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Direktori : /home2/selectio/www/myclassicfit.com-1/vendor/aws/aws-sdk-php/src/Retry/ |
Current File : /home2/selectio/www/myclassicfit.com-1/vendor/aws/aws-sdk-php/src/Retry/RateLimiter.php |
<?php namespace Aws\Retry; /** * @internal */ class RateLimiter { // User-configurable constants private $beta; private $minCapacity; private $minFillRate; private $scaleConstant; private $smooth; // Optional callable time provider private $timeProvider; // Pre-set state variables private $currentCapacity = 0; private $enabled = false; private $lastMaxRate = 0; private $measuredTxRate = 0; private $requestCount = 0; // Other state variables private $fillRate; private $lastThrottleTime; private $lastTimestamp; private $lastTxRateBucket; private $maxCapacity; private $timeWindow; public function __construct($options = []) { $this->beta = isset($options['beta']) ? $options['beta'] : 0.7; $this->minCapacity = isset($options['min_capacity']) ? $options['min_capacity'] : 1; $this->minFillRate = isset($options['min_fill_rate']) ? $options['min_fill_rate'] : 0.5; $this->scaleConstant = isset($options['scale_constant']) ? $options['scale_constant'] : 0.4; $this->smooth = isset($options['smooth']) ? $options['smooth'] : 0.8; $this->timeProvider = isset($options['time_provider']) ? $options['time_provider'] : null; $this->lastTxRateBucket = floor($this->time()); $this->lastThrottleTime = $this->time(); } public function isEnabled() { return $this->enabled; } public function getSendToken() { $this->acquireToken(1); } public function updateSendingRate($isThrottled) { $this->updateMeasuredRate(); if ($isThrottled) { if (!$this->isEnabled()) { $rateToUse = $this->measuredTxRate; } else { $rateToUse = min($this->measuredTxRate, $this->fillRate); } $this->lastMaxRate = $rateToUse; $this->calculateTimeWindow(); $this->lastThrottleTime = $this->time(); $calculatedRate = $this->cubicThrottle($rateToUse); $this->enableTokenBucket(); } else { $this->calculateTimeWindow(); $calculatedRate = $this->cubicSuccess($this->time()); } $newRate = min($calculatedRate, 2 * $this->measuredTxRate); $this->updateTokenBucketRate($newRate); return $newRate; } private function acquireToken($amount) { if (!$this->enabled) { return true; } $this->refillTokenBucket(); if ($amount > $this->currentCapacity) { usleep((int) (1000000 * ($amount - $this->currentCapacity) / $this->fillRate)); } $this->currentCapacity -= $amount; return true; } private function calculateTimeWindow() { $this->timeWindow = pow(($this->lastMaxRate * (1 - $this->beta) / $this->scaleConstant), 0.333); } private function cubicSuccess($timestamp) { $dt = $timestamp - $this->lastThrottleTime; return $this->scaleConstant * pow($dt - $this->timeWindow, 3) + $this->lastMaxRate; } private function cubicThrottle($rateToUse) { return $rateToUse * $this->beta; } private function enableTokenBucket() { $this->enabled = true; } private function refillTokenBucket() { $timestamp = $this->time(); if (!isset($this->lastTimestamp)) { $this->lastTimestamp = $timestamp; return; } $fillAmount = ($timestamp - $this->lastTimestamp) * $this->fillRate; $this->currentCapacity = $this->currentCapacity + $fillAmount; if (!is_null($this->maxCapacity)) { $this->currentCapacity = min( $this->maxCapacity, $this->currentCapacity ); } $this->lastTimestamp = $timestamp; } private function time() { if (is_callable($this->timeProvider)) { $provider = $this->timeProvider; $time = $provider(); return $time; } return microtime(true); } private function updateMeasuredRate() { $timestamp = $this->time(); $timeBucket = floor(round($timestamp, 3) * 2) / 2; $this->requestCount++; if ($timeBucket > $this->lastTxRateBucket) { $currentRate = $this->requestCount / ($timeBucket - $this->lastTxRateBucket); $this->measuredTxRate = ($currentRate * $this->smooth) + ($this->measuredTxRate * (1 - $this->smooth)); $this->requestCount = 0; $this->lastTxRateBucket = $timeBucket; } } private function updateTokenBucketRate($newRps) { $this->refillTokenBucket(); $this->fillRate = max($newRps, $this->minFillRate); $this->maxCapacity = max($newRps, $this->minCapacity); $this->currentCapacity = min($this->currentCapacity, $this->maxCapacity); } }