@@ -65,12 +65,16 @@ In Pull mode, student submissions are collected in XQueue, where they remain unt
The external grader polls the XQueue through a RESTful interface at a regular interval. When the external grader receives a submission, it runs the tests on it, then pushes the response back to XQueue through the RESTful interface. XQueue then delivers the response to the edX Learning Management System.
For example code of an external grader that uses Pull mode, see the `Stanford-Online repository xqueue_pull_ref <https://github.com/Stanford-Online/xqueue_pull_ref>`_.
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Push Mode
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In Push mode, XQueue actively pushes student submissions to the external grader, which passively waits for the next submission to grade. When the external grader receives a submission, it runs the tests on it, then synchronously delivers the graded response back to the XQueue. XQueue then delivers the response to the edX Learning Management System.
For example code of an external grader that uses Push mode, see the `edX repository xserver <https://github.com/edx/xserver>`_.
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External Grader Workflow
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@@ -101,6 +105,10 @@ The XQueue Interface
The student submission sent from XQueue to the grader, and the response sent from the grader to XQueue, are JSON objects, as described below.
.. note:: XQueue does not send the the student ID to the external grader. Your grader cannot access student IDs or associate student IDs with submissions.
For the code for the XQueue interface, see the file `urls.py in the edX XQueue repository <https://github.com/edx/xqueue/blob/master/queue/urls.py>`_.
