/** @var string All workers with the same key share the lock */
protected $key;
- /** @var int Maximum number of workers doing the task simultaneously */
+ /** @var int Maximum number of workers working on tasks with the same key simultaneously */
protected $workers;
+ /**
+ * Maximum number of workers working on this task type, regardless of key.
+ * 0 means unlimited. Max allowed value is 65536.
+ * The way the slot limit is enforced is overzealous - this option should be used with caution.
+ * @var int
+ */
+ protected $slots = 0;
/** @var int If this number of workers are already working/waiting, fail instead of wait */
protected $maxqueue;
/** @var float Maximum time in seconds to wait for the lock */
* @param string $key
*/
protected function __construct( $conf, $type, $key ) {
- $this->key = $key;
$this->workers = $conf['workers'];
$this->maxqueue = $conf['maxqueue'];
$this->timeout = $conf['timeout'];
+ if ( isset( $conf['slots'] ) ) {
+ $this->slots = $conf['slots'];
+ }
+
+ if ( $this->slots ) {
+ $key = $this->hashKeyIntoSlots( $key, $this->slots );
+ }
+ $this->key = $key;
}
/**
* @return Status value is one of Released/NotLocked/Error
*/
abstract public function release();
+
+ /**
+ * Given a key (any string) and the number of lots, returns a slot number (an integer from the [0..($slots-1)] range).
+ * This is used for a global limit on the number of instances of a given type that can acquire a lock.
+ * The hashing is deterministic so that PoolCounter::$workers is always an upper limit of how many instances with
+ * the same key can acquire a lock.
+ *
+ * @param string $key PoolCounter instance key (any string)
+ * @param int $slots the number of slots (max allowed value is 65536)
+ * @return int
+ */
+ protected function hashKeyIntoSlots( $key, $slots ) {
+ return hexdec( substr( sha1( $key ), 0, 4 ) ) % $slots;
+ }
}
// @codingStandardsIgnoreStart Squiz.Classes.ValidClassName.NotCamelCaps
--- /dev/null
+<?php
+
+// We will use this class with getMockForAbstractClass to create a concrete mock class. That call will die if the
+// contructor is not public, unless we use disableOriginalConstructor(), in which case we could not test the constructor.
+abstract class PoolCounterAbstractMock extends PoolCounter {
+ public function __construct() {
+ call_user_func_array( 'parent::__construct', func_get_args() );
+ }
+}
+
+class PoolCounterTest extends MediaWikiTestCase {
+ public function testConstruct() {
+ $poolCounterConfig = array(
+ 'class' => 'PoolCounterMock',
+ 'timeout' => 10,
+ 'workers' => 10,
+ 'maxqueue' => 100,
+ );
+
+ $poolCounter = $this->getMockBuilder( 'PoolCounterAbstractMock' )
+ ->setConstructorArgs( array( $poolCounterConfig, 'testCounter', 'someKey' ) )
+ // don't mock anything - the proper syntax would be setMethods(null), but due to a PHPUnit bug that
+ // does not work with getMockForAbstractClass()
+ ->setMethods( array( 'idontexist' ) )
+ ->getMockForAbstractClass();
+ $this->assertInstanceOf( 'PoolCounter', $poolCounter );
+ }
+
+ public function testConstructWithSlots() {
+ $poolCounterConfig = array(
+ 'class' => 'PoolCounterMock',
+ 'timeout' => 10,
+ 'workers' => 10,
+ 'slots' => 2,
+ 'maxqueue' => 100,
+ );
+
+ $poolCounter = $this->getMockBuilder( 'PoolCounterAbstractMock' )
+ ->setConstructorArgs( array( $poolCounterConfig, 'testCounter', 'key' ) )
+ ->setMethods( array( 'idontexist' ) ) // don't mock anything
+ ->getMockForAbstractClass();
+ $this->assertInstanceOf( 'PoolCounter', $poolCounter );
+ }
+
+ public function testHashKeyIntoSlots() {
+ $poolCounter = $this->getMockBuilder( 'PoolCounterAbstractMock' )
+ // don't mock anything - the proper syntax would be setMethods(null), but due to a PHPUnit bug that
+ // does not work with getMockForAbstractClass()
+ ->setMethods( array( 'idontexist' ) )
+ ->disableOriginalConstructor()
+ ->getMockForAbstractClass();
+
+ $hashKeyIntoSlots = new ReflectionMethod($poolCounter, 'hashKeyIntoSlots' );
+ $hashKeyIntoSlots->setAccessible( true );
+
+
+ $keysWithTwoSlots = $keysWithFiveSlots = array();
+ foreach ( range( 1, 100 ) as $i ) {
+ $keysWithTwoSlots[] = $hashKeyIntoSlots->invoke( $poolCounter, 'key ' . $i, 2 );
+ $keysWithFiveSlots[] = $hashKeyIntoSlots->invoke( $poolCounter, 'key ' . $i, 5 );
+ }
+
+ $this->assertArrayEquals( range( 0, 1 ), array_unique( $keysWithTwoSlots ) );
+ $this->assertArrayEquals( range( 0, 4 ), array_unique( $keysWithFiveSlots ) );
+
+ // make sure it is deterministic
+ $this->assertEquals(
+ $hashKeyIntoSlots->invoke( $poolCounter, 'asdfgh', 1000 ),
+ $hashKeyIntoSlots->invoke( $poolCounter, 'asdfgh', 1000 )
+ );
+ }
+}