<?php
/**
* Interface to the external task manager.
*/
class Taskmanager
{
/**
* UDP socket used for communication with the task manager
* @var resource
*/
private static $sock = false;
private static function init()
{
if (self::$sock !== false)
return;
self::$sock = socket_create(AF_INET, SOCK_DGRAM, SOL_UDP);
socket_set_option(self::$sock, SOL_SOCKET, SO_RCVTIMEO, array('sec' => 0, 'usec' => 300000));
socket_set_option(self::$sock, SOL_SOCKET, SO_SNDTIMEO, array('sec' => 0, 'usec' => 200000));
socket_connect(self::$sock, '127.0.0.1', 9215);
}
/**
* Start a task via the task manager.
*
* @param string $task name of task to start
* @param array $data data to pass to the task. the structure depends on the task.
* @param boolean $async if true, the function will not wait for the reply of the taskmanager, which means
* the return value is just true (and you won't know if the task could acutally be started)
* @return array struct representing the task status (as a result of submit); false on communication error
*/
public static function submit($task, $data = false, $async = false)
{
self::init();
$seq = (string) mt_rand();
if (empty($data)) {
$data = '{}';
} else {
$data = json_encode($data);
}
$message = "$seq, $task, $data";
$sent = socket_send(self::$sock, $message, strlen($message), 0);
if ($sent != strlen($message)) {
self::addErrorMessage(false);
return false;
}
if ($async)
return true;
$reply = self::readReply($seq);
if ($reply === false || !is_array($reply) || !isset($reply['id']) || (isset($reply['statusCode']) && $reply['statusCode'] === NO_SUCH_TASK)) {
self::addErrorMessage($reply);
return false;
}
return $reply;
}
/**
* Query status of given task.
*
* @param mixed $task task id or task struct
* @return array status of task as array, or false on communication error
*/
public static function status($task)
{
if (is_array($task) && isset($task['id'])) {
$task = $task['id'];
}
if (!is_string($task))
return false;
self::init();
$seq = (string) mt_rand();
$message = "$seq, status, $task";
$sent = socket_send(self::$sock, $message, strlen($message), 0);
$reply = self::readReply($seq);
if (!is_array($reply))
return false;
return $reply;
}
/**
* Checks whether the given task id corresponds to a known task in the taskmanager.
* Returns true iff the taskmanager is reachable and the status of the task
* is different from NO_SUCH_TASK.
*
* @param string $taskid a task id
* @return boolean true if taskid exists in taskmanager
*/
public static function isTask($taskid)
{
$task = self::status($taskid);
return isset($task['statusCode']) && $task['statusCode'] !== NO_SUCH_TASK;
}
/**
* Wait for the given task's completion.
*
* @param type $task task to wait for
* @param int $timeout maximum time in ms to wait for completion of task
* @return array result/status of task, or false if it couldn't be queried
*/
public static function waitComplete($task, $timeout = 1500)
{
if (is_array($task) && isset($task['id'])) {
if ($task['statusCode'] !== TASK_PROCESSING && $task['statusCode'] !== TASK_WAITING) {
self::release($task['id']);
return $task;
}
$task = $task['id'];
}
if (!is_string($task))
return false;
$done = false;
for ($i = 0; $i < ($timeout / 150); ++$i) {
$status = self::status($task);
if (!isset($status['statusCode']))
break;
if ($status['statusCode'] !== TASK_PROCESSING && $status['statusCode'] !== TASK_WAITING) {
$done = true;
break;
}
usleep(100000);
}
if ($done)
self::release($task);
return $status;
}
/**
* Check whether the given task can be considered failed. This
* includes that the task id is invalid, etc.
*
* @param array $task struct representing task, obtained by ::status
* @return boolean true if task failed, false if finished successfully or still waiting/running
*/
public static function isFailed($task)
{
if (!is_array($task) || !isset($task['statusCode']) || !isset($task['id']))
return true;
if ($task['statusCode'] !== TASK_WAITING && $task['statusCode'] !== TASK_PROCESSING && $task['statusCode'] !== TASK_FINISHED)
return true;
return false;
}
/**
* Check whether the given task is finished, i.e. either failed or succeeded,
* but is not running, still waiting for execution or simply unknown.
*
* @param array $task struct representing task, obtained by ::status
* @return boolean true if task failed or finished, false if waiting for execution or currently executing, no valid task, etc.
*/
public static function isFinished($task)
{
if (!is_array($task) || !isset($task['statusCode']) || !isset($task['id']))
return false;
if ($task['statusCode'] !== TASK_WAITING && $task['statusCode'] !== TASK_PROCESSING)
return true;
return false;
}
public static function addErrorMessage($task)
{
static $failure = false;
if ($task === false) {
if (!$failure) {
Message::addError('main.taskmanager-error');
$failure = true;
}
return;
}
if (!isset($task['statusCode'])) {
Message::addError('main.taskmanager-format');
return;
}
if (isset($task['data']['error'])) {
Message::addError('main.task-error', $task['statusCode'] . ' (' . $task['data']['error'] . ')');
return;
}
Message::addError('main.task-error', $task['statusCode']);
}
/**
* Release a given task from the task manager, so it won't keep the result anymore in case it's finished running.
*
* @param string $task task to release. can either be its id, or a struct representing the task, as returned
* by ::submit() or ::status()
*/
public static function release($task)
{
if (is_array($task) && isset($task['id'])) {
$task = $task['id'];
}
if (!is_string($task))
return;
self::init();
$seq = (string) mt_rand();
$message = "$seq, release, $task";
socket_send(self::$sock, $message, strlen($message), 0);
}
/**
* Read reply from socket for given sequence number.
*
* @param string $seq
* @return mixed the decoded json data for that message as an array, or null on error
*/
private static function readReply($seq)
{
$tries = 0;
while (($bytes = socket_recvfrom(self::$sock, $buf, 90000, 0, $bla1, $bla2)) !== false || socket_last_error() === 11) {
$parts = explode(',', $buf, 2);
if (count($parts) == 2 && $parts[0] == $seq) {
return json_decode($parts[1], true);
}
if (++$tries > 10)
return false;
}
return false;
}
}
foreach (array('TASK_FINISHED', 'TASK_ERROR', 'TASK_WAITING', 'NO_SUCH_TASK', 'TASK_PROCESSING') as $i) {
define($i, $i);
}
