feat: support frontend plugins via env.config.jsx

This provides a mechanism to configure frontend plugins using a new
PLUGIN_SLOTS filter and a series of patches that modify a base
`env.config.jsx`, in such a way that multiple plugins can take advantage
of the file (including for purposes beyond frontend plugins) without
clobbering each other.

README.rst

@@ -308,6 +308,112 @@ In case you need to run additional instructions just before the build step you c
 
 You can find more patches in the `patch catalog <#template-patch-catalog>`_ below.
 
+Using Frontend Plugin Slots
+~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+It's possible to take advantage of this plugin's hooks to configure frontend plugin slots. Let's say you want to replace the entire footer with a simple message. Where before you might have had to fork ``frontend-component-footer``, the following is all that's currently needed:
+
+.. code-block:: python
+
+    from tutormfe.hooks import PLUGIN_SLOTS
+
+    PLUGIN_SLOTS.add_item((
+        "all", "footer_slot",
+        """
+          {
+            /* Hide the default footer. */
+            op: PLUGIN_OPERATIONS.Hide,
+            widgetId: 'default_contents',
+          },
+          {
+            /* Insert a custom footer. */
+            op: PLUGIN_OPERATIONS.Insert,
+            widget: {
+              id: 'custom_footer',
+              type: DIRECT_PLUGIN,
+              RenderWidget: () => (
+                <h1>This is the footer.</h1>
+              ),
+            },
+          },"""
+    ))
+
+Let's take a closer look at what's happening here.  To begin with, we're using tutormfe's own ``PLUGIN_SLOTS`` filter.  It's a regular Tutor filter, but you won't find it in the main ``tutor`` package:
+
+.. code-block:: python
+
+    from tutormfe.hooks import PLUGIN_SLOTS
+
+    PLUGIN_SLOTS.add_item((
+
+On the following line, the first parameter specifies which MFE to apply the slot configuration to; for example: ``"learner-dashboard"``, or ``"learning"``. We're using ``"all"`` here, which is a special case: it means the slot configuration should be applied to all MFEs that actually have that slot.  (If a particular MFE doesn't have the slot, it will just ignore its configuration.)
+
+The second parameter is the name of the slot:
+
+.. code-block:: python
+
+        "all", "footer_slot",
+
+The last parameter to ``add_item()`` is a big string with the actual slot configuration, which will be interpreted as JSX.  Let's look at the first stanza:
+
+.. code-block:: python
+
+    """
+      {
+        op: PLUGIN_OPERATIONS.Hide,
+        widgetId: 'default_contents',
+      },
+    """
+
+What we're doing here is hiding the default contents of the footer with a ``PLUGIN_OPERATIONS.Hide``. (You can refer to the `frontend-plugin-framework README <https://github.com/openedx/frontend-plugin-framework/#>`_ for a full description of the possible plugin types and operations.)  And the ``default_contents`` widget we're targetting always refers to what's in an unconfigured slot by default.
+
+In the last stanza, we use ``PLUGIN_OPERATIONS.Insert`` to add our custom JSX component, comprised of a simple ``<h1>`` message we're defining in the configuration itself.  We give it a widgetID of ``custom_footer``:
+
+.. code-block:: python
+
+    """
+    op: PLUGIN_OPERATIONS.Insert,
+    widget: {
+      id: 'custom_footer',
+      type: DIRECT_PLUGIN,
+      RenderWidget: () => (
+        <h1>This is the footer.</h1>
+      ),
+    },
+    """
+
+That's it!  If you rebuild the ``mfe`` image after enabling the plugin (via ``tutor images build mfe`` or ``tutor local launch``), "This is the footer." should appear at the bottom of every MFE.
+
+It's also possible to target a specific MFE's footer. For instance:
+
+.. code-block:: python
+
+    PLUGIN_SLOTS.add_item((
+        "profile", "footer_slot",
+        """
+          {
+            /* Hide the global footer we defined earlier. */
+            op: PLUGIN_OPERATIONS.Hide,
+            widgetId: 'custom_footer',
+          },
+          {
+            /* Insert a custom footer specific to the Profile MFE. */
+            op: PLUGIN_OPERATIONS.Insert,
+            widget: {
+              id: 'custom_profile_footer',
+              type: DIRECT_PLUGIN,
+              RenderWidget: () => (
+                <h1>This is the Profile MFE's footer.</h1>
+              ),
+            },
+          },"""
+    ))
+
+Note that here we're assuming you didn't remove the global footer configuration defined by ``"all"``, so you have to hide ``custom_footer`` instead of ``default_contents``.  If you were to rebuild the MFE image now, the Profile MFE's footer would say "This is the Profile MFE's footer", whereas all the others would still contain the global "This is the footer." message.
+
+For more complex frontend plugins, you should make use of ``mfe-env-config-*`` patches to define your JSX components separately.  For instance, you could create an NPM plugin package, install it via ``mfe-dockerfile-post-npm-install``, import the desired components via ``mfe-env-config-static-imports``, then refer to them with the ``PLUGIN_SLOTS`` filter as described above.  Refer to the `patch catalog <#template-patch-catalog>`_ below for more details.
+
+
 Installing from a private npm registry
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
@@ -411,6 +517,60 @@ This is the list of all patches used across tutor-mfe (outside of any plugin). A
     cd tutor-mfe
     git grep "{{ patch" -- tutormfe/templates
 
