Add an External Grader Problem in Studio

Tags: educator how-to

To create a code response problem in Studio, follow these steps.

1. In the unit where you want to add the code response problem, select Problem under Add New Component.

2. In the list that opens, select the Advanced tab, and then select Blank Advanced Problem. The advanced editor opens.

3. In the new component, select Edit.

4. In the problem editor, enter the online learning XML (OLX) definition for the problem that you created.

5. Select Save.

6. Test the problem in the LMS.

Note

To validate your external grader and test a problem, you must view the component in a published unit in the LMS. If you test a problem in Studio, you receive an “Error: No grader has been set up for this problem” message.

OLX Definition

To create an external grader problem in Studio, you create an Open Learning XML (OLX) definition of the problem, and then add the code to a problem component.

Note

Your site operations team will need to first Enable and Test Event Bus–Based XQueue Submissions, and then give you the queuename to use in your problem.

The OLX definition of a problem contains the following information.

• A queuename attribute that specifies the name of the XQueue that your site operations team created.

• A <label> element that contains the instructions for the problem.

• The type of input that the problem accepts, specified as one of two elements.

  • <textbox>: The learner enters code in a browser field while the learner views the course unit.

  • <filesubmission>: The learner attaches and submits a code file in the unit.

• (optional) An element that contains a JSON object that you send to the external grader. For example, you can use the <grader_payload> element to tell the grader which tests to run for a problem.

The following example shows the OLX definition of a problem that uses an external grader.

<problem>
  <coderesponse queuename="my_course_queue">
    <label>Write a program that prints "hello world".</label>
    <textbox rows="10" cols="80" mode="python" tabsize="4"/>
    <codeparam>
      <initial_display>
        # students write your program here
        print ""
      </initial_display>
      <answer_display>
        print "hello world"
      </answer_display>
      <grader_payload>
        {"output": "hello world", "max_length": 2}
      </grader_payload>
    </codeparam>
  </coderesponse>
</problem>

Testing the Grader

You must test the grader thoroughly, via the LMS interface, before your course starts. Be sure to test incorrect code as well as correct code to ensure that the grader responds with appropriate scores and messages.

If you know the grader will be unavailable at a certain time for maintenance, you might consider adding a course update.

See also

About External Grader Problems (concept)

Enable and Test Event Bus–Based XQueue Submissions (site operators how-to)

Maintenance chart

Review Date	Working Group Reviewer	Release	Test situation
07/03/2025	Leira (Curricu.me)	Sumac	Pass

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