[BD-32] feat: add cohort change Open edX Filter

[mariajgrimaldi]

Description

As part of the Hooks Extension Framework implementation plan, this PR adds a filter before the cohort assignment change process starts.

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==0.6.2

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

4. Configure your filters:
   With this configuration, you won't be able to:

• Change user from cohort org.openedx.learning.cohort.change.requested.v1

OPEN_EDX_FILTERS_CONFIG = {
  "org.openedx.learning.cohort.change.requested.v1": {
          "fail_silently": False,
          "pipeline": [
              "openedx_filters_samples.samples.pipeline.StopCohortChange"
          ]
      },
}

And with this one, the user's profile is modified

OPEN_EDX_FILTERS_CONFIG = {
            "org.openedx.learning.cohort.change.requested.v1": {
                "fail_silently": false,
                "pipeline": [
                    "openedx_filters_samples.samples.pipeline.ModifyUserProfileBeforeCohortChange"
                ]
            }
}

Straightforward implementations as a way of illustrating how they work. More complex steps are coming.

[openedx-webhooks]

Thanks for the pull request, @mariajgrimaldi! I've created BLENDED-1108 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.

[felipemontoya]

This filter is working great. It does as advertised and nothing more.

[felipemontoya]

However by playing around with this I noticed that we are missing a filter for the first time a user is placed in a cohort. This filter only responds to when the user already has a cohort and it is switching.

[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.