wikimedia/mediawiki-extensions-Wikibase

<?php

namespace Wikibase\Client\DataAccess\Scribunto;

use InvalidArgumentException;
use Liuggio\StatsdClient\Factory\StatsdDataFactoryInterface;

/**
 * Helper for tracking accesses of Lua functions.
 *
 * @license GPL-2.0-or-later
 * @author Marius Hoch
 */
class LuaFunctionCallTracker {

    /**
     * @var StatsdDataFactoryInterface
     */
    private $statsdDataFactory;

    /**
     * @var string
     */
    private $siteId;

    /**
     * @var string
     */
    private $siteGroup;

    /**
     * @var bool
     */
    private $trackLuaFunctionCallsPerSiteGroup;

    /**
     * @var bool
     */
    private $trackLuaFunctionCallsPerWiki;

    /**
     * @var float
     */
    private $sampleRate;

    /**
     * @param StatsdDataFactoryInterface $statsdDataFactory
     * @param string $siteId
     * @param string $siteGroup
     * @param bool $trackLuaFunctionCallsPerSiteGroup
     * @param bool $trackLuaFunctionCallsPerWiki
     * @param float $sampleRate A number in the range of [0, 1], representing
     *   the fraction of counter increments that will be reported from Lua.
     */
    public function __construct(
        StatsdDataFactoryInterface $statsdDataFactory,
        $siteId,
        $siteGroup,
        $trackLuaFunctionCallsPerSiteGroup,
        $trackLuaFunctionCallsPerWiki,
        $sampleRate
    ) {
        $this->statsdDataFactory = $statsdDataFactory;
        $this->siteId = $siteId;
        $this->siteGroup = $siteGroup;
        $this->trackLuaFunctionCallsPerSiteGroup = $trackLuaFunctionCallsPerSiteGroup;
        $this->trackLuaFunctionCallsPerWiki = $trackLuaFunctionCallsPerWiki;
        if ( $sampleRate < 0 || $sampleRate > 1 ) {
            throw new InvalidArgumentException( '$sampleRate must be between 0 and 1.' );
        }
        $this->sampleRate = $sampleRate;
    }

    /**
     * Prefix and increment the given statsd key.
     *
     * @param string $key
     */
    public function incrementKey( $key ) {
        if ( $this->sampleRate === 0 ) {
            return;
        }
        $prefixedKeys = $this->getPrefixedKeys( $key );
        $count = intval( 1 / $this->sampleRate );

        foreach ( $prefixedKeys as $prefixedKey ) {
            $this->statsdDataFactory->updateCount( $prefixedKey, $count );
        }
    }

    /**
     * @param string $key
     * @return string[]
     */
    private function getPrefixedKeys( $key ) {
        $prefixedKeys = [];

        if ( $this->trackLuaFunctionCallsPerWiki ) {
            $prefixedKeys[] = "$this->siteId.$key";
        }
        if ( $this->trackLuaFunctionCallsPerSiteGroup ) {
            $prefixedKeys[] = "$this->siteGroup.$key";
        }

        return $prefixedKeys;
    }

}