feat: add SQL Grader XBlock

[irtazaakram]

This PR moved SQL grader XBlock from https://github.com/openedx/xblock-sql-grader

• Resolves XBlock SQL Grader Migration #10
• Related to Consolidate Optional XBlocks public-engineering#317

Fix: codejail-service REST API support

The original code called codejail.safe_exec() directly, which crashes on Tutor deployments with FileNotFoundError: 'TMPDIR=tmp'. Tutor sets ENABLE_CODEJAIL_REST_SERVICE=True and disables the local sandbox, routing all execution through the codejail-service container instead. See openedx/openedx-platform#36639

Testing

Tested end-to-end on Tutor local with tutor-contrib-codejail (v2 mode, openedx/codejail-service, Python 3.12). xblocks-extra was pip-installed in the sandbox venv via CODEJAIL_EXTRA_PIP_REQUIREMENTS.

  tutor config save \
    --set CODEJAIL_USE_SERVICE_V2=true \
    --set CODEJAIL_SERVICE_V2_VERSION=main \
    --set CODEJAIL_SANDBOX_PYTHON_VERSION=3.12.12 \
    --set "CODEJAIL_EXTRA_PIP_REQUIREMENTS=[\"git+https://github.com/openedx/xblocks-extra.git@add-xblock-sql-grader#egg=xblocks-extra\"]"

  CODEJAIL_DF="$TUTOR_ROOT/env/plugins/codejail/build/codejail-service/Dockerfile"
  sed -i "" "s/    sudo  \\\\/    git \\\\\n    sudo  \\\\/" "$CODEJAIL_DF"
  sed -i "" "s/^ARG SANDBOX_DEPS_VERSION=main$/ARG SANDBOX_DEPS_VERSION=master/" "$CODEJAIL_DF"

Confirmed via codejail-service logs that requests reach the container:

[2026-04-15 06:53:15 +0000] [7] [INFO] POST /api/v0/code-exec

2026-04-15 06:53:15,429 INFO 7 [codejail] [user None] [ip None] jail_code.py:303 - Preparing to execute jailed code 'sql_grader' (overrides context = None, resource limits = {'CPU': 3, 'REALTIME': 3, 'VMEM': 536870912, 'FSIZE': 10485760, 'NPROC': 15, 'PROXY': 0}).

2026-04-15 06:53:15,431 INFO 7 [codejail] [user None] [ip None] subproc.py:47 - Executed jailed code sql_grader in /tmp/codejail-qtkbllzr, with PID 59

The original repository is being deprecated here: openedx/xblock-sql-grader#255

[codecov]

Codecov Report

❌ Patch coverage is 86.98885% with 35 lines in your changes missing coverage. Please review.
✅ Project coverage is 86.98%. Comparing base (d4ad4ac) to head (1491413).
⚠️ Report is 14 commits behind head on main.

Files with missing lines	Patch %	Lines
src/sql_grader/mixins/grading.py	80.26%	14 Missing and 1 partial ⚠️
src/sql_grader/problem.py	90.47%	8 Missing and 2 partials ⚠️
src/sql_grader/xblocks.py	86.66%	4 Missing ⚠️
src/sql_grader/__init__.py	50.00%	2 Missing ⚠️
src/sql_grader/mixins/fragment.py	93.93%	1 Missing and 1 partial ⚠️
src/sql_grader/mixins/scenario.py	77.77%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #18      +/-   ##
==========================================
+ Coverage   79.69%   86.98%   +7.29%     
==========================================
  Files          30        7      -23     
  Lines         778      269     -509     
  Branches       50       23      -27     
==========================================
- Hits          620      234     -386     
+ Misses        136       31     -105     
+ Partials       22        4      -18     

Flag	Coverage Δ
unittests	86.98% <86.98%> (+7.29%)	⬆️

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[irtazaakram]

Added _send_to_codejailservice() which sends code to the codejail-service REST API (/api/v0/code-exec), mirroring the protocol used by the problem XBlock in xblocks_contrib.problem.capa.safe_exec.remote_exec

Modified attempt_safe() to route based on ENABLE_CODEJAIL_REST_SERVICE:
- True → REST API (Tutor / production)
- False → local safe_exec (native installs, unchanged behaviour)

No python_path is sent to the REST API because sql_grader is pip-installed in the sandbox venv at image build time.

This function _send_to_codejailservice was generated with the help of Claude code,

[farhan]

Good work!