Stats: add copy to statsd feature

Enables copying a metric to statsd at the specified namespace.

Bug: T240685
Change-Id: I15d6f100a31fbb98ad89568a2024e926cb47f937

includes/ServiceWiring.php

@@ -1957,7 +1957,8 @@ return [
 			\Wikimedia\Stats\OutputFormats::getNewFormatter( $format ),
 			$config->get( MainConfigNames::StatsTarget )
 		);
-		return new StatsFactory( 'core', $cache, $emitter, LoggerFactory::getInstance( 'Stats' ) );
+		$factory = new StatsFactory( 'core', $cache, $emitter, LoggerFactory::getInstance( 'Stats' ) );
+		return $factory->withStatsdDataFactory( $services->getStatsdDataFactory() );
 	},
 
 	'TalkPageNotificationManager' => static function (

includes/libs/Stats/Metrics/BaseMetric.php

@@ -21,6 +21,7 @@ declare( strict_types=1 );
 
 namespace Wikimedia\Stats\Metrics;
 
+use IBufferingStatsdDataFactory;
 use Wikimedia\Stats\Exceptions\IllegalOperationException;
 use Wikimedia\Stats\Sample;
 use Wikimedia\Stats\StatsUtils;
@@ -61,6 +62,9 @@ class BaseMetric implements BaseMetricInterface {
 	/** @var Sample[] */
 	private array $samples = [];
 
+	/** @var IBufferingStatsdDataFactory|null */
+	private ?IBufferingStatsdDataFactory $statsdDataFactory = null;
+
 	/** @inheritDoc */
 	public function __construct( string $component, string $name ) {
 		$this->component = $component;
@@ -113,6 +117,17 @@ class BaseMetric implements BaseMetricInterface {
 		$this->workingLabels[$key] = StatsUtils::normalizeString( $value );
 	}
 
+	/** @inheritDoc */
+	public function getStatsdDataFactory() {
+		return $this->statsdDataFactory;
+	}
+
+	/** @inheritDoc */
+	public function withStatsdDataFactory( $statsdDataFactory ): BaseMetric {
+		$this->statsdDataFactory = $statsdDataFactory;
+		return $this;
+	}
+
 	/**
 	 * Registers a label key
 	 *

includes/libs/Stats/Metrics/BaseMetricInterface.php

@@ -21,6 +21,7 @@ declare( strict_types=1 );
 
 namespace Wikimedia\Stats\Metrics;
 
+use IBufferingStatsdDataFactory;
 use Wikimedia\Stats\Sample;
 
 /**
@@ -120,4 +121,17 @@ interface BaseMetricInterface {
 	 * @return void
 	 */
 	public function clearLabels(): void;
+
+	/**
+	 * Gets StatsD Data Factory instance or null.
+	 */
+	public function getStatsdDataFactory();
+
+	/**
+	 * StatsD Data Factory instance to copy metrics to.
+	 *
+	 * @param IBufferingStatsdDataFactory $statsdDataFactory
+	 * @return BaseMetricInterface
+	 */
+	public function withStatsdDataFactory( IBufferingStatsdDataFactory $statsdDataFactory );
 }

includes/libs/Stats/Metrics/CounterMetric.php

@@ -45,6 +45,9 @@ class CounterMetric implements MetricInterface {
 	 */
 	private const TYPE_INDICATOR = "c";
 
+	/** @var string|null */
+	private ?string $statsdNamespace = null;
+
 	/** @var BaseMetricInterface */
 	private BaseMetricInterface $baseMetric;
 
@@ -74,6 +77,10 @@ class CounterMetric implements MetricInterface {
 	 * @return void
 	 */
 	public function incrementBy( int $value, array $labels = [] ): void {
+		if ( $this->statsdNamespace !== null ) {
+			$this->baseMetric->getStatsdDataFactory()->updateCount( $this->statsdNamespace, $value );
+			$this->statsdNamespace = null;
+		}
 		$this->baseMetric->addSample( new Sample( $this->baseMetric->getLabelValues(), $value ) );
 	}
 
@@ -131,6 +138,14 @@ class CounterMetric implements MetricInterface {
 		return $this;
 	}
 
+	/** @inheritDoc */
+	public function copyToStatsdAt( string $statsdNamespace ): CounterMetric {
+		if ( $this->baseMetric->getStatsdDataFactory() !== null ) {
+			$this->statsdNamespace = $statsdNamespace;
+		}
+		return $this;
+	}
+
 	/** @inheritDoc */
 	public function fresh(): CounterMetric {
 		$this->baseMetric->clearLabels();

includes/libs/Stats/Metrics/GaugeMetric.php

@@ -45,6 +45,9 @@ class GaugeMetric implements MetricInterface {
 	 */
 	private const TYPE_INDICATOR = "g";
 
+	/** @var string|null */
+	private ?string $statsdNamespace = null;
+
 	/** @var BaseMetricInterface */
 	private BaseMetricInterface $baseMetric;
 
@@ -64,6 +67,10 @@ class GaugeMetric implements MetricInterface {
 	 * @return void
 	 */
 	public function set( float $value ): void {
+		if ( $this->statsdNamespace !== null ) {
+			$this->baseMetric->getStatsdDataFactory()->updateCount( $this->statsdNamespace, $value );
+			$this->statsdNamespace = null;
+		}
 		$this->baseMetric->addSample( new Sample( $this->baseMetric->getLabelValues(), $value ) );
 	}
 
