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Make statsd sampling rates configurable

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Change-Id: I6f5b0531ff5caf4b0fda38331fabad93a6a8a360
This commit is contained in:
Gergő Tisza 2016-04-12 22:08:20 +00:00
parent 8e7a0a0912
commit b203ec5fcd
4 changed files with 63 additions and 13 deletions
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8
includes/DefaultSettings.php
View file

@ -5901,6 +5901,14 @@ $wgStatsdServer = false;
*/
$wgStatsdMetricPrefix = 'MediaWiki';
/**
* Sampling rate for statsd metrics 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).
* @since 1.28
*/
$wgStatsdSamplingRates = [];
/**
* InfoAction retrieves a list of transclusion links (both to and from).
* This number puts a limit on that query in the case of highly transcluded

1
includes/GlobalFunctions.php
View file

@ -1182,6 +1182,7 @@ function wfLogProfilingData() {
$statsdPort = isset( $statsdServer[1] ) ? $statsdServer[1] : 8125;
$statsdSender = new SocketSender( $statsdHost, $statsdPort );
$statsdClient = new SamplingStatsdClient( $statsdSender, true, false );
$statsdClient->setSamplingRates( $config->get( 'StatsdSamplingRates' ) );
$statsdClient->send( $context->getStats()->getBuffer() );
} catch ( Exception $ex ) {
MWExceptionHandler::logException( $ex );

32
includes/libs/SamplingStatsdClient.php
View file

@ -30,6 +30,19 @@ use Liuggio\StatsdClient\Entity\StatsdDataInterface;
* @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.
@ -37,11 +50,18 @@ class SamplingStatsdClient extends StatsdClient {
* {@inheritDoc}
*/
public function appendSampleRate( $data, $sampleRate = 1 ) {
if ( $sampleRate < 1 ) {
array_walk( $data, function( $item ) use ( $sampleRate ) {
$samplingRates = $this->samplingRates;
if ( !$samplingRates && $sampleRate !== 1 ) {
$samplingRates = [ '*' => $sampleRate ];
}
if ( $samplingRates ) {
array_walk( $data, function( $item ) use ( $samplingRates ) {
/** @var $item StatsdData */
if ( $item->getSampleRate() === 1 ) {
$item->setSampleRate( $sampleRate );
foreach ( $samplingRates as $pattern => $rate ) {
if ( fnmatch( $pattern, $item->getKey(), FNM_NOESCAPE ) ) {
$item->setSampleRate( $item->getSampleRate() * $rate );
break;
}
}
} );
}
@ -74,9 +94,7 @@ class SamplingStatsdClient extends StatsdClient {
}
// add sampling
if ( $sampleRate < 1 ) {
$data = $this->appendSampleRate( $data, $sampleRate );
}
$data = $this->appendSampleRate( $data, $sampleRate );
$data = $this->sampleData( $data );
$data = array_map( 'strval', $data );

35
tests/phpunit/includes/libs/SamplingStatsdClientTest.php
View file

@ -32,12 +32,35 @@ class SamplingStatsdClientTest extends PHPUnit_Framework_TestCase {
return [
// $data, $sampleRate, $seed, $expectWrite
[ $unsampled, 1, 0 /*0.44*/, $unsampled ],
[ $sampled, 1, 0 /*0.44*/, null ],
[ $sampled, 1, 4 /*0.03*/, $sampled ],
[ $unsampled, 0.1, 4 /*0.03*/, $sampled ],
[ $sampled, 0.5, 0 /*0.44*/, null ],
[ $sampled, 0.5, 4 /*0.03*/, $sampled ],
[ $unsampled, 1, 0 /*0.44*/, true ],
[ $sampled, 1, 0 /*0.44*/, false ],
[ $sampled, 1, 4 /*0.03*/, true ],
[ $unsampled, 0.1, 0 /*0.44*/, false ],
[ $sampled, 0.5, 0 /*0.44*/, false ],
[ $sampled, 0.5, 4 /*0.03*/, false ],
];
}
public function testSetSamplingRates() {
$matching = new StatsdData();
$matching->setKey( 'foo.bar' );
$matching->setValue( 1 );
$nonMatching = new StatsdData();
$nonMatching->setKey( 'oof.bar' );
$nonMatching->setValue( 1 );
$sender = $this->getMock( 'Liuggio\StatsdClient\Sender\SenderInterface' );
$sender->expects( $this->any() )->method( 'open' )->will( $this->returnValue( true ) );
$sender->expects( $this->once() )->method( 'write' )->with( $this->anything(),
$this->equalTo( $nonMatching ) );
$client = new SamplingStatsdClient( $sender );
$client->setSamplingRates( [ 'foo.*' => 0.2 ] );
mt_srand( 0 ); // next random is 0.44
$client->send( $matching );
mt_srand( 0 );
$client->send( $nonMatching );
}
}