107 lines
3.4 KiB
PHP
107 lines
3.4 KiB
PHP
<?php
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/**
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; under version 2
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* of the License (non-upgradable).
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*
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* Copyright (c) 2017 (original work) Open Assessment Technologies SA (under the project TAO-PRODUCT);
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*
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*/
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namespace oat\taoTaskQueue\model\TaskSelector;
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use oat\oatbox\log\LoggerAwareTrait;
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use oat\oatbox\PhpSerializeStateless;
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use oat\tao\model\taskQueue\Queue\TaskSelector\SelectorStrategyInterface;
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use oat\tao\model\taskQueue\QueueInterface;
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use Psr\Log\LoggerAwareInterface;
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/**
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* Walking through all the queues having respect for the priorities.
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*
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* 1: generating a list of queues in the order of weights
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* 2: get a queue by the current index (starting with the highest priority queue always)
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* 3a: IF there is a task in the current queue, let's process it and restart form point 2
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* 3b: IF there is no task go to the next queue and repeat from point 2
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* 3c: IF there is no task and we have a complete iteration, sleep a while and repeat from point 2
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*
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* @author Gyula Szucs <gyula@taotesting.com>
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*/
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class StrictPriorityStrategy implements SelectorStrategyInterface, LoggerAwareInterface
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{
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use LoggerAwareTrait;
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use PhpSerializeStateless;
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/**
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* @var QueueInterface[]
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*/
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private $sortedQueues = [];
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private $nextQueueIndex = 0;
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/**
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* @inheritdoc
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*/
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public function pickNextTask(array $queues)
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{
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$this->sortQueues($queues);
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// if the next index is bigger than the max index
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if ($this->nextQueueIndex > count($this->sortedQueues) - 1) {
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$this->nextQueueIndex = 0;
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}
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$pickedQueue = $this->sortedQueues[$this->nextQueueIndex];
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$this->logDebug('Queue "' . strtoupper($pickedQueue->getName()) . '" picked by StrictPriorityStrategy');
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$task = $pickedQueue->dequeue();
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if (is_null($task)) {
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// let's use the next queue in the next iteration
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$this->nextQueueIndex++;
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} else {
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// always start with the first queue after having a task from any queue
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$this->nextQueueIndex = 0;
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}
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return $task;
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}
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/**
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* @return int
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*/
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public function getWaitTime()
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{
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// sleeping 5 sec only after a complete iteration (every queue has been selected once in a row), otherwise 0 sec
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return $this->nextQueueIndex - 1 == count($this->sortedQueues) - 1 ? 5 : 0;
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}
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/**
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* @param QueueInterface[] $queues
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*/
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private function sortQueues(array $queues)
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{
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usort($queues, function (QueueInterface $queueA, QueueInterface $queueB) {
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if ($queueA->getWeight() == $queueB->getWeight()) {
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return 0;
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}
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return ($queueB->getWeight() < $queueA->getWeight()) ? -1 : 1;
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});
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$this->sortedQueues = $queues;
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}
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}
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