PADV-1557 Adjust storage backend definition via site configurations

docs/001-custom-features.md

@@ -31,3 +31,29 @@ This feature allows CCX coaches (ccx_coach in the course access role model) and
 - Find the assignment and grade it.
 - After grading the assignment, it should not be necessary to approve the grade.
 - Go to the progress page, with the student user and check if the grade is assigned to the unit containing the SGA component.
+
+## Custom Storage Backend
+
+### Context
+
+The SGA Xblock in its upstream repository approaches the storage capability by relaying on the Django's default storage
+that is defined in the edx platform. There's also a feature where the storage backend to be used can be defined via
+platform settings. For our fork, this feature adds the capability to define a site-aware backend via site configurations.
+
+### Feature
+
+To define a desired backend, follow the following format by defining the storage class and its kwargs.
+As an example, below you will find the Site Configuration definition to use an AWS S3 bucket:
+
+"SGA_STORAGE_SETTINGS": {
+    "STORAGE_CLASS": "storages.backends.s3boto3.S3Boto3Storage",
+    "STORAGE_KWARGS": {
+        "access_key": "aws_access_key",
+        "secret_key": "aws_secret_key",
+        "bucket_name": "aws-bucket-name",
+        "region_name": "us-east-1"
+    }
+}
+
+Once it has been done, the SGA xblocks for the given site will manage the media objects with the defined storage backend.
+If no settings are defined, the Xblock would use the default Django storage.

edx_sga/tests/test_utils.py

@@ -1,7 +1,7 @@
 """
 Tests for SGA utility functions
 """
-from django.test import override_settings
+from unittest.mock import patch
 from django.core.files.storage import default_storage
 import pytest
 import pytz
@@ -35,23 +35,34 @@ def test_utcnow():
     assert is_near_now(now)
     assert now.tzinfo.zone == pytz.utc.zone
 
-@override_settings(SGA_STORAGE_SETTINGS={
-        'STORAGE_CLASS': 'storages.backends.s3boto3.S3Boto3Storage',
-        'STORAGE_KWARGS':
-            {'bucket_name': 'test', 'location': 'abc/def'}
-    })
-def test_get_default_storage_with_settings_override():
+patch("edx_sga.utils.configuration_helpers")
+def test_get_default_storage_with_settings_override(mock_configuration_helpers):
     """
     get_default_storage should return an S3Boto3Storage object
     """
+    mock_configuration_helpers.return_value.get_value.return_value = (
+        {
+            "SGA_STORAGE_SETTINGS": {
+                "STORAGE_CLASS": "storages.backends.s3boto3.S3Boto3Storage",
+                "STORAGE_KWARGS": {
+                    "access_key": "test_key",
+                    "secret_key": "test_secret",
+                    "bucket_name": "test-bucket-1",
+                    "region_name": "us-east-1",
+                },
+            },
+        },
+    )
     storage = get_default_storage()
     assert storage.__class__ == S3Boto3Storage
     # make sure kwargs are passed through constructor
     assert storage.bucket.name == 'test'
 
-def test_get_default_storage_without_settings_override():
+patch("edx_sga.utils.configuration_helpers")
+def test_get_default_storage_without_settings_override(mock_configuration_helpers):
     """
     get_default_storage should return default_storage object
     """
+    mock_configuration_helpers.return_value.get_value.return_value = {}
     storage = get_default_storage()
     assert storage == default_storage

edx_sga/utils.py

@@ -8,14 +8,14 @@
 from functools import partial
 
 import pytz
-from django.conf import settings
 from django.core.files.storage import default_storage as django_default_storage, get_storage_class
+from openedx.core.djangoapps.site_configuration import helpers as configuration_helpers
 from edx_sga.constants import BLOCK_SIZE
 
 
 def get_default_storage():
     """
-    Get config for storage from settings, use Django's default_storage if no such settings are defined
+    Get config for storage from site configurations, use Django's default_storage if no such settings are defined
     """
     # .. setting_name: SGA_STORAGE_SETTINGS
     # .. setting_default: {}
@@ -25,7 +25,7 @@ def get_default_storage():
     #        STORAGE_CLASS: 'storage',
     #        STORAGE_KWARGS: {}
     #    }
-    sga_storage_settings = getattr(settings, "SGA_STORAGE_SETTINGS", None)
+    sga_storage_settings = configuration_helpers.get_value('SGA_STORAGE_SETTINGS', None)
 
     if sga_storage_settings:
         return get_storage_class(