88 lines
2.7 KiB
PHP
88 lines
2.7 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\taoTaskQueue\model\QueueInterface;
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use Psr\Log\LoggerAwareInterface;
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/**
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* Implements a strategy for selecting a queue randomly taking into account the known weights.
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*
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* @deprecated Use \oat\tao\model\taskQueue\Queue\TaskSelector\WeightStrategy
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*
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* @author Gyula Szucs <gyula@taotesting.com>
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*/
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class WeightStrategy 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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* @inheritdoc
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*/
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public function pickNextTask(array $queues)
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{
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$pickedQueue = $this->pickQueueByWight($queues);
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$this->logDebug('Queue "' . strtoupper($pickedQueue->getName()) . '" picked by WeightStrategy');
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return $pickedQueue->dequeue();
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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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return 1;
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}
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/**
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* Picks randomly a queue based on weight.
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*
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* For example, an array like ['A'=>5, 'B'=>45, 'C'=>50] means that "A" has a 5% chance of being selected, "B" 45%, and "C" 50%.
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* The values are simply relative to each other. If one value weight was 2, and the other weight of 1,
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* the value with the weight of 2 has about a 66% chance of being selected.
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*
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* @inheritdoc
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*/
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private function pickQueueByWight(array $queues)
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{
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$weights = array_map(function (QueueInterface $queue) {
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return $queue->getWeight();
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}, $queues);
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$rand = mt_rand(1, array_sum($weights));
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/** @var QueueInterface $queue */
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foreach ($queues as $queue) {
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$rand -= $queue->getWeight();
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if ($rand <= 0) {
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return $queue;
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}
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}
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}
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}
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