct($servers) {
  70.                 $this->ring = array();
  71.                 $this->aliases = array();
  72.                 foreach ($servers as $alias => $server) {
  73.                         $this->redisents[] = new Redisent($server[\'host\'], $server[\'port\']);
  74.                         if (is_string($alias)) {
  75.                                 $this->aliases[$alias] = $this->redisents[count($this->redisents)-1];
  76.                         }
  77.                         for ($replica = 1; $replica <= $this->replicas; $replica++) {
  78.                                 $this->ring[crc32($server[\'host\'].\':\'.$server[\'port\'].\'-\'.$replica)] = $this->redisents[count($this->redisents)-1];
  79.                         }
  80.                 }
  81.                 ksort($this->ring, SORT_NUMERIC);
  82.                 $this->nodes = array_keys($this->ring);
  83.         }

  85.         /**
  86.          * Routes a command to a specific Redis server aliased by {$alias}.
  87.          * @param string $alias The alias of the Redis server
  88.          * @return Redisent The Redisent object attached to the Redis server
  89.          */
  90.         function to($alias) {
  91.                 if (isset($this->aliases[$alias])) {
  92.                         return $this->aliases[$alias];
  93.                 }
  94.                 else {
  95.                         throw new Exception(\"That Redisent alias does not exist\");
  96.                 }
  97.         }

  99.         /* Execute a Redis command on the cluster */
  100.         function __call($name, $args) {

  102.                 /* Pick a server node to send the command to */
  103.                 $name = strtoupper($name);
  104.                 if (!in_array($name, $this->dont_hash)) {
  105.                         $node = $this->nextNode(crc32($args[0]));
  106.                         $redisent = $this->ring[$node];
  107.             }
  108.             else {
  109.                         $redisent = $this->redisents[0];
  110.             }

  112.                 /* Execute the command on the server */
  113.             return call_user_func_array(array($redisent, $name), $args);
  114.         }

  116.         /*** 2分法查詢
  117.          * Routes to the proper server node
  118.          * @param integer $needle The hash value of the Redis command
  119.          * @return Redisent The Redisent object associated with the hash
  120.          */
  121.         private function nextNode($needle) {
  122.                 $haystack = $this->nodes;
  123.                 while (count($haystack) > 2) {
  124.                         $try = floor(count($haystack) / 2);
  125.                         if ($haystack[$try] == $needle) {
  126.                                 return $needle;
  127.                         }
  128.                         if ($needle < $haystack[$try]) {
  129.                                 $haystack = array_slice($haystack, 0, $try + 1);
  130.                         }
  131.                         if ($needle > $haystack[$try]) {
  132.                                 $haystack = array_slice($haystack, $try + 1);
  133.                         }
  134.                 }
  135.                 return $haystack[count($haystack)-1];
  136.         }

  138. }


來自 “ ITPUB部落格 ” ，連結：http://blog.itpub.net/26477398/viewspace-1258943/，如需轉載，請註明出處，否則將追究法律責任。

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