objectcache: add some WAN cache preemptive refresh tests

Added some extra sanity checks to WANObjectCache

Change-Id: Iac511b0cc1fc8d57ac98e9d7f2cacbcddc1c6db9

diff --git a/includes/libs/objectcache/WANObjectCache.php b/includes/libs/objectcache/WANObjectCache.php
index a3c9d71..e63b32e 100644 (file)
--- a/includes/libs/objectcache/WANObjectCache.php
+++ b/includes/libs/objectcache/WANObjectCache.php
@@ -207,7 +207,7 @@ class WANObjectCache implements IExpiringStore, LoggerAwareInterface {
         * @return WANObjectCache
         */
        public static function newEmpty() {
-               return new self( [
+               return new static( [
                        'cache'   => new EmptyBagOStuff(),
                        'pool'    => 'empty'
                ] );
@@ -314,7 +314,7 @@ class WANObjectCache implements IExpiringStore, LoggerAwareInterface {
                        $wrappedValues += $this->cache->getMulti( $keysGet );
                }
                // Time used to compare/init "check" keys (derived after getMulti() to be pessimistic)
-               $now = microtime( true );
+               $now = $this->getCurrentTime();
 
                // Collect timestamps from all "check" keys
                $purgeValuesForAll = $this->processCheckKeys( $checkKeysForAll, $wrappedValues, $now );
@@ -443,7 +443,7 @@ class WANObjectCache implements IExpiringStore, LoggerAwareInterface {
         * @return bool Success
         */
        final public function set( $key, $value, $ttl = 0, array $opts = [] ) {
-               $now = microtime( true );
+               $now = $this->getCurrentTime();
                $lockTSE = isset( $opts['lockTSE'] ) ? $opts['lockTSE'] : self::TSE_NONE;
                $staleTTL = isset( $opts['staleTTL'] ) ? $opts['staleTTL'] : self::STALE_TTL_NONE;
                $age = isset( $opts['since'] ) ? max( 0, $now - $opts['since'] ) : 0;
@@ -594,7 +594,7 @@ class WANObjectCache implements IExpiringStore, LoggerAwareInterface {
                        $time = $purge[self::FLD_TIME];
                } else {
                        // Casting assures identical floats for the next getCheckKeyTime() calls
-                       $now = (string)microtime( true );
+                       $now = (string)$this->getCurrentTime();
                        $this->cache->add( $key,
                                $this->makePurgeValue( $now, self::HOLDOFF_TTL ),
                                self::CHECK_KEY_TTL
@@ -972,7 +972,7 @@ class WANObjectCache implements IExpiringStore, LoggerAwareInterface {
                $cValue = $this->get( $key, $curTTL, $checkKeys, $asOf ); // current value
                $value = $cValue; // return value
 
-               $preCallbackTime = microtime( true );
+               $preCallbackTime = $this->getCurrentTime();
                // Determine if a cached value regeneration is needed or desired
                if ( $value !== false
                        && $curTTL > 0
@@ -1048,7 +1048,7 @@ class WANObjectCache implements IExpiringStore, LoggerAwareInterface {
                // so use a special INTERIM key to pass the new value around threads.
                if ( ( $isTombstone && $lockTSE > 0 ) && $valueIsCacheable ) {
                        $tempTTL = max( 1, (int)$lockTSE ); // set() expects seconds
-                       $newAsOf = microtime( true );
+                       $newAsOf = $this->getCurrentTime();
                        $wrapped = $this->wrap( $value, $tempTTL, $newAsOf );
                        // Avoid using set() to avoid pointless mcrouter broadcasting
                        $this->setInterimValue( $key, $wrapped, $tempTTL );
@@ -1081,7 +1081,7 @@ class WANObjectCache implements IExpiringStore, LoggerAwareInterface {
         */
        protected function getInterimValue( $key, $versioned, $minTime, &$asOf ) {
                $wrapped = $this->cache->get( self::INTERIM_KEY_PREFIX . $key );
-               list( $value ) = $this->unwrap( $wrapped, microtime( true ) );
+               list( $value ) = $this->unwrap( $wrapped, $this->getCurrentTime() );
                if ( $value !== false && $this->isValid( $value, $versioned, $asOf, $minTime ) ) {
                        $asOf = $wrapped[self::FLD_TIME];
 
@@ -1539,7 +1539,7 @@ class WANObjectCache implements IExpiringStore, LoggerAwareInterface {
                if ( $this->purgeRelayer instanceof EventRelayerNull ) {
                        // This handles the mcrouter and the single-DC case
                        $ok = $this->cache->set( $key,
-                               $this->makePurgeValue( microtime( true ), self::HOLDOFF_NONE ),
+                               $this->makePurgeValue( $this->getCurrentTime(), self::HOLDOFF_NONE ),
                                $ttl
                        );
                } else {
@@ -1598,7 +1598,9 @@ class WANObjectCache implements IExpiringStore, LoggerAwareInterface {
         * @return bool
         */
        protected function worthRefreshExpiring( $curTTL, $lowTTL ) {
-               if ( $curTTL >= $lowTTL ) {
+               if ( $lowTTL <= 0 ) {
+                       return false;
+               } elseif ( $curTTL >= $lowTTL ) {
                        return false;
                } elseif ( $curTTL <= 0 ) {
                        return true;
@@ -1625,6 +1627,10 @@ class WANObjectCache implements IExpiringStore, LoggerAwareInterface {
         * @return bool
         */
        protected function worthRefreshPopular( $asOf, $ageNew, $timeTillRefresh, $now ) {
+               if ( $ageNew < 0 || $timeTillRefresh <= 0 ) {
+                       return false;
+               }
+
                $age = $now - $asOf;
                $timeOld = $age - $ageNew;
                if ( $timeOld <= 0 ) {
@@ -1746,6 +1752,14 @@ class WANObjectCache implements IExpiringStore, LoggerAwareInterface {
                return isset( $parts[1] ) ? $parts[1] : $parts[0]; // sanity
        }
 
