[BD-32] feat: add filter before course about rendering process starts

[mariajgrimaldi]

Description

As part of the Hooks Extension Framework implementation plan, this PR adds a filter before the course about/home rendering process starts. We decided to include both in one PR given that they are quite alike.

Supporting information

• Hooks Extension Framework OEP-50
  ADR(s) on:
• Open edX Filters naming and versioning: about how to identify filters and manage its versions
• Open edX Filters configuration: how to configure filters
• Open edX Filters tooling: what to use to run filters
• Open edX Filters payload: input arguments for filters

Testing instructions

1. Install openedx-filters library:

pip install openedx-filters==0.6.0

2. Implement your pipeline steps in your favorite plugin. We created some as illustration in openedx-filters-samples. We'll be using those in this example.
3. Install openedx-filters-samples

pip install -e git+https://github.com/eduNEXT/openedx-filters-samples.git@master#egg=openedx_filters_samples

4. Configure your filters:

For course about tests you could run this tests

• Render the course about. Instead, an error will be raised or a different template will be rendered.

OPEN_EDX_FILTERS_CONFIG = {
     "org.openedx.learning.course_about.render.started.v1": {
            "fail_silently": False,
            "pipeline": [
                "openedx_filters_samples.samples.pipeline.RenderAlternativeCourseAbout",
            ]
    },
}

• And with this one, you'll be able to give access to "View course from Studio" to non-staff users (just for testing) from the course about without being staff:

OPEN_EDX_FILTERS_CONFIG = {
     "org.openedx.learning.course_about.render.started.v1": {
            "fail_silently": False,
            "pipeline": [
                "openedx_filters_samples.samples.pipeline.StaffViewCourseAbout",
            ]
    },
}

• If you want to redirect to your custom course about, then:

OPEN_EDX_FILTERS_CONFIG = {
     "org.openedx.learning.course_about.render.started.v1": {
            "fail_silently": False,
            "pipeline": [
                "openedx_filters_samples.samples.pipeline.RedirectCustomCourseAbout",
            ]
    },
}

• And if you want to render your own response:

OPEN_EDX_FILTERS_CONFIG = {
     "org.openedx.learning.course_about.render.started.v1": {
            "fail_silently": False,
            "pipeline": [
                "openedx_filters_samples.samples.pipeline.RenderCustomResponse",
            ]
    },
}

[openedx-webhooks]

Thanks for the pull request, @mariajgrimaldi! I've created BLENDED-1120 to keep track of it in Jira. More details are on the BD-32 project page.

When this pull request is ready, tag your edX technical lead.

[mariajgrimaldi]

Hi there! I hope you're doing good 😃

I'm tagging you here since your involvement in either BD-32 or these files (course home & course about). Your expertise in these applications is crucial for us, and that's why we would appreciate a review from any one of you 😀

@ormsbee
@dianakhuang
@UsamaSadiq
@kdmccormick
@felipemontoya

[felipemontoya]

This PR worked beautifully for modifying the behaviour of those pages before rendering. I tested the 8 options and made interlocking steps to stress test the system. I rendered custom pages defined at the plugin with the pipeline steps and also pages made directly as a django.http response.
Overall I'm thrilled to get this merged. There is one place where I think the naming of the exceptions needs to be clearer.

I so wanted this during the last few years! Great work @mariajgrimaldi.

I'll leave the review in request changes so that we solve the exception naming issue before merging. Also we need to squash the changes and if #29949 is merged first, then the library will already be up to date.

[felipemontoya]

This one is tricky. We will pass the html as the input to the fragment and therefore we will need a little change to the signature of the error.
We need to tell the pipeline step developers to return a string. We could call it RenderCustomFragment.

[mariajgrimaldi]

You're right. I opened this PR with your suggestion.

[felipemontoya]

We could also call it course_home_fragment_template, but that might be threading too thin.

[openedx-webhooks]

Thanks for the pull request, @mariajgrimaldi! I've created BLENDED-1182 to keep track of it in Jira. More details are on the BD-32 project page.

When this pull request is ready, tag your edX technical lead.

[kdmccormick]

Hey @mariajgrimaldi . It looks like these new filters would rely on the presence of the deprecated legacy course home views, some or all of which are slated for removal shortly after the Maple Nutmeg cut next week: openedx/public-engineering#50 (there are a couple PRs linked on that DEPR issue which remove the legacy outline and dates tabs). In particular, the COURSE_HOME_USE_LEGACY_FRONTEND=False overrides in your tests makes me think that this PR depends on code paths that won't be around for much longer.

Is this meant to be temporary? If not, is there a way that it could be built that doesn't depend on the legacy frontend views? I haven't directly worked on the Course Home, so forgive me if I'm misunderstanding.

[mariajgrimaldi]

Hi @kdmccormick 😄

Thanks for the heads up. I implemented this some time back and didn't consider the removal of the course home page. As I see it now, we shouldn't add the course home filter knowing the destiny of the course home.

@felipemontoya, do you have any objection?

[felipemontoya]

I would not say I have an objection about removing, if the course home is going away is probably not worth to keep this in the PR. However from the extensibility of the platform we will probably want this same kind of controls for the new experience as well. Be that as a tool similar to filters in the MFEs or as a regular filters in the views that redirect to the MFEs or the APIs that load the data the MFE is showing.

In any case, that will require some definition work and I don't think it should drag the course_about filters into the longer discussion. I'm good if we take a part out of this and continue only with the course_about filter.

[felipemontoya]

We are also ready here since the home fragment was removed.
A squash of the commits would be good though.

[openedx-webhooks]

@mariajgrimaldi 🎉 Your pull request was merged! Please take a moment to answer a two question survey so we can improve your experience in the future.

[edx-pipeline-bot]

EdX Release Notice: This PR has been deployed to the staging environment in preparation for a release to production.

[edx-pipeline-bot]

EdX Release Notice: This PR has been deployed to the production environment.