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WRStatsRateLimiter.php
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WRStatsRateLimiter.php
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<?php
namespace Wikimedia\WRStats;
/**
* A rate limiter with a WRStats backend
*
* @since 1.39
*/
class WRStatsRateLimiter {
/** @var StatsStore */
private $store;
/** @var array<string,LimitCondition> */
private $conditions;
/** @var array<string,array> */
private $specs;
/** @var string|string[] */
private $prefix;
/** @var float|int|null */
private $now;
/** Default number of time buckets per action */
public const BUCKET_COUNT = 30;
/**
* @internal Use WRStatsFactory::createRateLimiter instead
* @param StatsStore $store
* @param array<string,LimitCondition> $conditions
* @param string|string[] $prefix
* @param array $options
*/
public function __construct(
StatsStore $store,
$conditions,
$prefix = 'WRLimit',
$options = []
) {
$this->store = $store;
$this->conditions = $conditions;
$this->prefix = $prefix;
$bucketCount = $options['bucketCount'] ?? self::BUCKET_COUNT;
$specs = [];
foreach ( $conditions as $name => $condition ) {
$specs[$name] = [
'sequences' => [ [
'timeStep' => $condition->window / $bucketCount,
'expiry' => $condition->window
] ]
];
}
$this->specs = $specs;
}
/**
* Create a batch object for rate limiting of multiple metrics.
*
* @param int $defaultAmount The amount to increment each metric by, if no
* amount is passed to localOp/globalOp
* @return LimitBatch
*/
public function createBatch( $defaultAmount = 1 ) {
return new LimitBatch( $this, $defaultAmount );
}
/**
* Check whether executing a single operation would exceed the defined limit,
* without incrementing the count.
*
* @param string $condName
* @param EntityKey|null $entityKey
* @param int $amount
* @return LimitOperationResult
*/
public function peek(
string $condName,
?EntityKey $entityKey = null,
$amount = 1
): LimitOperationResult {
$actions = [ new LimitOperation( $condName, $entityKey, $amount ) ];
$result = $this->peekBatch( $actions );
return $result->getAllResults()[0];
}
/**
* Check whether executing a given set of increment operations would exceed
* any defined limit, without actually performing the increment.
*
* @param LimitOperation[] $operations
* @return LimitBatchResult
*/
public function peekBatch( array $operations ) {
$reader = new WRStatsReader( $this->store, $this->specs, $this->prefix );
if ( $this->now !== null ) {
$reader->setCurrentTime( $this->now );
}
$rates = [];
$amounts = [];
foreach ( $operations as $operation ) {
$name = $operation->condName;
$cond = $this->conditions[$name] ?? null;
if ( $cond === null ) {
throw new WRStatsError( "Unrecognized metric \"$name\"" );
}
if ( !isset( $rates[$name] ) ) {
$range = $reader->latest( $cond->window );
$rates[$name] = $reader->getRate( $name, $operation->entityKey, $range );
$amounts[$name] = 0;
}
$amounts[$name] += $operation->amount;
}
$results = [];
foreach ( $operations as $i => $operation ) {
$name = $operation->condName;
$total = $rates[$name]->total();
$cond = $this->conditions[$name];
$results[$i] = new LimitOperationResult(
$cond,
$total,
$total + $amounts[$name]
);
}
return new LimitBatchResult( $results );
}
/**
* Check if the limit would be exceeded by incrementing the specified
* metric. If not, increment it.
*
* @param string $condName
* @param EntityKey|null $entityKey
* @param int $amount
* @return LimitOperationResult
*/
public function tryIncr(
string $condName,
?EntityKey $entityKey = null,
$amount = 1
): LimitOperationResult {
$actions = [ new LimitOperation( $condName, $entityKey, $amount ) ];
$result = $this->tryIncrBatch( $actions );
return $result->getAllResults()[0];
}
/**
* Check if the limit would be exceeded by execution of the given set of
* increment operations. If not, perform the increments.
*
* @param LimitOperation[] $operations
* @return LimitBatchResult
*/
public function tryIncrBatch( array $operations ) {
$result = $this->peekBatch( $operations );
if ( $result->isAllowed() ) {
$this->incrBatch( $operations );
}
return $result;
}
/**
* Unconditionally increment a metric.
*
* @param string $condName
* @param EntityKey|null $entityKey
* @param int $amount
* @return void
*/
public function incr(
string $condName,
?EntityKey $entityKey = null,
$amount = 1
) {
$actions = [ new LimitOperation( $condName, $entityKey, $amount ) ];
$this->incrBatch( $actions );
}
/**
* Unconditionally increment a set of metrics.
*
* @param LimitOperation[] $operations
*/
public function incrBatch( array $operations ) {
$writer = new WRStatsWriter( $this->store, $this->specs, $this->prefix );
if ( $this->now !== null ) {
$writer->setCurrentTime( $this->now );
}
foreach ( $operations as $operation ) {
$writer->incr(
$operation->condName,
$operation->entityKey,
$operation->amount
);
}
$writer->flush();
}
/**
* Set the current time.
*
* @param float|int $now
*/
public function setCurrentTime( $now ) {
$this->now = $now;
}
/**
* Forget a time set with setCurrentTime(). Use the actual current time.
*/
public function resetCurrentTime() {
$this->now = null;
}
}

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WRStatsRateLimiter.php (5 KB)

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