MDL-80684 core: Fail running tasks on shutdown

When you kill a process which is executing a task, it now marks it as failed.

lib/classes/task/manager.php

@@ -26,6 +26,7 @@ namespace core\task;
 
 use core\lock\lock;
 use core\lock\lock_factory;
+use core_shutdown_manager;
 
 define('CORE_TASK_TASKS_FILENAME', 'db/tasks.php');
 /**
@@ -49,6 +50,16 @@ class manager {
      */
     const ADHOC_TASK_QUEUE_MODE_FILLING = 1;
 
+    /**
+     * @var ?task_base $runningtask Used to tell what is the current running task in this process.
+     */
+    public static ?task_base $runningtask = null;
+
+    /**
+     * @var bool Used to tell if the manager's shutdown callback has been registered.
+     */
+    public static bool $registeredshutdownhandler = false;
+
     /**
      * @var array A cached queue of adhoc tasks
      */
@@ -1078,6 +1089,42 @@ class manager {
         return null;
     }
 
+    /**
+     * This function will fail the currently running task, if there is one.
+     */
+    public static function fail_running_task(): void {
+        $runningtask = self::$runningtask;
+
+        if ($runningtask === null) {
+            return;
+        }
+
+        if ($runningtask instanceof scheduled_task) {
+            self::scheduled_task_failed($runningtask);
+            return;
+        }
+
+        if ($runningtask instanceof adhoc_task) {
+            self::adhoc_task_failed($runningtask);
+            return;
+        }
+    }
+
+    /**
+     * This function set's the $runningtask variable and ensures that the shutdown handler is registered.
+     * @param task_base $task
+     */
+    private static function task_starting(task_base $task): void {
+        self::$runningtask = $task;
+
+        // Add \core\task\manager::fail_running_task to shutdown manager, so we can ensure running tasks fail on shutdown.
+        if (!self::$registeredshutdownhandler) {
+            core_shutdown_manager::register_function('\core\task\manager::fail_running_task');
+
+            self::$registeredshutdownhandler = true;
+        }
+    }
+
     /**
      * This function indicates that an adhoc task was not completed successfully and should be retried.
      *
@@ -1127,6 +1174,8 @@ class manager {
             $task->get_cron_lock()->release();
         }
         $task->get_lock()->release();
+
+        self::$runningtask = null;
     }
 
     /**
@@ -1152,6 +1201,8 @@ class manager {
 
         $record = self::record_from_adhoc_task($task);
         $DB->update_record('task_adhoc', $record);
+
+        self::task_starting($task);
     }
 
     /**
@@ -1177,6 +1228,8 @@ class manager {
             $task->get_cron_lock()->release();
         }
         $task->get_lock()->release();
+
+        self::$runningtask = null;
     }
 
     /**
@@ -1221,6 +1274,8 @@ class manager {
             $task->get_cron_lock()->release();
         }
         $task->get_lock()->release();
+
+        self::$runningtask = null;
     }
 
     /**
@@ -1266,6 +1321,8 @@ class manager {
         $record->hostname = $hostname;
         $record->pid = $pid;
         $DB->update_record('task_scheduled', $record);
+
+        self::task_starting($task);
     }
 
     /**
@@ -1300,6 +1357,8 @@ class manager {
             $task->get_cron_lock()->release();
         }
         $task->get_lock()->release();
+
+        self::$runningtask = null;
     }
 
     /**