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| 1 | <?php |
| 2 | /** |
| 3 | * Copyright 2015 |
| 4 | * |
| 5 | * This program is free software; you can redistribute it and/or modify |
| 6 | * it under the terms of the GNU General Public License as published by |
| 7 | * the Free Software Foundation; either version 2 of the License, or |
| 8 | * (at your option) any later version. |
| 9 | * |
| 10 | * This program is distributed in the hope that it will be useful, |
| 11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 13 | * GNU General Public License for more details. |
| 14 | * |
| 15 | * You should have received a copy of the GNU General Public License along |
| 16 | * with this program; if not, write to the Free Software Foundation, Inc., |
| 17 | * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. |
| 18 | * http://www.gnu.org/copyleft/gpl.html |
| 19 | * |
| 20 | * @file |
| 21 | */ |
| 22 | |
| 23 | use Liuggio\StatsdClient\Entity\StatsdData; |
| 24 | use Liuggio\StatsdClient\Entity\StatsdDataInterface; |
| 25 | use Liuggio\StatsdClient\StatsdClient; |
| 26 | use Wikimedia\RequestTimeout\TimeoutException; |
| 27 | |
| 28 | /** |
| 29 | * A statsd client that applies the sampling rate to the data items before sending them. |
| 30 | * |
| 31 | * @since 1.26 |
| 32 | */ |
| 33 | class SamplingStatsdClient extends StatsdClient { |
| 34 | protected $samplingRates = []; |
| 35 | |
| 36 | /** |
| 37 | * Sampling rates as an associative array of patterns and rates. |
| 38 | * Patterns are Unix shell patterns (e.g. 'MediaWiki.api.*'). |
| 39 | * Rates are sampling probabilities (e.g. 0.1 means 1 in 10 events are sampled). |
| 40 | * @param array $samplingRates |
| 41 | * @since 1.28 |
| 42 | */ |
| 43 | public function setSamplingRates( array $samplingRates ) { |
| 44 | $this->samplingRates = $samplingRates; |
| 45 | } |
| 46 | |
| 47 | /** |
| 48 | * Sets sampling rate for all items in $data. |
| 49 | * The sample rate specified in a StatsdData entity overrides the sample rate specified here. |
| 50 | * |
| 51 | * @inheritDoc |
| 52 | */ |
| 53 | public function appendSampleRate( $data, $sampleRate = 1 ) { |
| 54 | $samplingRates = $this->samplingRates; |
| 55 | if ( !$samplingRates && $sampleRate !== 1 ) { |
| 56 | $samplingRates = [ '*' => $sampleRate ]; |
| 57 | } |
| 58 | if ( $samplingRates ) { |
| 59 | array_walk( $data, static function ( $item ) use ( $samplingRates ) { |
| 60 | /** @var StatsdData $item */ |
| 61 | foreach ( $samplingRates as $pattern => $rate ) { |
| 62 | if ( fnmatch( $pattern, $item->getKey(), FNM_NOESCAPE ) ) { |
| 63 | $item->setSampleRate( $item->getSampleRate() * $rate ); |
| 64 | break; |
| 65 | } |
| 66 | } |
| 67 | } ); |
| 68 | } |
| 69 | |
| 70 | return $data; |
| 71 | } |
| 72 | |
| 73 | /** |
| 74 | * Send the metrics over UDP |
| 75 | * Sample the metrics according to their sample rate and send the remaining ones. |
| 76 | * |
| 77 | * @param StatsdDataInterface|StatsdDataInterface[] $data message(s) to sent |
| 78 | * strings are not allowed here as sampleData requires a StatsdDataInterface |
| 79 | * @param int $sampleRate |
| 80 | * |
| 81 | * @return int the data sent in bytes |
| 82 | */ |
| 83 | public function send( $data, $sampleRate = 1 ) { |
| 84 | if ( !is_array( $data ) ) { |
| 85 | $data = [ $data ]; |
| 86 | } |
| 87 | if ( !$data ) { |
| 88 | return 0; |
| 89 | } |
| 90 | foreach ( $data as $item ) { |
| 91 | if ( !( $item instanceof StatsdDataInterface ) ) { |
| 92 | throw new InvalidArgumentException( |
| 93 | 'SamplingStatsdClient does not accept stringified messages' ); |
| 94 | } |
| 95 | } |
| 96 | |
| 97 | // add sampling |
| 98 | $data = $this->appendSampleRate( $data, $sampleRate ); |
| 99 | $data = $this->sampleData( $data ); |
| 100 | |
| 101 | $data = array_map( 'strval', $data ); |
| 102 | |
| 103 | // reduce number of packets |
| 104 | if ( $this->getReducePacket() ) { |
| 105 | $data = $this->reduceCount( $data ); |
| 106 | } |
| 107 | |
| 108 | // failures in any of this should be silently ignored if .. |
| 109 | $written = 0; |
| 110 | try { |
| 111 | $fp = $this->getSender()->open(); |
| 112 | if ( !$fp ) { |
| 113 | return 0; |
| 114 | } |
| 115 | foreach ( $data as $message ) { |
| 116 | $written += $this->getSender()->write( $fp, $message ); |
| 117 | } |
| 118 | $this->getSender()->close( $fp ); |
| 119 | } catch ( TimeoutException $e ) { |
| 120 | throw $e; |
| 121 | } catch ( Exception $e ) { |
| 122 | $this->throwException( $e ); |
| 123 | } |
| 124 | |
| 125 | return $written; |
| 126 | } |
| 127 | |
| 128 | /** |
| 129 | * Throw away some of the data according to the sample rate. |
| 130 | * @param StatsdDataInterface[] $data |
| 131 | * @return StatsdDataInterface[] |
| 132 | * @throws LogicException |
| 133 | */ |
| 134 | protected function sampleData( $data ) { |
| 135 | $newData = []; |
| 136 | $mt_rand_max = mt_getrandmax(); |
| 137 | foreach ( $data as $item ) { |
| 138 | $samplingRate = $item->getSampleRate(); |
| 139 | if ( $samplingRate <= 0.0 || $samplingRate > 1.0 ) { |
| 140 | throw new LogicException( 'Sampling rate shall be within ]0, 1]' ); |
| 141 | } |
| 142 | if ( |
| 143 | $samplingRate === 1 || |
| 144 | ( mt_rand() / $mt_rand_max <= $samplingRate ) |
| 145 | ) { |
| 146 | $newData[] = $item; |
| 147 | } |
| 148 | } |
| 149 | return $newData; |
| 150 | } |
| 151 | |
| 152 | /** |
| 153 | * Ideally this would override parent::throwException(), but that is private, |
| 154 | * not protected. |
| 155 | * |
| 156 | * @param Exception $exception |
| 157 | */ |
| 158 | private function throwException( Exception $exception ) { |
| 159 | if ( !$this->getFailSilently() ) { |
| 160 | throw $exception; |
| 161 | } |
| 162 | } |
| 163 | } |