commit cb398764c09982191a7139bbc681a4ad9a3be679
Author: darthsteven <darthsteven@99644.no-reply.drupal.org>
Date:   Thu Dec 1 20:50:54 2016 +0100

    Issue #1895580 by Steven Jones: Task priorities

diff --git a/hosting.api.php b/hosting.api.php
index 97008f4..31fc154 100644
--- a/hosting.api.php
+++ b/hosting.api.php
@@ -357,7 +357,7 @@ function hosting_QUEUE_TYPE_queue($count = 5) {
   global $provision_errors;
 
   drush_log(dt("Running tasks queue"));
-  $tasks = _hosting_get_new_tasks($count);
+  $tasks = hosting_get_new_tasks($count);
   foreach ($tasks as $task) {
     drush_invoke_process('@self', "hosting-task", array($task->nid), array(), array('fork' => TRUE));
   }
diff --git a/queued/hosting_queued.drush.inc b/queued/hosting_queued.drush.inc
index 983c45f..faeb12a 100644
--- a/queued/hosting_queued.drush.inc
+++ b/queued/hosting_queued.drush.inc
@@ -73,7 +73,7 @@ function drush_hosting_queued() {
 
 
     // Get some tasks to run
-    if ($tasks = @_hosting_get_new_tasks()) {
+    if ($tasks = @hosting_get_new_tasks()) {
       if (lock_acquire('hosting_queue_tasks_running', HOSTING_QUEUE_LOCK_TIMEOUT)) {
         drush_log('Acquired lock on task queue.');
         foreach ($tasks as $task) {
diff --git a/task/hosting_task.api.php b/task/hosting_task.api.php
index fa34820..4233d13 100644
--- a/task/hosting_task.api.php
+++ b/task/hosting_task.api.php
@@ -103,6 +103,24 @@ function hosting_task_TASK_TYPE_form_validate($form, &$form_state) {
 
 }
 
+/**
+ * Alter the query that selects the next tasks to run.
+ *
+ * You may use this hook to prioritise one type of task over another, or to
+ * prefer one client over another etc.
+ *
+ * @see hosting_get_new_tasks
+ *
+ * @param QueryAlterableInterface $query
+ *   The structured query that will select the next tasks to run.
+ */
+function hook_query_hosting_get_new_tasks_alter(QueryAlterableInterface $query) {
+  // Change the sort ordering so that newer tasks are preferred to older ones.
+  $order_by = &$query->getOrderBy();
+  $order_by['n.changed'] = 'DESC';
+  $order_by['n.nid'] = 'DESC';
+}
+
 
 /**
  * @} End of "addtogroup hooks".
diff --git a/task/hosting_task.module b/task/hosting_task.module
index 598ae49..34e03d5 100644
--- a/task/hosting_task.module
+++ b/task/hosting_task.module
@@ -724,7 +724,7 @@ function hosting_tasks_queue($count = 20) {
   global $provision_errors;
 
   drush_log(dt("Running tasks queue"));
-  $tasks = _hosting_get_new_tasks($count);
+  $tasks = hosting_get_new_tasks($count);
   foreach ($tasks as $task) {
     drush_invoke_process('@self', "hosting-task", array($task->nid), array('strict' => FALSE), array('fork' => TRUE));
   }
@@ -1323,35 +1323,46 @@ function hosting_get_tasks($filter_by = NULL, $filter_value = NULL, $count = 5,
 }
 
 /**
- * Retrieve a list of outstanding tasks.
+ * Retrieve a list of outstanding, queued, tasks.
  *
  * @param int $limit
- *   The amount of items to return.
+ *   The maximum number of tasks to return.
  *
  * @return array
  *   An associative array containing task nodes, indexed by node id.
  */
-function _hosting_get_new_tasks($limit = 20) {
+function hosting_get_new_tasks($limit = 20) {
   $return = array();
-  $result = db_query_range("SELECT t.nid
-    FROM {hosting_task} t
-    INNER JOIN {node} n
-    ON t.vid = n.vid
-    WHERE t.task_status = :task_status
-    GROUP BY t.rid
-    ORDER BY n.changed, n.nid ASC",
-    0,
-    $limit,
-    array(
-      ':task_status' => HOSTING_TASK_QUEUED,
-    ));
-  foreach ($result as $node) {
+  $query = db_select('hosting_task', 't');
+  $query->innerJoin('node', 'n', 't.vid = n.vid');
+  $query
+    ->fields('t', array('nid'))
+    ->condition('t.task_status', HOSTING_TASK_QUEUED)
+    ->orderBy('n.changed')
+    ->orderBy('n.nid')
+    ->groupBy('t.rid')
+    ->range(0, $limit)
+    ->addTag('hosting_get_new_tasks');
+
+  foreach ($query->execute() as $node) {
     $return[$node->nid] = node_load($node->nid);
   }
   return $return;
 }
 
 /**
+ * Retrieve a list of outstanding, queued, tasks.
+ *
+ * @deprecated First deprecated in Hosting 3.9 because this function was made
+ * part of the public API, use hosting_get_new_tasks() instead.
+ *
+ * @see hosting_get_new_tasks
+ */
+function _hosting_get_new_tasks($limit = 20) {
+  return hosting_get_new_tasks($limit);
+}
+
+/**
  * @name Error status definitions
  * @{
  * Bitmask values used to generate the error code to return.