[JobQueue] Cleaned up handling of orders a bit.

Change-Id: I83d060e0db97d5bebf042041b0bd20563b093418

diff --git a/includes/job/JobQueue.php b/includes/job/JobQueue.php
index 8ade0d5..641a61d 100644 (file)
--- a/includes/job/JobQueue.php
+++ b/includes/job/JobQueue.php
@@ -43,9 +43,16 @@ abstract class JobQueue {
        protected function __construct( array $params ) {
                $this->wiki = $params['wiki'];
                $this->type = $params['type'];
-               $this->order = isset( $params['order'] ) ? $params['order'] : 'random';
                $this->claimTTL = isset( $params['claimTTL'] ) ? $params['claimTTL'] : 0;
                $this->maxTries = isset( $params['maxTries'] ) ? $params['maxTries'] : 3;
+               if ( isset( $params['order'] ) && $params['order'] !== 'any' ) {
+                       $this->order = $params['order'];
+               } else {
+                       $this->order = $this->optimalOrder();
+               }
+               if ( !in_array( $this->order, $this->supportedOrders() ) ) {
+                       throw new MWException( __CLASS__ . " does not support '{$this->order}' order." );
+               }
        }
 
        /**
@@ -60,10 +67,10 @@ abstract class JobQueue {
         *                job runners since jobs can take different times to finish once popped.
         *                If "timestamp" is used, the queue will at least be loosely ordered
         *                by timestamp, allowing for some jobs to be popped off out of order.
-        *                If "random" is used, pop() will pick jobs in random order. This might be
-        *                useful for improving concurrency depending on the queue storage medium.
-        *                Note that "random" really means "don't care", so it may actually be FIFO
-        *                or only weakly random (e.g. pop() takes one of the first X jobs randomly).
+        *                If "random" is used, pop() will pick jobs in random order.
+        *                Note that it may only be weakly random (e.g. a lottery of the oldest X).
+        *                If "any" is choosen, the queue will use whatever order is the fastest.
+        *                This might be useful for improving concurrency for job acquisition.
         *   - claimTTL : If supported, the queue will recycle jobs that have been popped
         *                but not acknowledged as completed after this many seconds. Recycling
         *                of jobs simple means re-inserting them into the queue. Jobs can be
@@ -101,6 +108,23 @@ abstract class JobQueue {
                return $this->type;
        }
 
+       /**
+        * @return string One of (random, timestamp, fifo)
+        */
+       final public function getOrder() {
+               return $this->order;
+       }
+
+       /**
+        * @return Array Subset of (random, timestamp, fifo)
+        */
+       abstract public function supportedOrders();
+
+       /**
+        * @return string One of (random, timestamp, fifo)
+        */
+       abstract protected function optimalOrder();
+
        /**
         * Quickly check if the queue is empty (has no available jobs).
         * Queue classes should use caching if they are any slower without memcached.

diff --git a/includes/job/JobQueueDB.php b/includes/job/JobQueueDB.php
index ada0ac4..eb01c3e 100644 (file)
--- a/includes/job/JobQueueDB.php
+++ b/includes/job/JobQueueDB.php
@@ -50,6 +50,14 @@ class JobQueueDB extends JobQueue {
                $this->cluster = isset( $params['cluster'] ) ? $params['cluster'] : false;
        }
 
+       public function supportedOrders() {
+               return array( 'random', 'timestamp', 'fifo' );
+       }
+
+       protected function optimalOrder() {
+               return 'random';
+       }
+
        /**
         * @see JobQueue::doIsEmpty()
         * @return bool

diff --git a/includes/job/JobQueueRedis.php b/includes/job/JobQueueRedis.php
index 7dc9900..8e7588e 100644 (file)
--- a/includes/job/JobQueueRedis.php
+++ b/includes/job/JobQueueRedis.php
@@ -52,6 +52,14 @@ class JobQueueRedis extends JobQueue {
                $this->redisPool = RedisConnectionPool::singleton( $params['redisConfig'] );
        }
 
+       public function supportedOrders() {
+               return array( 'timestamp', 'fifo' );
+       }
+
+       protected function optimalOrder() {
+               return 'fifo';
+       }
+
        /**
         * @see JobQueue::doIsEmpty()
         * @return bool