@@ -121,6 +128,14 @@ class GaugeMetric implements MetricInterface {
 		return $this;
 	}
 
+	/** @inheritDoc */
+	public function copyToStatsdAt( string $statsdNamespace ) {
+		if ( $this->baseMetric->getStatsdDataFactory() !== null ) {
+			$this->statsdNamespace = $statsdNamespace;
+		}
+		return $this;
+	}
+
 	/** @inheritDoc */
 	public function fresh(): GaugeMetric {
 		$this->baseMetric->clearLabels();

includes/libs/Stats/Metrics/MetricInterface.php

@@ -78,6 +78,14 @@ interface MetricInterface {
 	 */
 	public function withLabel( string $key, string $value );
 
+	/**
+	 * Copies metric operation to StatsD at provided namespace.
+	 *
+	 * @param string $statsdNamespace
+	 * @return CounterMetric|GaugeMetric|TimingMetric|NullMetric
+	 */
+	public function copyToStatsdAt( string $statsdNamespace );
+
 	/**
 	 * Returns metric with cleared labels.
 	 *

includes/libs/Stats/Metrics/TimingMetric.php

@@ -46,6 +46,9 @@ class TimingMetric implements MetricInterface {
 	 */
 	private const TYPE_INDICATOR = "ms";
 
+	/** @var string|null */
+	private ?string $statsdNamespace = null;
+
 	/** @var BaseMetricInterface */
 	private BaseMetricInterface $baseMetric;
 
@@ -91,6 +94,10 @@ class TimingMetric implements MetricInterface {
 	 * @return void
 	 */
 	public function observe( float $value ): void {
+		if ( $this->statsdNamespace !== null ) {
+			$this->baseMetric->getStatsdDataFactory()->timing( $this->statsdNamespace, $value );
+			$this->statsdNamespace = null;
+		}
 		$this->baseMetric->addSample( new Sample( $this->baseMetric->getLabelValues(), $value ) );
 	}
 
@@ -148,6 +155,14 @@ class TimingMetric implements MetricInterface {
 		return $this;
 	}
 
+	/** @inheritDoc */
+	public function copyToStatsdAt( string $statsdNamespace ) {
+		if ( $this->baseMetric->getStatsdDataFactory() !== null ) {
+			$this->statsdNamespace = $statsdNamespace;
+		}
+		return $this;
+	}
+
 	/** @inheritDoc */
 	public function fresh(): TimingMetric {
 		$this->baseMetric->clearLabels();

includes/libs/Stats/StatsFactory.php

@@ -21,6 +21,7 @@ declare( strict_types=1 );
 
 namespace Wikimedia\Stats;
 
+use IBufferingStatsdDataFactory;
 use InvalidArgumentException;
 use Psr\Log\LoggerInterface;
 use TypeError;
@@ -63,6 +64,9 @@ class StatsFactory {
 	/** @var LoggerInterface */
 	private LoggerInterface $logger;
 
+	/** @var IBufferingStatsdDataFactory|null */
+	private ?IBufferingStatsdDataFactory $statsdDataFactory = null;
+
 	/**
 	 * StatsFactory builds, configures, and caches Metrics.
 	 *
@@ -113,6 +117,11 @@ class StatsFactory {
 		return $this;
 	}
 
+	public function withStatsdDataFactory( IBufferingStatsdDataFactory $statsdDataFactory ): StatsFactory {
+		$this->statsdDataFactory = $statsdDataFactory;
+		return $this;
+	}
+
 	/**
 	 * Makes a new CounterMetric or fetches one from cache.
 	 *
@@ -179,7 +188,9 @@ class StatsFactory {
 		if ( $metric === null ) {
 			$baseMetric = new BaseMetric( $this->component, $name );
 			$metric = new $className(
-				$baseMetric->withStaticLabels( $this->staticLabelKeys, $this->staticLabelValues ),
+				$baseMetric
+					->withStatsdDataFactory( $this->statsdDataFactory )
+					->withStaticLabels( $this->staticLabelKeys, $this->staticLabelValues ),
 				$this->logger
 			);
 			$this->cache->set( $this->component, $name, $metric );

tests/phpunit/unit/includes/libs/Stats/StatsEmitterTest.php

@@ -2,6 +2,7 @@
 
 namespace Wikimedia\Tests\Stats;
 
+use IBufferingStatsdDataFactory;
 use PHPUnit\Framework\TestCase;
 use Psr\Log\NullLogger;
 use UDPTransport;
@@ -19,6 +20,10 @@ use Wikimedia\Stats\StatsFactory;
 class StatsEmitterTest extends TestCase {
 
 	public function testSend() {
+		// set up a mock statsd data factory
+		$statsd = $this->createMock( IBufferingStatsdDataFactory::class );
+		$statsd->expects( $this->exactly( 1 ) )->method( "updateCount" );
+
 		// initialize cache
 		$cache = new StatsCache();
 
@@ -40,7 +45,11 @@ class StatsEmitterTest extends TestCase {
 		// initialize metrics factory
 		$m = new StatsFactory( 'test', $cache, $emitter, new NullLogger );
 
-		$m->getCounter( 'bar' )->increment();
+		// inject statsd factory
+		$m->withStatsdDataFactory( $statsd );
+
+		// populate metric with statsd copy
+		$m->getCounter( 'bar' )->copyToStatsdAt( 'test.metric' )->increment();
 
 		// fetch same metric from cache and use it
 		$metric = $m->getCounter( 'bar' );