From: Antoine Musso <hashar@free.fr>
Date: Mon, 29 May 2017 21:58:33 +0000 (+0200)
Subject: Add WAN Cache to SiteStats::jobs
X-Git-Tag: 1.31.0-rc.0~2601^2
X-Git-Url: http://git.cyclocoop.org/%27%20.%20url_absolue%28%24favicon%29%20.%20?a=commitdiff_plain;h=29aaac5c631f8ed042cde9224d70fad00566073a;p=lhc%2Fweb%2Fwiklou.git

Add WAN Cache to SiteStats::jobs

The method hits the jobrunner backend to find out how many jobs are
enqueued in each of the JobQueue.  It is publicly available via the
MediaWiki API request:
    /w/api.php?action=query&meta=siteinfo&siprop=statistics

That is often used by bots when querying recent changes among other and
with fast bot cause useless queries toward the jobrunner backend.

Wrap SiteStats::jobs() with a WAN cache under key SiteStats:jobscount.
Drop SiteStats::$jobs private variable that was used for in process
cache. The WAN Cache does it for us via 'pcTTL'.

That is similar to SiteStats::numberingroup().
Set TTL to one minute, which should still give fresh enough results for
public uses.

Cover that behavior with a test.

When writing tests I noticed MediaWikiTestCase generates a few jobs due
to the creation of the UTPage page:

* HTMLCacheUpdateJob to refresh backlinks (eg: history)
* RecentChangesUpdateJob which happens randomly

Pass EDIT_SUPPRESS_RC to doEditContent to prevent the first and blindly
delete entries in the recentChangesUpdate jobqueue for the second.

Change-Id: I95a272d0691d779bfee9e7a671cbab66a113dfa1
---

diff --git a/includes/SiteStats.php b/includes/SiteStats.php
index 86a4f63aa4..90fd57bbce 100644
--- a/includes/SiteStats.php
+++ b/includes/SiteStats.php
@@ -34,9 +34,6 @@ class SiteStats {
 	/** @var bool */
 	private static $loaded = false;
 
-	/** @var int */
-	private static $jobs;
-
 	/** @var int[] */
 	private static $pageCount = [];
 
@@ -213,17 +210,24 @@ class SiteStats {
 	}
 
 	/**
+	 * Total number of jobs in the job queue.
 	 * @return int
 	 */
 	static function jobs() {
-		if ( !isset( self::$jobs ) ) {
-			try{
-				self::$jobs = array_sum( JobQueueGroup::singleton()->getQueueSizes() );
-			} catch ( JobQueueError $e ) {
-				self::$jobs = 0;
-			}
-		}
-		return self::$jobs;
+		$cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
+		return $cache->getWithSetCallback(
+			$cache->makeKey( 'SiteStats', 'jobscount' ),
+			$cache::TTL_MINUTE,
+			function ( $oldValue, &$ttl, array &$setOpts ) {
+				try{
+					$jobs = array_sum( JobQueueGroup::singleton()->getQueueSizes() );
+				} catch ( JobQueueError $e ) {
+					$jobs = 0;
+				}
+				return $jobs;
+			},
+			[ 'pcTTL' => $cache::TTL_PROC_LONG ]
+		);
 	}
 
 	/**
diff --git a/tests/phpunit/MediaWikiTestCase.php b/tests/phpunit/MediaWikiTestCase.php
index df3d5681d7..0e920da520 100644
--- a/tests/phpunit/MediaWikiTestCase.php
+++ b/tests/phpunit/MediaWikiTestCase.php
@@ -1073,10 +1073,15 @@ abstract class MediaWikiTestCase extends PHPUnit_Framework_TestCase {
 			$page->doEditContent(
 				new WikitextContent( 'UTContent' ),
 				'UTPageSummary',
-				EDIT_NEW,
+				EDIT_NEW | EDIT_SUPPRESS_RC,
 				false,
 				$user
 			);
+			// an edit always attempt to purge backlink links such as history
+			// pages. That is unneccessary.
+			JobQueueGroup::singleton()->get( 'htmlCacheUpdate' )->delete();
+			// WikiPages::doEditUpdates randomly adds RC purges
+			JobQueueGroup::singleton()->get( 'recentChangesUpdate' )->delete();
 
 			// doEditContent() probably started the session via
 			// User::loadFromSession(). Close it now.
diff --git a/tests/phpunit/includes/SiteStatsTest.php b/tests/phpunit/includes/SiteStatsTest.php
new file mode 100644
index 0000000000..ea476a7cfa
--- /dev/null
+++ b/tests/phpunit/includes/SiteStatsTest.php
@@ -0,0 +1,36 @@
+<?php
+
+class SiteStatsTest extends MediaWikiTestCase {
+
+	/**
+	 * @covers SiteStats::jobs
+	 */
+	function testJobsCountGetCached() {
+		$this->setService( 'MainWANObjectCache',
+			new WANObjectCache( [ 'cache' => new HashBagOStuff() ] ) );
+		$cache = \MediaWiki\MediaWikiServices::getInstance()->getMainWANObjectCache();
+		$jobq = JobQueueGroup::singleton();
+
+		$jobq->push( new NullJob( Title::newMainPage(), [] ) );
+		$this->assertEquals( 1, SiteStats::jobs(),
+			 'A single job enqueued bumps jobscount stat to 1' );
+
+		$jobq->push( new NullJob( Title::newMainPage(), [] ) );
+		$this->assertEquals( 1, SiteStats::jobs(),
+			'SiteStats::jobs() count does not reflect addition ' .
+			'of a second job (cached)'
+		);
+
+		$jobq->get( 'null' )->delete();  // clear jobqueue
+		$this->assertEquals( 0, $jobq->get( 'null' )->getSize(),
+			'Job queue for NullJob has been cleaned' );
+
+		$cache->delete( $cache->makeKey( 'SiteStats', 'jobscount' ) );
+		$this->assertEquals( 1, SiteStats::jobs(),
+			'jobs count is kept in process cache' );
+
+		$cache->clearProcessCache();
+		$this->assertEquals( 0, SiteStats::jobs() );
+	}
+
+}