zend framework auth in logger in bootstrap

In my bootstrap file I initiate the logger and every thing works fine. What I need now is that the logger also logs the user_id given from the zend_auth instance. Here the logger I initiate:

public function _initLogger(){

    $resource = $this->getPluginResource('db');
$dbAdapter = $resource->getDbAdapter();
    $columnMapping = array(
        'level' => 'priorityName',
        'priority' => 'priority',
        'message' => 'message',
        'created' => 'timestamp',
        'user_agent'=> 'user_agent',
        'get_vars' => 'get_vars',
        'post_vars' => 'post_vars',
        'ip' => 'ip',
        'id_user' => 'id_user',
    );

    $auth = Zend_Auth::getInstance();

    $writerDb = new Zend_Log_Writer_Db($dbAdapter, 'tbl_log', $columnMapping);
    $logger = new Zend_Log($writerDb);

    $logger->setEventItem('datetime',date('Y-m-d H:i:s'));
    $logger->setEventItem('user_agent',$_SERVER['HTTP_USER开发者_JAVA技巧_AGENT']);
    $logger->setEventItem('get_vars',print_r($_GET,true));
    $logger->setEventItem('post_vars',print_r($_POST,true));
    $logger->setEventItem('ip',$_SERVER['REMOTE_ADDR']);
    $logger->setEventItem('id_user',$auth->getIdentity()->id);



    $logger->addPriority('login', 10);
    $logger->addPriority('logout', 11);
    $logger->addPriority('trans', 12);
    $logger->addPriority('transfailed', 13);

    Zend_Registry::set('logger', $logger);
 }

I get no error, but the user id is not stored or retrieved...

During bootstrap, auth information is not available. You need to add the lines:

$logger = Zend_Registry::get('logger');

$logger->setEventItem('id_user',$auth->getIdentity()->id);

After you get identity info from the user (in your login controller).