+mfe-env-config-static-imports
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Use this patch for any additional static imports you need in ``env.config.jsx``. They will be available here if you used the `mfe-docker-post-npm-install patch <#mfe-docker-post-npm-install>`_ to install an NPM package globally.
+
+It gets rendered at the very top of the file. You should use normal `ES6 import syntax <https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/import>`_.
+
+Note that if you want to import a module only on a particular MFE, you can't do it via static imports: you'll have to use the ``mfe-env-config-dynamic-imports-{}`` patch, described below.
+
+File changed: ``tutormfe/templates/mfe/build/mfe/env.config.jsx``
+
+mfe-env-config-head
+~~~~~~~~~~~~~~~~~~~
+
+Use this patch for arbitrary ``env.config.jsx`` javascript code. It gets rendered immediately after static imports, and is particularly useful for defining more complex components for use in plugin slots.
+
+There's currently no version of this patch that runs per MFE, though one could use the MFE-specific ``mfe-env-config-dynamic-imports-{}`` to achieve the same effect.
+
+File changed: ``tutormfe/templates/mfe/build/mfe/env.config.jsx``
+
+mfe-env-config-dynamic-imports
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+This patch gets rendered inside an ``async`` function in ``env.config.jsx`` that runs in the browser, allowing you to define conditional imports for external modules that may only be available at runtime. Just make sure to use `import() function <https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/import>`_ syntax:
+
+.. code-block:: javascript
+
+    const mymodule1 = await import('mymodule1');
+    const { mycomponent1, mycomponent2 } = await import('mymodule2');
+
+Note that if any module is not available at runtime, ``env.config.jsx`` execution will fail silently.
+
+File changed: ``tutormfe/templates/mfe/build/mfe/env.config.jsx``
+
+mfe-env-config-dynamic-imports-{}
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+With this patch you can conditionally import a module for specific MFEs in ``env.config.jsx``. This is a useful place to put an import if you're using the ``mfe-docker-post-npm-install-*`` patch to install a plugin that only works on a particular MFE.
+
+As above, make sure to use the ``import()`` function.
+
+You can also use this patch to insert arbitrary code that will only run on a specific MFE.
+
+File changed: ``tutormfe/templates/mfe/build/mfe/env.config.jsx``
+
+mfe-env-config-tail
+~~~~~~~~~~~~~~~~~~~
+
+At this point, ``env.config.jsx`` is ready to return the ``config`` object to the initialization code. You can use this patch to do anything to the object, including using modules that were imported dynamically earlier.
+
+There's no MFE-specific version of this patch, but you can achieve the same effect by checking the ``process.env.npm_package_name`` variable in the Javascript code you insert.  Refer to the ``env.config.jsx`` template in this repository for an example of how to do that.
+
+File changed: ``tutormfe/templates/mfe/build/mfe/env.config.jsx``
+
 mfe-lms-development-settings
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 

changelog.d/20241111_172451_arbrandes_frontend_plugin_support.md

@@ -0,0 +1 @@
+- [Improvement] Adds support for frontend plugin slot configuration via env.config.jsx. (by @arbrandes)

tutormfe/hooks.py

@@ -13,3 +13,5 @@
 MFE_ATTRS_TYPE = t.Dict[t.Literal["repository", "port", "version"], t.Union["str", int]]
 
