<?php
/**
* Interface to the external task manager.
*/
class Taskmanager
{
const NO_SUCH_TASK = 'NO_SUCH_TASK';
const TASK_FINISHED = 'TASK_FINISHED';
const TASK_ERROR = 'TASK_ERROR';
const TASK_WAITING = 'TASK_WAITING';
const NO_SUCH_INSTANCE = 'NO_SUCH_INSTANCE';
const TASK_PROCESSING = 'TASK_PROCESSING';
/**
* 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::$sock = socket_create(AF_INET, SOCK_STREAM, SOL_TCP);
if (self::$sock === false)
return;
socket_set_option(self::$sock, SOL_SOCKET, SO_SNDTIMEO, array('sec' => 1, 'usec' => 0));
if (socket_connect(self::$sock, '127.0.0.1', 9215) === false)
return;
self::send(CONFIG_TM_PASSWORD);
}
private static function send($message)
{
$len = strlen($message);
$sent = socket_send(self::$sock, pack('N', $len) . $message, $len + 4, 0);
if ($sent === $len + 4)
return true;
self::reset();
return false;
}
/**
* 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 $async if true, the function will not wait for the reply of the taskmanager, which means
* the return value is just true (and you won't know if the task could actually be started)
* @return array|false struct representing the task status (as a result of submit); false on communication error
*/
public static function submit($task, $data = false, $async = false)
{
self::init();
$seq = (string) mt_rand();
if (empty($data)) {
$data = '{}';
} else {
$data = json_encode($data);
}
$message = "$seq, $task, $data";
if (!self::send($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']) && $reply['statusCode'] === Taskmanager::NO_SUCH_TASK)) {
self::addErrorMessage($reply);
return false;
}
return $reply;
}
/**
* Query status of given task.
*
* @param mixed $task task id or task struct
* @return array|false status of task as array, or false on communication error
*/
public static function status($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, $task";
if (!self::send($message))
return false;
$reply = self::readReply($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 Taskmanager::NO_SUCH_INSTANCE/_TASK.
* If you pass an array it is assumed that it was already queried and is evaluated
* directly.
*
* @param string|array $taskid a task id or a task array returned by ::status or ::submit
* @return boolean true if taskid exists in taskmanager
*/
public static function isTask($task)
{
if ($task === false)
return false;
if (is_string($task)) {
$task = self::status($task);
}
return isset($task['statusCode']) && $task['statusCode'] !== Taskmanager::NO_SUCH_INSTANCE
&& $task['statusCode'] !== Taskmanager::NO_SUCH_TASK;
}
/**
* Wait for the given task's completion.
*
* @param string|array $task task to wait for
* @param int $timeout maximum time in ms to wait for completion of task
* @return array|false result/status of task, or false if it couldn't be queried
*/
public static function waitComplete($task, $timeout = 2500)
{
if (is_array($task) && isset($task['id'])) {
if ($task['statusCode'] !== Taskmanager::TASK_PROCESSING && $task['statusCode'] !== Taskmanager::TASK_WAITING) {
self::release($task['id']);
return $task;
}
$task = $task['id'];
}
if (!is_string($task))
return false;
$done = false;
$deadline = microtime(true) + $timeout / 1000;
while (($remaining = $deadline - microtime(true)) > 0) {
usleep(min(100000, $remaining * 100000));
$status = self::status($task);
if (!isset($status['statusCode']))
break;
if ($status['statusCode'] !== Taskmanager::TASK_PROCESSING && $status['statusCode'] !== Taskmanager::TASK_WAITING) {
$done = true;
break;
}
}
if ($done) { // For now we do this unconditionally, but maybe we want to keep them longer some time?
