Refactor Statsd classes to enable null collector to work.

The following changes are added:
- Created MediawikiStatsdDataFactory interface
- Added hasData() method to see if there are any data to send
- Added getData() method to fetch data
- Made service infrastructure use MediawikiStatsdDataFactory interface
- Made wfLogProfilingData() use MediawikiStatsdDataFactory interface
- Added capability to enable/disable buffering collector

Bug: T166354
Change-Id: I2874175647e987996a9a399829b3319674471aaa

autoload.php

@@ -960,6 +960,7 @@ $wgAutoloadLocalClasses = [
 	'MediaWiki\\Widget\\TitleInputWidget' => __DIR__ . '/includes/widget/TitleInputWidget.php',
 	'MediaWiki\\Widget\\UserInputWidget' => __DIR__ . '/includes/widget/UserInputWidget.php',
 	'MediaWiki\\Widget\\UsersMultiselectWidget' => __DIR__ . '/includes/widget/UsersMultiselectWidget.php',
+	'MediawikiStatsdDataFactory' => __DIR__ . '/includes/libs/stats/MediawikiStatsdDataFactory.php',
 	'MemCachedClientforWiki' => __DIR__ . '/includes/compat/MemcachedClientCompat.php',
 	'MemcLockManager' => __DIR__ . '/includes/libs/lockmanager/MemcLockManager.php',
 	'MemcachedBagOStuff' => __DIR__ . '/includes/libs/objectcache/MemcachedBagOStuff.php',

includes/GlobalFunctions.php

@@ -1191,7 +1191,8 @@ function wfLogProfilingData() {
 	$profiler->logData();
 
 	$config = $context->getConfig();
-	if ( $config->get( 'StatsdServer' ) ) {
+	$stats = MediaWikiServices::getInstance()->getStatsdDataFactory();
+	if ( $config->get( 'StatsdServer' ) && $stats->hasData() ) {
 		try {
 			$statsdServer = explode( ':', $config->get( 'StatsdServer' ) );
 			$statsdHost = $statsdServer[0];
@@ -1199,9 +1200,7 @@ function wfLogProfilingData() {
 			$statsdSender = new SocketSender( $statsdHost, $statsdPort );
 			$statsdClient = new SamplingStatsdClient( $statsdSender, true, false );
 			$statsdClient->setSamplingRates( $config->get( 'StatsdSamplingRates' ) );
-			$statsdClient->send(
-				MediaWikiServices::getInstance()->getStatsdDataFactory()->getBuffer()
-			);
+			$statsdClient->send( $stats->getData() );
 		} catch ( Exception $ex ) {
 			MWExceptionHandler::logException( $ex );
 		}

includes/MediaWikiServices.php

@@ -9,9 +9,9 @@ use EventRelayerGroup;
 use GenderCache;
 use GlobalVarConfig;
 use Hooks;
+use MediawikiStatsdDataFactory;
 use Wikimedia\Rdbms\LBFactory;
 use LinkCache;
-use Liuggio\StatsdClient\Factory\StatsdDataFactory;
 use Wikimedia\Rdbms\LoadBalancer;
 use MediaHandlerFactory;
 use MediaWiki\Linker\LinkRenderer;
@@ -446,7 +446,7 @@ class MediaWikiServices extends ServiceContainer {
 
 	/**
 	 * @since 1.27
-	 * @return StatsdDataFactory
+	 * @return MediawikiStatsdDataFactory
 	 */
 	public function getStatsdDataFactory() {
 		return $this->getService( 'StatsdDataFactory' );

includes/context/ContextSource.php

@@ -170,7 +170,7 @@ abstract class ContextSource implements IContextSource {
 	 * @deprecated since 1.27 use a StatsdDataFactory from MediaWikiServices (preferably injected)
 	 *
 	 * @since 1.25
-	 * @return StatsdDataFactory
+	 * @return MediawikiStatsdDataFactory
 	 */
 	public function getStats() {
 		return MediaWikiServices::getInstance()->getStatsdDataFactory();

includes/context/DerivativeContext.php

@@ -109,7 +109,7 @@ class DerivativeContext extends ContextSource implements MutableContext {
 	 *
 	 * @deprecated since 1.27 use a StatsdDataFactory from MediaWikiServices (preferably injected)
 	 *
-	 * @return StatsdDataFactory
+	 * @return MediawikiStatsdDataFactory
 	 */
 	public function getStats() {
 		return MediaWikiServices::getInstance()->getStatsdDataFactory();

includes/context/IContextSource.php

@@ -131,7 +131,7 @@ interface IContextSource {
 	 * @deprecated since 1.27 use a StatsdDataFactory from MediaWikiServices (preferably injected)
 	 *
 	 * @since 1.25
-	 * @return StatsdDataFactory
+	 * @return MediawikiStatsdDataFactory
 	 */
 	public function getStats();
 

includes/context/RequestContext.php

@@ -138,7 +138,7 @@ class RequestContext implements IContextSource, MutableContext {
 	 *
 	 * @deprecated since 1.27 use a StatsdDataFactory from MediaWikiServices (preferably injected)
 	 *
-	 * @return StatsdDataFactory
+	 * @return MediawikiStatsdDataFactory
 	 */
 	public function getStats() {
 		return MediaWikiServices::getInstance()->getStatsdDataFactory();

