PROBLEM

With workflow-Actions it can happen, a task-export is triggered twice. This leads to multiple OKAPI Export Workers running in parallel for the same task leading to corrupt exports due to parallel file-access (files being removed/locked)

SOLUTION
To prevent this, we check if there is already a running OKAPI Export-Worker for the current task in a OKAPI Export-Workers work() and If so, we terminate with adding an error to the task-log what went wrong. This strategy can also be added to the general export-worker to prevent two export-workers are working at the same time.

"FRONTEND"-TESTS

This feature can not really be frontend tested. To test:

• create a task on your local instance, ideally with several workfiles that are processed with OKAPI (html, office, ...), e.g. _nextcloud/Developer/test-data/BY-ISSUE/TRANSLATE-5706/multi-docx-en-de.zip
• trigger the export with the following code added to Translate5\MaintenanceCli\Command\DevelopmentDevCommand: t5 dev
• vary the sleep-time to mimic some scenarios

        $taskId = <YOUR-TASK-ID>;

        $task = new \editor_Models_Task();
        $task->load($taskId);

        $worker1 = new \editor_Models_Export_Worker();
        $worker1->initExport($task, false);
        $worker2 = new \editor_Models_Export_Worker();
        $worker2->initExport($task, false);

        $logger = \Zend_Registry::get('logger');
        $logger->warn('E9999', 'QUEUED DEV EXPORT', [
            'task' => $task,
        ]);


        $worker1->queue();
        sleep(2);
        $worker2->queue();