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|false $task struct representing task, obtained by ::status
* @return boolean true if task failed, false if finished successfully or still waiting/running
*/
public static function isFailed($task)
{
if (!is_array($task) || !isset($task['statusCode']) || !isset($task['id']))
return true;
if ($task['statusCode'] !== Taskmanager::TASK_WAITING && $task['statusCode'] !== Taskmanager::TASK_PROCESSING && $task['statusCode'] !== Taskmanager::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'] !== Taskmanager::TASK_WAITING && $task['statusCode'] !== Taskmanager::TASK_PROCESSING)
return true;
return false;
}
/**
* Check whether the given task is running, that is either waiting for execution
* or currently executing.
*
* @param array $task struct representing task, obtained by ::status
* @return boolean true if task is waiting or executing, false if waiting for execution or currently executing, no valid task, etc.
*/
public static function isRunning($task)
{
if (!is_array($task) || !isset($task['statusCode']) || !isset($task['id']))
return false;
if ($task['statusCode'] === Taskmanager::TASK_WAITING || $task['statusCode'] === Taskmanager::TASK_PROCESSING)
return true;
return false;
}
public static function addErrorMessage($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|array $task task to release. can either be its id, or a struct representing the task, as returned
* by ::submit() or ::status()
*/
public static function release($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, $task";
self::send($message);
}
/**
* Read reply from socket for given sequence number.
*
* @param string $seq
* @return mixed the decoded json data for that message as an array, or false on error
*/
private static function readReply(string $seq)
{
$tries = 0;
$deadline = microtime(true) + 2;
self::updateRecvTimeout($deadline);
while (($bytes = socket_recv(self::$sock, $buf, 4, MSG_WAITALL)) !== false) {
if ($bytes !== 4) {
error_log('TM: Short read');
self::reset();
return false;
}
$len = unpack('Nx', $buf)['x'];
if ($len < 0 || $len > 1024 * 1024) {
error_log('TM: Invalid payload length: ' . $len);
self::reset();
return false;
}
$message = '';
while ($len > 0) {
self::updateRecvTimeout($deadline);
$ret = socket_recv(self::$sock, $buf, $len, 0);
if ($ret === false) {
error_log('TM: Error reading payload');
self::reset();
return false;
}
if ($ret <= 0) {
error_log('TM: Taskmanager closed connection');
self::reset();
return false;
}
$message .= $buf;
$len -= $ret;
}
$parts = explode(',', $message, 2);
if (count($parts) !== 2) {
error_log('TM: Invalid reply, no "," in payload');
} elseif ($parts[0] === 'ERROR') {
Util::traceError('Taskmanager remote error: ' . $parts[1]);
} elseif ($parts[0] === 'WARNING') {
Message::addWarning('main.taskmanager-warning', $parts[1]);
} else {
// Do we have compressed data?
if (substr($parts[0], 0, 3) === '+z:') {
$parts[0] = substr($parts[0], 3);
$gz = true;
} else {
$gz = false;
}
// See if it's our message
if ($parts[0] === $seq) {
if ($gz) {
$parts[1] = gzinflate($parts[1]);
if ($parts[1] === false) {
error_log('TM: Invalid deflate data received');
continue;
}
}
return json_decode($parts[1], true);
}
}
if (++$tries > 10)
return false;
}
error_log('TM: Reading reply failed, socket error ' . socket_last_error());
return false;
}
/**
* Closes connection and resets the variable.
* Should be called if something goes wrong when
* sending or receiving and the send or receive
* buffer might be in an undefined state.
*/
private static function reset()
{
if (self::$sock === false)
return;
socket_close(self::$sock);
self::$sock = false;
}
/**
* @param float $deadline end time
*/
private static function updateRecvTimeout($deadline)
{
$to = $deadline - microtime(true);
if ($to <= 0) {
$to = ['sec' => 0, 'usec' => 1];
} else {
$s = (int)$to;
$to = ['sec' => $s, 'usec' => (int)(($to - $s) * 1000000)];
}
socket_set_option(self::$sock, SOL_SOCKET, SO_RCVTIMEO, $to);
}
}
