This is a version of sfMemcached modified to allow multiple servers to be used. Servers are grouped in buckets for organization.

A bucket must be initialized before it is used.

Example:

sfAdvMemcachedCache::createInstance('function', array (
  'lifetime' => 60
  'servers' => 
  array (
    array (
      'host' => '72.29.86.195',
      'port' => 11211,
      'persistent' => true,
      'weight' => 2,
      'timeout' => 1,
      'retry_interval' => 1,
      'status' => 1,
    )
  )
));

Then the bucket can be used through a call to getInstnace(bucketName)

Ex:

sfAdvMemcacheCache::getInstance('function')->set('helloKey', 'world_data');

For ease of use, multiple buckets and servers can be defined and auto-intialized through a YAML file called memcached.yml that will sit in the /config folder of your application.

Example configuration:

default:
  servers:
    default:
      host: localhost
      port: 11211
      timeout: 1
      weight: 1
      retry_interval: 1
      status: 1 
    host1:
      host: 72.29.86.195
      port: 11211
      weight: 2
    host2:
      host: 66.7.208.83
      port: 11211
      weight: 2
    host3:
      host: 66.7.208.87
      port: 11211
  buckets:
    default:
      lifetime: 60
      servers: host1
    session:
      servers: [host1, host2]
    object:
      servers: [host1]
    function:
      servers: host2
    view:

In order to use YAML configuration a file named "myMemcacheConfigHandler.class.php" must be created in the /lib folder of your application.

<?php
 class myMemcacheConfigHandler extends sfYamlConfigHandler
{
  /**
   * Executes this configuration handler.
   *
   * @param array An array of absolute filesystem path to a configuration file
   *
   * @return string Data to be written to a cache file
   *
   * @throws <b>sfParseException</b> If a requested configuration file is improperly formatted
   */
  public function execute($configFiles)
  {
    // parse the yaml
    $myConfig = $this->parseYamls($configFiles);
 
    $myConfig = sfToolkit::arrayDeepMerge(
      isset($myConfig['default']) && is_array($myConfig['default']) ? $myConfig['default'] : array(),
      isset($myConfig['all']) && is_array($myConfig['all']) ? $myConfig['all'] : array(),
      isset($myConfig[sfConfig::get('sf_environment')]) && is_array($myConfig[sfConfig::get('sf_environment')]) ? $myConfig[sfConfig::get('sf_environment')] : array()
    );
 
    // Set Up Servers
    $defaultServerConfig = array('host' => 'localhost',
                            'port' => 11211,
                            'persistent' => true,
                            'weight' => 1,
                            'timeout' => 1,
                            'retry_interval' => 15,
                            'status' => true,                                        
                            );                           
 
    if(!isset($myConfig['servers']) || !is_array($myConfig['servers']))
    {
        $myConfig['servers'] = array( 'default' => $defaultServerConfig );    
    }
 
    $myConfig['servers']['default'] = array_merge( $defaultServerConfig, isset($myConfig['servers']['default']) ? $myConfig['servers']['default'] : array() );  
 
    foreach($myConfig['servers'] as $serverName => &$server)
    {
        $server = array_merge($myConfig['servers']['default'], $server);
    }
 
    // Set Up Buckets
    if(!isset($myConfig['buckets']) || !is_array($myConfig['buckets']))
        throw new sfParseException(sprintf('Configuration file "%s" does not specify any cache buckets.', $configFiles[0]));        
 
    $inits = array();
    foreach($myConfig['buckets'] as $bucketName => &$bucket)
    {
        if(!isset($bucket['servers']))
        {
            $bucket['servers'] = 'default';
        }
 
        if(!is_array($bucket['servers']))
        {
            $bucket['servers'] = array( $bucket['servers'] );            
        }
 
 
        foreach($bucket['servers'] as $serverName => &$server)
        {
            if(!isset($myConfig['servers'][$server]))
                throw new sfParseException(sprintf('Configuration file "%s" requires server configuration \'%s\' for bucket \'%s\', but server configuration does not exist.', $configFiles[0], $server, $bucketName ));
 
            $server = $myConfig['servers'][$server];        
        }
 
        $inits[] = sprintf("sfAdvMemcachedCache::createInstance('%s', %s);", $bucketName, var_export($bucket, true) );
    }
 
    // Compile Return Value    
    return sprintf("<?php\n  %s", implode("\n", $inits));
  }
}

Once that code is in place, modify your config.php in your applications /config directory.

Add the following code:

include(sfConfigCache::getInstance()->checkConfig(sfConfig::get('sf_app_config_dir_name').'/memcache.yml'));

Lastly create a file called sfAdvMemcachedCache.php in your /lib folder. All of the above is optional, and is only needed if you wanted to use YAML for auto-initialization.

... it seems there was too much code in here for a snippet. Trying to save the snippet would cause a silent failure. You can download the code here:

http://lu.scio.us/files/sfAdvMemcachedCache.php.text

Using this code as a base, it is trivial to create a Memcached class to handle session data, cache view content, or cache propel objects automatically.

The first two classes I have already written, and may be released if I repackage this code into a plugin.