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Date: April 27, 2022 at 2:00pm, Room -115

Speaker: Felipe Montoya

Intro

https://open-edx-proposals.readthedocs.io/en/latest/architectural-decisions/oep-0050-hooks-extension-framework.html

https://github.com/openedx/openedx-events

https://github.com/openedx/openedx-filters

Blended project led by edunext with edX as a collaborator.

Nutmeg will have the full implementation.

Hooks are a stable list of places in the life cycle of the learners and authors where externally defined functions can take place.

Example: Start > Register > Enroll > Learn > Certificate. Hooks can happen immediately before and after each of the >s.

Depending on what’s expected from them, there are two types of hooks: events and filters.

Events:

• Features:

  • Doesn’t halt the application execution

  • Sent to receivers after performing an action

  • The main design goal of openedx-events is stability

  • They live in a separate Python library (openedx-events)

  • Definitions are versioned to increase their reliability

  • Documented with key information using in-line documentation

• Implementation:

  • Open edX standardized Django signals

  • An event sends Data Attribute classes instead of in-memory obejcts

  • Events run in-process but the Event Bus will take them everywhere

  • The event bus is one of the reasons why they are named after the OEP-41

Filters:

• Features:

  • Affect the application execution

  • Give the Open edX developer total control over the process where it runs, allowing them to manipulate in-memory objects

  • The main design goal of openedx-filters is flexibility

  • The definitions are documented with key information using in-line documentation

  • Definitions are versioned to increase reliability

• Implementation:

  • They live in a separate Python library (openedx-filters)

  • Executes a list of functions just before performing an action

  • The filters tooling is based on a pipeline mechanism inspired by the Social Core pipeline

  • Named after OEP-41

  • Configured using Django settings

List of current event/filters

https://github.com/openedx/openedx-events/blob/main/openedx_events/learning/signals.py#L44-L53

https://github.com/openedx/openedx-filters/blob/main/openedx_filters/learning/filters.py (still under implementation)

Example

https://github.com/eduNEXT/openedx-filters-samples

How to create new events/filters

• Creating an Open edX Event

  • Create the data attributes for the event (OEP-49)

  • Create the event definition

  • Integrate into service

• Creating an Open edX Filter

  • Create the filter definition

  • Integrate into service