+       /**
+        * @return float UNIX timestamp
+        * @codeCoverageIgnore
+        */
+       protected function getCurrentTime() {
+               return microtime( true );
+       }
+
        /**
         * @param string $value Wrapped value like "PURGED:<timestamp>:<holdoff>"
         * @return array|bool Array containing a UNIX timestamp (float) and holdoff period (integer),

diff --git a/tests/phpunit/includes/libs/objectcache/WANObjectCacheTest.php b/tests/phpunit/includes/libs/objectcache/WANObjectCacheTest.php
index 934d49a..592f72a 100644 (file)
--- a/tests/phpunit/includes/libs/objectcache/WANObjectCacheTest.php
+++ b/tests/phpunit/includes/libs/objectcache/WANObjectCacheTest.php
@@ -275,6 +275,66 @@ class WANObjectCacheTest extends PHPUnit_Framework_TestCase {
                ];
        }
 
+       public function testPreemtiveRefresh() {
+               $value = 'KatCafe';
+               $wasSet = 0;
+               $func = function ( $old, &$ttl, &$opts, $asOf ) use ( &$wasSet, $value )
+               {
+                       ++$wasSet;
+                       return $value;
+               };
+
+               $cache = new NearExpiringWANObjectCache( [
+                       'cache'   => new HashBagOStuff(),
+                       'pool'    => 'empty'
+               ] );
+
+               $wasSet = 0;
+               $key = wfRandomString();
+               $opts = [ 'lowTTL' => 30 ];
+               $v = $cache->getWithSetCallback( $key, 20, $func, $opts );
+               $this->assertEquals( $value, $v, "Value returned" );
+               $this->assertEquals( 1, $wasSet, "Value calculated" );
+               $v = $cache->getWithSetCallback( $key, 20, $func, $opts );
+               $this->assertEquals( 2, $wasSet, "Value re-calculated" );
+
+               $wasSet = 0;
+               $key = wfRandomString();
+               $opts = [ 'lowTTL' => 1 ];
+               $v = $cache->getWithSetCallback( $key, 30, $func, $opts );
+               $this->assertEquals( $value, $v, "Value returned" );
+               $this->assertEquals( 1, $wasSet, "Value calculated" );
+               $v = $cache->getWithSetCallback( $key, 30, $func, $opts );
+               $this->assertEquals( 1, $wasSet, "Value cached" );
+
+               $cache = new PopularityRefreshingWANObjectCache( [
+                       'cache'   => new HashBagOStuff(),
+                       'pool'    => 'empty'
+               ] );
+
+               $now = microtime( true ); // reference time
+               $wasSet = 0;
+               $key = wfRandomString();
+               $opts = [ 'hotTTR' => 900 ];
+               $v = $cache->getWithSetCallback( $key, 60, $func, $opts );
+               $this->assertEquals( $value, $v, "Value returned" );
+               $this->assertEquals( 1, $wasSet, "Value calculated" );
+               $cache->setTime( $now + 30 );
+               $v = $cache->getWithSetCallback( $key, 60, $func, $opts );
+               $this->assertEquals( 1, $wasSet, "Value cached" );
+
+               $wasSet = 0;
+               $key = wfRandomString();
+               $opts = [ 'hotTTR' => 10 ];
+               $cache->setTime( $now );
+               $v = $cache->getWithSetCallback( $key, 60, $func, $opts );
+               $this->assertEquals( $value, $v, "Value returned" );
+               $this->assertEquals( 1, $wasSet, "Value calculated" );
+               $cache->setTime( $now + 30 );
+               $v = $cache->getWithSetCallback( $key, 60, $func, $opts );
+               $this->assertEquals( 2, $wasSet, "Value re-calculated" );
+       }
+
        /**
         * @covers WANObjectCache::getWithSetCallback()
         * @covers WANObjectCache::doGetWithSetCallback()
@@ -1346,3 +1406,44 @@ class WANObjectCacheTest extends PHPUnit_Framework_TestCase {
                $this->assertEquals( $class, $wanCache->determineKeyClass( $key ) );
        }
 }
+
+class TimeAdjustableHashBagOStuff extends HashBagOStuff {
+       private $timeOverride = 0;
+
+       public function setTime( $time ) {
+               $this->timeOverride = $time;
+       }
+
+       protected function getCurrentTime() {
+               return $this->timeOverride ?: parent::getCurrentTime();
+       }
+}
+
+class TimeAdjustableWANObjectCache extends WANObjectCache {
+       private $timeOverride = 0;
+
+       public function setTime( $time ) {
+               $this->timeOverride = $time;
+               if ( $this->cache instanceof TimeAdjustableHashBagOStuff ) {
+                       $this->cache->setTime( $time );
+               }
+       }
+
+       protected function getCurrentTime() {
+               return $this->timeOverride ?: parent::getCurrentTime();
+       }
+}
+
+class NearExpiringWANObjectCache extends TimeAdjustableWANObjectCache {
+       const CLOCK_SKEW = 1;
+
+       protected function worthRefreshExpiring( $curTTL, $lowTTL ) {
+               return ( ( $curTTL + self::CLOCK_SKEW ) < $lowTTL );
+       }
+}
+
+class PopularityRefreshingWANObjectCache extends TimeAdjustableWANObjectCache {
+       protected function worthRefreshPopular( $asOf, $ageNew, $timeTillRefresh, $now ) {
+               return ( ( $now - $asOf ) > $timeTillRefresh );
+       }
+}