docs: [FC-0074] centralize docs for the hooks extension framework

source/conf.py

@@ -100,6 +100,14 @@
         f"https://docs.openedx.org/projects/wordpress-ecommerce-plugin/{rtd_language}/{rtd_version}",
         None,
     ),
+    "openedx-events": (
+        f"https://docs.openedx.org/projects/openedx-events/{rtd_language}/latest",
+        None,
+    ),
+    "openedx-filters": (
+        f"https://docs.openedx.org/projects/openedx-filters/{rtd_language}/latest",
+        None,
+    ),
 }
 
 # Add any paths that contain templates here, relative to this directory.

source/developers/concepts/hooks_extension_framework.rst

@@ -0,0 +1,136 @@
+Hooks Extension Framework
+#########################
+
+What is the Hooks Extension Framework?
+**************************************
+
+Based on the :doc:`edx-platform:concepts/extension_points`, this framework aims to extend the Open edX platform in a maintainable way without modifying its core. The main goal is to leverage the existing extension capabilities provided by the `Open edX Django plugins`_ architecture, allowing developers to implement new features while reducing the need for core modifications and minimizing maintenance efforts.
+
+Hooks are places in the Open edX platform where externally defined functions can take place. These functions may alter what the user sees or experiences on the platform, while in other cases, they are informative only. All hooks are designed to be used along with `Open edX Django plugins`_.
+
+Hooks can be of two types: events and filters. Events are signals sent in specific places whose receivers can extend functionality, while filters are functions that can modify the application's behavior. To allow extension developers to use these definitions in their implementations, both kinds of hooks are defined in lightweight external libraries:
+
+* `openedx-filters`_
+* `openedx-events`_
+
+The framework's main goal is to empower developers to change the platform's functionality as needed while allowing them to migrate to newer Open edX releases with little to no development effort. The framework is designed with stability in mind, meaning it is versioned and backward compatible as much as possible.
+
+A longer description of the framework and its history can be found in :doc:`openedx-proposals:architectural-decisions/oep-0050-hooks-extension-framework`.
+
+Why Adopt the Hooks Extension Framework?
+****************************************
+
+Stable and Maintainable Extensions
+==================================
+
+The Hooks Extension Framework allows developers to extend the platform's functionality in a stable, maintainable, and decoupled way ensuring easier upgrades and long-term stability by removing the need to modify the core in a significant way.
+
+Contained Solution Implementation
+=================================
+
+By avoiding core modifications, the framework promotes self-contained solutions, eliminating the need for custom code to coexist with core logic which lowers maintenance costs for extension developers. As most extensions can now be implementing using the framework, forks are closer to the core and easier to manage.
+
+Leveraging the Open edX Plugin Extension Mechanism
+==================================================
+
+The framework allows developers to implement custom business logic and integrations directly in plugins. This keeps core modifications minimal, focusing maintenance and development efforts on plugins, where solutions can be built and maintained independently of the core platform.
+
+Standardization
+===============
+
+Both filters and events implement approaches for adding additional features, such as communication between services or backend flow control. With these standards in place, it's easy to identify when and how to use the framework as a solution, ensuring a consistent and predictable approach to extending the platform.
+
+Community Compatibility
+=======================
+
+The framework allows for shorter and more agile contribution cycles. By adding standardized extension points, contributors avoid creating customer-specific logic, making development more community-friendly.
+
+Backward Compatibility
+======================
+
+Hooks are designed to be backwards compatible, guaranteeing stability across releases and making it easier to upgrade without breaking existing functionality. This ensures that extensions built on the framework will continue to work as expected across different Open edX versions. See the Architectural Decision Records (ADRs) about versioning for Open edX Events and Filters for more information:
+
+* :doc:`openedx-events:decisions/0002-events-naming-and-versioning`
+* :doc:`openedx-filters:decisions/0004-filters-naming-and-versioning`
+
+Open edX Events and Filters
+***************************
+
+Open edX Events
+===============
+
+Events are Open edX-specific Django signals sent in specific places on the Open edX platform. Developers write code that listens to these signals and performs additional processing based on the event data.
+
+To start using Open edX Events in your project, see the :doc:`Open edX Events <openedx-events:index>` documentation.
+
+Open edX Filters
+================
+
+Filters are functions that can modify the application's behavior by altering input data or halting execution based on specific conditions. They allow developers to implement application flow control based on their business logic or requirements without directly modifying the application code.
+
+To start using Open edX Filters in your project, see the :doc:`Open edX Filters <openedx-filters:index>` documentation.
+
+Differences Between Events and Filters
+=======================================
+
+Here are some key differences between Open edX Events and Filters:
+
++--------------------+------------------------------------------------------------------------+-------------------------------------------------------------+
+|                    | Events                                                                 | Filters                                                     |
++====================+========================================================================+=============================================================+
