Gearman addTaskBackground complete Callback doesno

I am trying to make some job in background and write result to file result from complete callback, but its only work for addTask (not in background) and not for addTaskBackground

have somebody any ideas?

thanks for help!

$client = new GearmanClient();

$client->addServer('localhost');

$client->setCompleteCallback("complete");
$client->addTaskBackground('upload', 'http://youtube.com/watch?v=o3mP3mJDL2k', null, 1);
$client->addTaskBackground('upload', 'http://www.youtube.com/watch?v=SgAVnlnf8w0', null, 2);

/* in these case complete callback works
$client->addTask('upload', 'http://youtube.com/watch?v=o3mP3mJDL2k');
$client->addTask('upload', 'http://www.youtube.com/watch?v=SgAVnlnf8w0');
*/

$client->runTasks();

function complete($task){
    file_put_contents('/home/vonica/public_html/test/tmp/1.txt', $task->unique() . ", " . $task->data() . "\n", FILE_APPEND);
}

$worker = new GearmanWorker();
$worker->addServer('localhost');

$worker->addFunction('upload', 'uploader');

while($worker->work()){
    if ($worker->returnCode() != GEARMAN_SUCCESS) {
        echo "ret code: " . $worker->returnCode() . "\n";
        break;
    }
};

function uploader($job){

   $content = $job->workload();
   exec ('echo $( youtube-dl -f worst "'.$content.'")');
   return $content;
}

CompleteCallback will not be called on background task completion. If you want to check the status of background job use GearmanClient::jobStatus.

Client.php

// save this $job_handle somewhere
$job_handle = $client->doBackground('upload', 'http://youtube.com/watch?v=o3mP3mJDL2k', null, 1);

Status.php

// use previously saved job handle to check job's status
$job_handle = $_GET['job_handle'];
$stat = $client->jobStatus($job_handle);
echo "Running: " . 
     ($stat[1] ? "true" : "false") . 
     ", numerator: " . 
     $stat[2] . 
     ", denomintor: " . 
     $stat[3] . "\n";