Refactor: LaTeX processing in external Docker container

[b0ink]

Depends on doubtfire-lms/doubtfire-deploy#29

Description

This update moves LaTeX processing into a dedicated TeX Live container. Instead of running lualatex from the latex_config, the latex_run.sh script is executed after being copied into the working directory (along with other input files such as input.tex and jupynotex.py).

latex_run.sh then runs docker exec ... into the TeX Live container and executes latex_build.sh, which is in charge of running the lualatex commands.

latex_run.sh relies on two environment variables to be set:

LATEX_CONTAINER_NAME=formatif-texlive-container # Name of the TeX Live container
LATEX_BUILD_PATH=/texlive/shell/latex_build.sh # Path on the TeX Live container

The render_to_string() method that renders the PDFs is now wrapped in a generate_pdf() method defined in latex_helper.rb, ensuring the environment variables are set before executing latex_run.sh via render_to_string.

Type of change

• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

• Use the modified docker-compose from Refactor: External TeX Live docker container doubtfire-deploy#29
• If you encounter issues with the setup, remove any previous Docker devcontainer builds and volumes.
• Run rake test in doubtfire-api to validate PDF generation.
• Optionally, run rake db:simulate_signoff which will create several tasks and render them with lualatex.
• You can also manually create a portfolio when logged in as a student, upload different test files, click "Create my portfolio", then run doubtfire-api/lib/shell/generate_pdfs.sh

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation if appropriate
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• I have created or extended unit tests to address my new additions
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules

[macite]

Hi @b0ink, it looks like the merge commit fb0bc26 has not merged the change log well. Can you recreate the PR and merge into the new/scorm branch? You could just revert the last two merge commits, and then force push to your branch. That may update this PR...

[macite]

We also probably need to make sure to update the GitHub actions so that it tests using the separate containers

[macite]

Looks pretty close now - just a few minor things to look at.

[macite]

We should check that these environment variables exist - either here or in the application.rb file. Then report an error so that the config can be checked.
$LATEX_CONTAINER_NAME
$LATEX_BUILD_PATH

[macite]

Should we default LATEX_BUILD_PATH to /texlive/shell/latex_build.sh if it is not set?