 MFE_APPS: Filter[dict[str, MFE_ATTRS_TYPE], []] = Filter()
+
+PLUGIN_SLOTS: Filter[tuple[str, str, str], []] = Filter()

tutormfe/plugin.py

@@ -13,7 +13,7 @@
 from tutor.types import Config, get_typed
 
 from .__about__ import __version__
-from .hooks import MFE_APPS, MFE_ATTRS_TYPE
+from .hooks import MFE_APPS, MFE_ATTRS_TYPE, PLUGIN_SLOTS
 
 # Handle version suffix in nightly mode, just like tutor core
 if __version_suffix__:
@@ -73,7 +73,6 @@
     },
 }
 
-
 # The core MFEs are added with a high priority, such that other users can override or
 # remove them.
 @MFE_APPS.add(priority=tutor_hooks.priorities.HIGH)
@@ -90,6 +89,14 @@ def get_mfes() -> dict[str, MFE_ATTRS_TYPE]:
     return MFE_APPS.apply({})
 
 
+@functools.lru_cache(maxsize=None)
+def get_plugin_slots(mfe_name: str) -> list[tuple[str, str, str]]:
+    """
+    This function is cached for performance.
+    """
+    return [i for i in PLUGIN_SLOTS.apply([]) if i[0] == mfe_name]
+
+
 @tutor_hooks.Actions.PLUGIN_LOADED.add()
 def _clear_get_mfes_cache(_name: str) -> None:
     """
@@ -107,6 +114,15 @@ def iter_mfes() -> t.Iterable[tuple[str, MFE_ATTRS_TYPE]]:
     yield from get_mfes().items()
 
 
+def iter_plugin_slots(mfe_name: str) -> t.Iterable[tuple[str, str, str]]:
+    """
+    Yield:
+
+        (mfe_name, slot_name, slot_config)
+    """
+    yield from get_plugin_slots(mfe_name)
+
+
 def is_mfe_enabled(mfe_name: str) -> bool:
     return mfe_name in get_mfes()
 
@@ -120,6 +136,7 @@ def get_mfe(mfe_name: str) -> MFE_ATTRS_TYPE:
     [
         ("get_mfe", get_mfe),
         ("iter_mfes", iter_mfes),
+        ("iter_plugin_slots", iter_plugin_slots),
         ("is_mfe_enabled", is_mfe_enabled),
     ]
 )

tutormfe/templates/mfe/build/mfe/Dockerfile

@@ -62,6 +62,7 @@ ENV PUBLIC_PATH='/{{ app_name }}/'
 # So we point to a relative url that will be a proxy for the LMS.
 ENV MFE_CONFIG_API_URL=/api/mfe_config/v1
 ARG ENABLE_NEW_RELIC=false
+COPY env.config.jsx /openedx/app
 {{ patch("mfe-dockerfile-pre-npm-build") }}
 {{ patch("mfe-dockerfile-pre-npm-build-{}".format(app_name)) }}
 

tutormfe/templates/mfe/build/mfe/env.config.jsx

@@ -0,0 +1,48 @@
+{{- patch("mfe-env-config-static-imports") }}
+
+{{- patch("mfe-env-config-head") }}
+
+async function getConfig () {
+  let config = {};
+
+  try {
+    /* We can't assume FPF exists, as it's not declared as a dependency in all
+     * MFEs, so we import it dynamically. In addition, for dynamic imports to
+     * work with Webpack all of the code that actually uses the imported module
+     * needs to be inside the `try{}` block.
+     */
+    const { DIRECT_PLUGIN, PLUGIN_OPERATIONS } = await import('@openedx/frontend-plugin-framework');
+    {{- patch("mfe-env-config-dynamic-imports") }}
+
+    config = {
+      pluginSlots: {
+        {%- for _, slot_name, slot_config in iter_plugin_slots("all") %}
+        {{ slot_name }}: {
+          keepDefault: true,
+          plugins: [
+            {{- slot_config }}
+          ]
+        },
+        {%- endfor %}
+      }
+    };
+
+    {%- for app_name, app in iter_mfes() %}
+    if (process.env.npm_package_name == '@edx/frontend-app-{{ app_name }}') {
+      {{- patch("mfe-env-config-dynamic-imports-{}".format(app_name)) }}
+
+      {%- for _, slot_name, slot_config in iter_plugin_slots(app_name) %}
+      config.pluginSlots.{{ slot_name }}.plugins.push(
+        {{- slot_config }}
+      );
+      {%- endfor %}
+    }
+    {%- endfor %}
+
+    {{- patch("mfe-env-config-tail") }}
+  } catch { }
+
+  return config;
+}
+
+export default getConfig;