protected $stats;
/** @var bool Whether to use "interim" caching while keys are tombstoned */
protected $useInterimHoldOffCaching = true;
+ /** @var callable|null Function that takes a WAN cache callback and runs it later */
+ protected $asyncHandler;
/** @var int ERR_* constant for the "last error" registry */
protected $lastRelayError = self::ERR_NONE;
* - relayers : Map of (action => EventRelayer object). Actions include "purge".
* - logger : LoggerInterface object
* - stats : LoggerInterface object
+ * - asyncHandler : A function that takes a callback and runs it later. If supplied,
+ * whenever a preemptive refresh would be triggered in getWithSetCallback(), the
+ * current cache value is still used instead. However, the async-handler function
+ * receives a WAN cache callback that, when run, will execute the value generation
+ * callback supplied by the getWithSetCallback() caller. The result will be saved
+ * as normal. The handler is expected to call the WAN cache callback at an opportune
+ * time (e.g. HTTP post-send), though generally within a few 100ms. [optional]
*/
public function __construct( array $params ) {
$this->cache = $params['cache'];
: new EventRelayerNull( [] );
$this->setLogger( isset( $params['logger'] ) ? $params['logger'] : new NullLogger() );
$this->stats = isset( $params['stats'] ) ? $params['stats'] : new NullStatsdDataFactory();
+ $this->asyncHandler = isset( $params['asyncHandler'] ) ? $params['asyncHandler'] : null;
}
public function setLogger( LoggerInterface $logger ) {
if ( $value !== false
&& $this->isAliveOrInGracePeriod( $curTTL, $graceTTL )
&& $this->isValid( $value, $versioned, $asOf, $minTime )
- && !$this->worthRefreshExpiring( $curTTL, $lowTTL )
- && !$this->worthRefreshPopular( $asOf, $ageNew, $popWindow, $preCallbackTime )
) {
- $this->stats->increment( "wanobjectcache.$kClass.hit.good" );
+ $preemptiveRefresh = (
+ $this->worthRefreshExpiring( $curTTL, $lowTTL ) ||
+ $this->worthRefreshPopular( $asOf, $ageNew, $popWindow, $preCallbackTime )
+ );
- return $value;
+ if ( !$preemptiveRefresh ) {
+ $this->stats->increment( "wanobjectcache.$kClass.hit.good" );
+
+ return $value;
+ } elseif ( $this->asyncHandler ) {
+ // Update the cache value later, such during post-send of an HTTP request
+ $func = $this->asyncHandler;
+ $func( function () use ( $key, $ttl, $callback, $opts, $asOf ) {
+ $opts['minAsOf'] = INF; // force a refresh
+ $this->doGetWithSetCallback( $key, $ttl, $callback, $opts, $asOf );
+ } );
+ $this->stats->increment( "wanobjectcache.$kClass.hit.refresh" );
+
+ return $value;
+ }
}
// A deleted key with a negative TTL left must be tombstoned
public function testPreemtiveRefresh() {
$value = 'KatCafe';
$wasSet = 0;
- $func = function ( $old, &$ttl, &$opts, $asOf ) use ( &$wasSet, $value )
+ $func = function ( $old, &$ttl, &$opts, $asOf ) use ( &$wasSet, &$value )
{
++$wasSet;
return $value;
};
$cache = new NearExpiringWANObjectCache( [
- 'cache' => new HashBagOStuff(),
- 'pool' => 'empty'
+ 'cache' => new HashBagOStuff(),
+ 'pool' => 'empty',
] );
$wasSet = 0;
$v = $cache->getWithSetCallback( $key, 30, $func, $opts );
$this->assertEquals( 1, $wasSet, "Value cached" );
+ $asycList = [];
+ $asyncHandler = function ( $callback ) use ( &$asycList ) {
+ $asycList[] = $callback;
+ };
+ $cache = new NearExpiringWANObjectCache( [
+ 'cache' => new TimeAdjustableHashBagOStuff(),
+ 'pool' => 'empty',
+ 'asyncHandler' => $asyncHandler
+ ] );
+
+ $now = microtime( true ); // reference time
+ $cache->setTime( $now );
+
+ $wasSet = 0;
+ $key = wfRandomString();
+ $checkKey = wfRandomString();
+ $opts = [ 'lowTTL' => 100 ];
+ $v = $cache->getWithSetCallback( $key, 300, $func, $opts );
+ $this->assertEquals( $value, $v, "Value returned" );
+ $this->assertEquals( 1, $wasSet, "Value calculated" );
+ $v = $cache->getWithSetCallback( $key, 300, $func, $opts );
+ $this->assertEquals( 1, $wasSet, "Cached value used" );
+ $this->assertEquals( $v, $value, "Value cached" );
+
+ $cache->setTime( $now + 250 );
+ $v = $cache->getWithSetCallback( $key, 300, $func, $opts );
+ $this->assertEquals( $value, $v, "Value returned" );
+ $this->assertEquals( 1, $wasSet, "Stale value used" );
+ $this->assertEquals( 1, count( $asycList ), "Refresh deferred." );
+ $value = 'NewCatsInTown'; // change callback return value
+ $asycList[0](); // run the refresh callback
+ $asycList = [];
+ $this->assertEquals( 2, $wasSet, "Value calculated at later time" );
+ $this->assertEquals( 0, count( $asycList ), "No deferred refreshes added." );
+ $v = $cache->getWithSetCallback( $key, 300, $func, $opts );
+ $this->assertEquals( $value, $v, "New value stored" );
+
$cache = new PopularityRefreshingWANObjectCache( [
- 'cache' => new HashBagOStuff(),
+ 'cache' => new TimeAdjustableHashBagOStuff(),
'pool' => 'empty'
] );
- $now = microtime( true ); // reference time
+ $cache->setTime( $now );
+
$wasSet = 0;
$key = wfRandomString();
$opts = [ 'hotTTR' => 900 ];
$this->assertEquals( 1, $wasSet, "Value calculated" );
$cache->setTime( $now + 30 );
$v = $cache->getWithSetCallback( $key, 60, $func, $opts );
+ $this->assertEquals( $value, $v, "Value returned" );
$this->assertEquals( 2, $wasSet, "Value re-calculated" );
}