refactor: use collection usage_key as search document id

This change standardises the search document "id" to be a meilisearch ID
generated from the usage key, for all types of indexed objects.

This is important for collections so we can locate the collection
document in the search index solely from the data provided by the
LIBRARY_COLLECTION_DELETED event (library_key + collection_key), even if
the collection has been deleted from the database.

openedx/core/djangoapps/content/search/api.py

@@ -34,6 +34,7 @@
     searchable_doc_for_course_block,
     searchable_doc_for_collection,
     searchable_doc_for_library_block,
+    searchable_doc_for_usage_key,
     searchable_doc_collections,
     searchable_doc_tags,
     searchable_doc_tags_for_collection,

openedx/core/djangoapps/content/search/documents.py

@@ -112,6 +112,15 @@ def _meili_access_id_from_context_key(context_key: LearningContextKey) -> int:
     return access.id
 
 
+def searchable_doc_for_usage_key(usage_key: UsageKey) -> dict:
+    """
+    Generates a base document identified by its usage key.
+    """
+    return {
+        Fields.id: meili_id_from_opaque_key(usage_key),
+    }
+
+
 def _fields_from_block(block) -> dict:
     """
     Given an XBlock instance, call its index_dictionary() method to load any
@@ -297,14 +306,14 @@ def searchable_doc_for_library_block(xblock_metadata: lib_api.LibraryXBlockMetad
     library_name = lib_api.get_library(xblock_metadata.usage_key.context_key).title
     block = xblock_api.load_block(xblock_metadata.usage_key, user=None)
 
-    doc = {
-        Fields.id: meili_id_from_opaque_key(xblock_metadata.usage_key),
+    doc = searchable_doc_for_usage_key(xblock_metadata.usage_key)
+    doc.update({
         Fields.type: DocType.library_block,
         Fields.breadcrumbs: [],
         Fields.created: xblock_metadata.created.timestamp(),
         Fields.modified: xblock_metadata.modified.timestamp(),
         Fields.last_published: xblock_metadata.last_published.timestamp() if xblock_metadata.last_published else None,
-    }
+    })
 
     doc.update(_fields_from_block(block))
 
@@ -319,9 +328,7 @@ def searchable_doc_tags(usage_key: UsageKey) -> dict:
     Generate a dictionary document suitable for ingestion into a search engine
     like Meilisearch or Elasticsearch, with the tags data for the given content object.
     """
-    doc = {
-        Fields.id: meili_id_from_opaque_key(usage_key),
-    }
+    doc = searchable_doc_for_usage_key(usage_key)
     doc.update(_tags_for_content_object(usage_key))
 
     return doc
@@ -332,9 +339,7 @@ def searchable_doc_collections(usage_key: UsageKey) -> dict:
     Generate a dictionary document suitable for ingestion into a search engine
     like Meilisearch or Elasticsearch, with the collections data for the given content object.
     """
-    doc = {
-        Fields.id: meili_id_from_opaque_key(usage_key),
-    }
+    doc = searchable_doc_for_usage_key(usage_key)
     doc.update(_collections_for_content_object(usage_key))
 
     return doc
@@ -348,15 +353,11 @@ def searchable_doc_tags_for_collection(
     Generate a dictionary document suitable for ingestion into a search engine
     like Meilisearch or Elasticsearch, with the tags data for the given library collection.
     """
-    doc = {
-        Fields.id: collection.id,
-    }
-
     collection_usage_key = lib_api.get_library_collection_usage_key(
         library_key,
         collection.key,
     )
-
+    doc = searchable_doc_for_usage_key(collection_usage_key)
     doc.update(_tags_for_content_object(collection_usage_key))
 
     return doc
@@ -368,44 +369,42 @@ def searchable_doc_for_course_block(block) -> dict:
     like Meilisearch or Elasticsearch, so that the given course block can be
     found using faceted search.
     """
-    doc = {
-        Fields.id: meili_id_from_opaque_key(block.usage_key),
+    doc = searchable_doc_for_usage_key(block.usage_key)
+    doc.update({
         Fields.type: DocType.course_block,
-    }
+    })
 
     doc.update(_fields_from_block(block))
 