+| **Purpose**        | Notify when an action occurs in a specific part of the                 | Alter the application flow control.                         |
+|                    | application.                                                           |                                                             |
++--------------------+------------------------------------------------------------------------+-------------------------------------------------------------+
+|  **Usage**         | Used to **extend** functionality via signal receivers when an event is |  Used to intercept and **modify** the data used within a    |
+|                    | triggered.                                                             |  component without directly modifying the application       |
+|                    |                                                                        |  itself.                                                    |
++--------------------+------------------------------------------------------------------------+-------------------------------------------------------------+
+|  **Definition**    |  Defined using the ``OpenEdxPublicSignal`` class, which                |  Defined using the ``OpenEdxPublicFilter`` class,           |
+|                    |  provides a structured way to define the data and                      |  which provides a way to define the filter function         |
+|                    |  metadata associated with the event.                                   |  and the parameters it should receive.                      |
++--------------------+------------------------------------------------------------------------+-------------------------------------------------------------+
+| **Implementation** |  Implemented using `Django signals`_, which allow                      |  Implemented using an accumulative pipeline mechanism which |
+|                    |  developers to send and receive notifications that an action happened  |  takes a set of arguments and returns a modified set        |
+|                    |  within a Django application.                                          |  to the caller or raises exceptions during                  |
+|                    |                                                                        |  processing.                                                |
++--------------------+------------------------------------------------------------------------+-------------------------------------------------------------+
+| **Use cases**      |  Send an email notification when a user enrolls in a course.           |  Prevent the enrollment of non-authorized users.            |
++--------------------+------------------------------------------------------------------------+-------------------------------------------------------------+
+
+How to Know When to Use an Event or a Filter?
+=============================================
+
+When to Use an Open edX Event?
+------------------------------
+
+A developer might use an Open edX Event in order to perform the following actions. Note that this is not an exhaustive list.
+
+- Trigger custom logic or processing in response to specific actions within the platform, e.g., updating a search index after a course block is modified.
+- Communicate, synchronize, or coordinate with other components or services based on specific events or actions, e.g., send certificate data from LMS to credentials service to keep models up to date.
+- Integrate with external systems or services based on specific events or actions, e.g., send user data to third-party services upon registration for marketing purposes.
+
+Fore more detailed use cases, please visit :doc:`openedx-events:reference/real-life-use-cases`.
+
+In summary, events can be used to integrate application components with each other or with external services, allowing them to communicate, synchronize, and perform additional actions when specific triggers occur.
+
+You can review the :doc:`Open edX Events <openedx-events:index>` documentation for more information on :doc:`openedx-events:how-tos/using-events` in your project. This documentation includes a list of :doc:`openedx-events:reference/events` and much more.
+
+When to Use an Open edX Filter?
+-------------------------------
+
+A developer might use an Open edX Filter in order to perform the following actions. Note that this is not an exhaustive list.
+
+- Enrich the data or parameters used to a specific component, e.g., fetch reusable LTI configurations from external plugins.
+- Enforce specific constraints or business rules of a specific component, e.g., don't allow registration for non-authorized email domains.
+- Implement additional features or behavior in a specific component, e.g., add registration extra fields to the user registration form.
+
+Fore more detailed use cases, please visit :doc:`openedx-filters:reference/real-life-use-cases`.
+
+In summary, filters can be used when implementing application flow control that modifies the application's behavior, navigation, or user interaction flow during runtime.
+
+You can review the :doc:`Open edX Filters <openedx-filters:index>` documentation for more information on :doc:`openedx-filters:how-tos/using-filters` in your project. This documentation includes a list of :doc:`openedx-filters:reference/filters` and much more.
+
+.. _Open edX Django plugins: https://edx.readthedocs.io/projects/edx-django-utils/en/latest/plugins/readme.html
+.. _openedx-filters: https://github.com/openedx/openedx-filters
+.. _openedx-events: https://github.com/openedx/openedx-events
+.. _Django signals: https://docs.djangoproject.com/en/4.2/topics/signals/

source/developers/index.rst

@@ -24,6 +24,7 @@ Open edX Developers
 
       * :doc:`references/running_pr_tests`
       * :doc:`references/internal_data_formats/index`
+      * :doc:`concepts/hooks_extension_framework`
 
    .. grid-item-card:: How-tos
       :class-card: sd-shadow-md sd-p-2
@@ -46,6 +47,7 @@ Open edX Developers
       * :doc:`concepts/platform_overview`
       * :doc:`concepts/backend_layout_and_approach`
       * :doc:`concepts/accessibility`
+      * :doc:`concepts/hooks_extension_framework`
       +++
       .. button-ref:: concepts/index
          :color: primary