Use runtime-provided XQueueService instead of constructing it in ProblemBlock

[irtazaakram]

This PR updates ProblemBlock to request XQueueService via the XBlock runtime (self.runtime.service(self, "xqueue")) instead of directly constructing it inside the block and moves XQueueService from xmodule/capa/xqueue_interface.py to xmodule/services.py

This aligns with the standard service pattern and allows the Problem XBlock to live in xblocks-contrib/problem without copying the XQueueService implementation into that repo.

TESTING

OLX for sample question:

<problem>
  <coderesponse queuename="openedx">
    <label>Type "Hello World" in the box below.</label>
    <textbox rows="3" cols="80" mode="text" tabsize="4"/>
    <codeparam>
      <initial_display>Hello ...</initial_display>
      <grader_payload>{"check": "hello_match"}</grader_payload>
    </codeparam>
  </coderesponse>
  <solution>
    <div class="detailed-solution"><p>Type exactly: Hello World</p></div>
  </solution>
</problem>

Mock Grader Script:

mock_grader.py

How to run this:

STEP 1: GET CREDENTIALS

Run this in your terminal:
tutor config printvalue XQUEUE_AUTH_PASSWORD

STEP 2: PREPARE SCRIPT

IN mock_grader.py. Update the XQUEUE_PASS variable with the password from Step 1.

FOR TUTOR DEV SETUP:

STEP 3: COPY SCRIPT TO CONTAINER & EXECUTE SCRIPT

Run this command (replace tutor_main_dev-lms-1 with your actual LMS container name if different):
docker cp mock_grader.py tutor_main_dev-lms-1:/tmp/mock_grader.py

Run this command to start the interactive grader:
tutor dev exec lms python /tmp/mock_grader.py

FOR TUTOR LOCAL SETUP:

STEP 3: EXECUTE SCRIPT

Run this command:
python mock_grader.py

STEP 5: TEST

1. Go to the LMS browser.
2. Submit an answer to the problem.
3. Look at your terminal. The script will show the student's answer.
4. Enter a score (e.g., 1.0 for correct, 0.0 for incorrect).
5. Enter feedback message.
6. Check LMS to see the grade appear.

Screen.Recording.2026-02-11.at.3.41.12.PM.mov

Related to #36538
Reference openedx/xblocks-contrib#151 (comment)

[kdmccormick]

the code looks good to me 👍🏻 please have another team member look at it too.

could you manually test this? To be honest, I'm not sure exactly how to set up testing for external grading, but I'll ask around.

[kdmccormick]

Suggested change

	'xqueue': XQueueService
	'xqueue': XQueueService,

suggestion-- add a trailing comma

question-- will the runtime automatically construct this with the correct block parameter?

[irtazaakram]

I am not sure how to test it, Still figuring it out. I was hoping that since 'i18n': XBlockI18nService, is supposed to be working and also has block as argument def __init__(self, block=None):, 'xqueue': XQueueService, should work?

[farhan]

Add print statements below the dictionaries and check if they added successfully.
Also see the logs while testing

[kdmccormick]

Dave O tells me that @UsamaSadiq would probably be the most knowledgable person for how to manually test this. Usama, do you mind giving Irtaza pointers on how he could manually changes to the XQueueService class?

I know that we're in the middle of migrating from the XQueue microservice to the in-process edx-submissions backend, and that both are currently supported. My understanding is that the XQueueService class delegates to either one, based on the waffle flag. So we should only need to test one of the backends (xqueue or edx-submissions) in order to validate this PR--whichever backend is easier to set up.

[irtazaakram]

I added some instructions to the PR description on how to test the XQueue Service locally using tutor dev and tutor local. I’ll follow up with @UsamaSadiq to discuss the testing details further.

[farhan]

All seems good,
As per discussion please create a .rst document, how to test it and add its link in the class docs of XQueueService

[farhan]

As part of the ambition to remove xmodule, we should plan to move the Capa block code—that will stay reside in the platform—to a new dedicated location, either now or in a future phase.

We can create a new Django app inside core to house it.

[farhan]

Why do we need to add these declarations now and it was not needed before?

[farhan]

Add print statements below the dictionaries and check if they added successfully.
Also see the logs while testing