includes/libs/stats/BufferingStatsdDataFactory.php

@@ -32,8 +32,17 @@ use Liuggio\StatsdClient\Factory\StatsdDataFactory;
  *
  * @since 1.25
  */
-class BufferingStatsdDataFactory extends StatsdDataFactory {
+class BufferingStatsdDataFactory extends StatsdDataFactory implements MediawikiStatsdDataFactory {
 	protected $buffer = [];
+	/**
+	 * Collection enabled?
+	 * @var bool
+	 */
+	protected $enabled = true;
+	/**
+	 * @var string
+	 */
+	private $prefix;
 
 	public function __construct( $prefix ) {
 		parent::__construct();
@@ -49,6 +58,7 @@ class BufferingStatsdDataFactory extends StatsdDataFactory {
 	 *
 	 * @param string $key
 	 * @since 1.26
+	 * @return string
 	 */
 	private static function normalizeMetricKey( $key ) {
 		$key = preg_replace( '/[:.]+/', '.', $key );
@@ -61,6 +71,9 @@ class BufferingStatsdDataFactory extends StatsdDataFactory {
 		$key, $value = 1, $metric = StatsdDataInterface::STATSD_METRIC_COUNT
 	) {
 		$entity = $this->produceStatsdDataEntity();
+		if ( !$this->enabled ) {
+			return $entity;
+		}
 		if ( $key !== null ) {
 			$key = self::normalizeMetricKey( "{$this->prefix}.{$key}" );
 			$entity->setKey( $key );
@@ -79,9 +92,35 @@ class BufferingStatsdDataFactory extends StatsdDataFactory {
 	}
 
 	/**
+	 * @deprecated Use getData()
 	 * @return StatsdData[]
 	 */
 	public function getBuffer() {
 		return $this->buffer;
 	}
+
+	/**
+	 * Check whether this data factory has any data.
+	 * @return boolean
+	 */
+	public function hasData() {
+		return !empty( $this->buffer );
+	}
+
+	/**
+	 * Return data from the factory.
+	 * @return StatsdData[]
+	 */
+	public function getData() {
+		return $this->buffer;
+	}
+
+	/**
+	 * Set collection enable status.
+	 * @param bool $enabled Will collection be enabled?
+	 * @return void
+	 */
+	public function setEnabled( $enabled ) {
+		$this->enabled = $enabled;
+	}
 }

includes/libs/stats/MediawikiStatsdDataFactory.php

@@ -0,0 +1,28 @@
+<?php
+use Liuggio\StatsdClient\Entity\StatsdData;
+use Liuggio\StatsdClient\Factory\StatsdDataFactoryInterface;
+
+/**
+ * Mediawiki adaptation of Statsd data factory.
+ */
+interface MediawikiStatsdDataFactory extends StatsdDataFactoryInterface {
+	/**
+	 * Check whether this data factory has any data.
+	 * @return boolean
+	 */
+	public function hasData();
+
+	/**
+	 * Return data from the factory.
+	 * @return StatsdData[]
+	 */
+	public function getData();
+
+	/**
+	 * Set collection enable status.
+	 * @param bool $enabled Will collection be enabled?
+	 * @return void
+	 */
+	public function setEnabled( $enabled );
+
+}

includes/libs/stats/NullStatsdDataFactory.php

@@ -8,7 +8,7 @@ use Liuggio\StatsdClient\Factory\StatsdDataFactoryInterface;
  * @author Addshore
  * @since 1.27
  */
-class NullStatsdDataFactory implements StatsdDataFactoryInterface {
+class NullStatsdDataFactory implements MediawikiStatsdDataFactory {
 
 	/**
 	 * This function creates a 'timing' StatsdData.
@@ -108,4 +108,28 @@ class NullStatsdDataFactory implements StatsdDataFactoryInterface {
 		return $data;
 	}
 
+	/**
+	 * Check whether this data factory has any data.
+	 * @return boolean
+	 */
+	public function hasData() {
+		return false;
+	}
+
+	/**
+	 * Return data from the factory.
+	 * @return StatsdData[]
+	 */
+	public function getData() {
+		return [];
+	}
+
+	/**
+	 * Set collection enable status.
+	 * @param bool $enabled Will collection be enabled?
+	 * @return void
+	 */
+	public function setEnabled( $enabled ) {
+		// Nothing to do, null factory is always disabled.
+	}
 }

tests/phpunit/includes/MediaWikiServicesTest.php

@@ -303,7 +303,7 @@ class MediaWikiServicesTest extends MediaWikiTestCase {
 			'MainConfig' => [ 'MainConfig', Config::class ],
 			'SiteStore' => [ 'SiteStore', SiteStore::class ],
 			'SiteLookup' => [ 'SiteLookup', SiteLookup::class ],
-			'StatsdDataFactory' => [ 'StatsdDataFactory', StatsdDataFactory::class ],
+			'StatsdDataFactory' => [ 'StatsdDataFactory', MediawikiStatsdDataFactory::class ],
 			'InterwikiLookup' => [ 'InterwikiLookup', InterwikiLookup::class ],
 			'EventRelayerGroup' => [ 'EventRelayerGroup', EventRelayerGroup::class ],
 			'SearchEngineFactory' => [ 'SearchEngineFactory', SearchEngineFactory::class ],