From d7f2ed07de8684cf9e9c5a9dc9a168b48ba74ccd Mon Sep 17 00:00:00 2001
From: Nivanka Fonseka <nivanka@silverstripers.com>
Date: Tue, 9 Nov 2021 15:56:55 +1300
Subject: [PATCH] added Queued Cron Task to define a priority order for the
 cron tasks

---
 src/Controllers/CronTaskController.php | 24 ++++++++++++++++++++----
 src/Interfaces/QueuedCronTask.php      | 18 ++++++++++++++++++
 2 files changed, 38 insertions(+), 4 deletions(-)
 create mode 100644 src/Interfaces/QueuedCronTask.php

diff --git a/src/Controllers/CronTaskController.php b/src/Controllers/CronTaskController.php
index d3c2985..952d768 100644
--- a/src/Controllers/CronTaskController.php
+++ b/src/Controllers/CronTaskController.php
@@ -13,6 +13,7 @@
 use SilverStripe\Core\Injector\Injector;
 use SilverStripe\CronTask\CronTaskStatus;
 use SilverStripe\CronTask\Interfaces\CronTask;
+use SilverStripe\CronTask\Interfaces\QueuedCronTask;
 use SilverStripe\ORM\FieldType\DBDatetime;
 use SilverStripe\Security\Permission;
 use SilverStripe\Security\Security;
@@ -129,18 +130,33 @@ public function index(HTTPRequest $request)
         $isDebug = (bool)$request->getVar('debug');
 
         // Check each task
-        $tasks = ClassInfo::implementorsOf(CronTask::class);
+        $tasks = array_merge(
+            ClassInfo::implementorsOf(CronTask::class),
+            ClassInfo::implementorsOf(QueuedCronTask::class),
+        );
         if (empty($tasks)) {
             $this->output("There are no implementators of CronTask to run", 2);
             return;
         }
+
+        $jobs = [];
         foreach ($tasks as $subclass) {
-            $task = Injector::inst()->create($subclass);
+            $jobs[] = Injector::inst()->create($subclass);
+        }
+
+        usort($jobs, function ($a, $b) {
+            $priorityA = method_exists($a, 'priority') ? $a->priority() : 0;
+            $priorityB = method_exists($b, 'priority') ? $b->priority() : 0;
+            return $priorityA > $priorityB ? -1 : 1;
+        });
+
+        foreach ($jobs as $job) {
             // falsey schedule = don't run task
-            if ($task->getSchedule()) {
-                $this->runTask($task, $isDebug);
+            if ($job->getSchedule()) {
+                $this->runTask($job, $isDebug);
             }
         }
+
     }
 
     /**
diff --git a/src/Interfaces/QueuedCronTask.php b/src/Interfaces/QueuedCronTask.php
new file mode 100644
index 0000000..c8a4671
--- /dev/null
+++ b/src/Interfaces/QueuedCronTask.php
@@ -0,0 +1,18 @@
+<?php
+
+
+namespace SilverStripe\CronTask\Interfaces;
+
+
+interface QueuedCronTask extends CronTask
+{
+
+    /**
+     * Specify the priority of this job.
+     * priority().
+     *
+     * @return int
+     */
+    public function priority();
+
+}