MediaWiki 1.30.2

[autoinstallsdev/mediawiki.git] / includes / libs / stats / SamplingStatsdClient.php

diff --git a/includes/libs/stats/SamplingStatsdClient.php b/includes/libs/stats/SamplingStatsdClient.php
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+<?php
+/**
+ * Copyright 2015
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ * http://www.gnu.org/copyleft/gpl.html
+ *
+ * @file
+ */
+
+use Liuggio\StatsdClient\StatsdClient;
+use Liuggio\StatsdClient\Entity\StatsdData;
+use Liuggio\StatsdClient\Entity\StatsdDataInterface;
+
+/**
+ * A statsd client that applies the sampling rate to the data items before sending them.
+ *
+ * @since 1.26
+ */
+class SamplingStatsdClient extends StatsdClient {
+       protected $samplingRates = [];
+
+       /**
+        * Sampling rates as an associative array of patterns and rates.
+        * Patterns are Unix shell patterns (e.g. 'MediaWiki.api.*').
+        * Rates are sampling probabilities (e.g. 0.1 means 1 in 10 events are sampled).
+        * @param array $samplingRates
+        * @since 1.28
+        */
+       public function setSamplingRates( array $samplingRates ) {
+               $this->samplingRates = $samplingRates;
+       }
+
+       /**
+        * Sets sampling rate for all items in $data.
+        * The sample rate specified in a StatsdData entity overrides the sample rate specified here.
+        *
+        * @inheritDoc
+        */
+       public function appendSampleRate( $data, $sampleRate = 1 ) {
+               $samplingRates = $this->samplingRates;
+               if ( !$samplingRates && $sampleRate !== 1 ) {
+                       $samplingRates = [ '*' => $sampleRate ];
+               }
+               if ( $samplingRates ) {
+                       array_walk( $data, function ( $item ) use ( $samplingRates ) {
+                               /** @var StatsdData $item */
+                               foreach ( $samplingRates as $pattern => $rate ) {
+                                       if ( fnmatch( $pattern, $item->getKey(), FNM_NOESCAPE ) ) {
+                                               $item->setSampleRate( $item->getSampleRate() * $rate );
+                                               break;
+                                       }
+                               }
+                       } );
+               }
+
+               return $data;
+       }
+
+       /**
+        * Send the metrics over UDP
+        * Sample the metrics according to their sample rate and send the remaining ones.
+        *
+        * @param StatsdDataInterface|StatsdDataInterface[] $data message(s) to sent
+        *        strings are not allowed here as sampleData requires a StatsdDataInterface
+        * @param int $sampleRate
+        *
+        * @return int the data sent in bytes
+        */
+       public function send( $data, $sampleRate = 1 ) {
+               if ( !is_array( $data ) ) {
+                       $data = [ $data ];
+               }
+               if ( !$data ) {
+                       return;
+               }
+               foreach ( $data as $item ) {
+                       if ( !( $item instanceof StatsdDataInterface ) ) {
+                               throw new InvalidArgumentException(
+                                       'SamplingStatsdClient does not accept stringified messages' );
+                       }
+               }
+
+               // add sampling
+               $data = $this->appendSampleRate( $data, $sampleRate );
+               $data = $this->sampleData( $data );
+
+               $data = array_map( 'strval', $data );
+
+               // reduce number of packets
+               if ( $this->getReducePacket() ) {
+                       $data = $this->reduceCount( $data );
+               }
+
+               // failures in any of this should be silently ignored if ..
+               $written = 0;
+               try {
+                       $fp = $this->getSender()->open();
+                       if ( !$fp ) {
+                               return;
+                       }
+                       foreach ( $data as $message ) {
+                               $written += $this->getSender()->write( $fp, $message );
+                       }
+                       $this->getSender()->close( $fp );
+               } catch ( Exception $e ) {
+                       $this->throwException( $e );
+               }
+
+               return $written;
+       }
+
+       /**
+        * Throw away some of the data according to the sample rate.
+        * @param StatsdDataInterface[] $data
+        * @return StatsdDataInterface[]
+        * @throws LogicException
+        */
+       protected function sampleData( $data ) {
+               $newData = [];
+               $mt_rand_max = mt_getrandmax();
+               foreach ( $data as $item ) {
+                       $samplingRate = $item->getSampleRate();
+                       if ( $samplingRate <= 0.0 || $samplingRate > 1.0 ) {
+                               throw new LogicException( 'Sampling rate shall be within ]0, 1]' );
+                       }
+                       if (
+                               $samplingRate === 1 ||
+                               ( mt_rand() / $mt_rand_max <= $samplingRate )
+                       ) {
+                               $newData[] = $item;
+                       }
+               }
+               return $newData;
+       }
+
+       /**
+        * @inheritDoc
+        */
+       protected function throwException( Exception $exception ) {
+               if ( !$this->getFailSilently() ) {
+                       throw $exception;
+               }
+       }
+}