     return doc
 
 
-def searchable_doc_for_collection(collection) -> dict:
+def searchable_doc_for_collection(
+    library_key: LibraryLocatorV2,
+    collection_key: str,
+    *,
+    # Optionally provide the collection if we've already fetched one
+    collection: Collection | None = None,
+) -> dict:
     """
     Generate a dictionary document suitable for ingestion into a search engine
     like Meilisearch or Elasticsearch, so that the given collection can be
     found using faceted search.
     """
-    doc = {
-        Fields.id: collection.id,
-        Fields.block_id: collection.key,
-        Fields.type: DocType.collection,
-        Fields.display_name: collection.title,
-        Fields.description: collection.description,
-        Fields.created: collection.created.timestamp(),
-        Fields.modified: collection.modified.timestamp(),
-        # Add related learning_package.key as context_key by default.
-        # If related contentlibrary is found, it will override this value below.
-        # Mostly contentlibrary.library_key == learning_package.key
-        Fields.context_key: collection.learning_package.key,
-        Fields.num_children: collection.entities.count(),
-    }
-    # Just in case learning_package is not related to a library
+    collection_usage_key = lib_api.get_library_collection_usage_key(
+        library_key,
+        collection_key,
+    )
+
+    doc = searchable_doc_for_usage_key(collection_usage_key)
+
     try:
         context_key = collection.learning_package.contentlibrary.library_key
         org = str(context_key.org)
         doc.update({
             Fields.context_key: str(context_key),
             Fields.org: org,
-            Fields.usage_key: str(lib_api.get_library_collection_usage_key(context_key, collection.key)),
+            Fields.usage_key: str(collection_usage_key),
         })
     except LearningPackage.contentlibrary.RelatedObjectDoesNotExist:
         log.warning(f"Related library not found for {collection}")

openedx/core/djangoapps/content/search/tests/test_api.py

@@ -187,7 +187,7 @@ def setUp(self):
             )
             self.collection_usage_key = "lib-collection:org1:lib:MYCOL"
         self.collection_dict = {
-            "id": self.collection.id,
+            "id": "lib-collectionorg1libmycol-5b647617",
             "block_id": self.collection.key,
             "usage_key": self.collection_usage_key,
             "type": "collection",
@@ -461,7 +461,7 @@ def test_index_library_block_and_collections(self, mock_meilisearch):
         # Build expected docs at each stage
         lib_access, _ = SearchAccess.objects.get_or_create(context_key=self.library.key)
         doc_collection1_created = {
-            "id": collection1.id,
+            "id": "lib-collectionorg1libcol1-283a79c9",
             "block_id": collection1.key,
             "usage_key": f"lib-collection:org1:lib:{collection1.key}",
             "type": "collection",
@@ -476,7 +476,7 @@ def test_index_library_block_and_collections(self, mock_meilisearch):
             "breadcrumbs": [{"display_name": "Library"}],
         }
         doc_collection2_created = {
-            "id": collection2.id,
+            "id": "lib-collectionorg1libcol2-46823d4d",
             "block_id": collection2.key,
             "usage_key": f"lib-collection:org1:lib:{collection2.key}",
             "type": "collection",
@@ -491,7 +491,7 @@ def test_index_library_block_and_collections(self, mock_meilisearch):
             "breadcrumbs": [{"display_name": "Library"}],
         }
         doc_collection2_updated = {
-            "id": collection2.id,
+            "id": "lib-collectionorg1libcol2-46823d4d",
             "block_id": collection2.key,
             "usage_key": f"lib-collection:org1:lib:{collection2.key}",
             "type": "collection",
@@ -506,7 +506,7 @@ def test_index_library_block_and_collections(self, mock_meilisearch):
             "breadcrumbs": [{"display_name": "Library"}],
         }
         doc_collection1_updated = {
-            "id": collection1.id,
+            "id": "lib-collectionorg1libcol1-283a79c9",
             "block_id": collection1.key,
             "usage_key": f"lib-collection:org1:lib:{collection1.key}",
             "type": "collection",
@@ -593,14 +593,14 @@ def test_index_tags_in_collections(self, mock_meilisearch):
 
         # Build expected docs with tags at each stage
         doc_collection_with_tags1 = {
-            "id": self.collection.id,
+            "id": "lib-collectionorg1libmycol-5b647617",
             "tags": {
                 'taxonomy': ['A'],
                 'level0': ['A > one', 'A > two']
             }
         }
         doc_collection_with_tags2 = {
-            "id": self.collection.id,
+            "id": "lib-collectionorg1libmycol-5b647617",
             "tags": {
                 'taxonomy': ['A', 'B'],
                 'level0': ['A > one', 'A > two', 'B > four', 'B > three']

openedx/core/djangoapps/content/search/tests/test_documents.py

@@ -303,7 +303,7 @@ def test_collection_with_library(self):
         doc.update(searchable_doc_tags_for_collection(self.library.key, self.collection))
 
         assert doc == {
-            "id": self.collection.id,
+            "id": "lib-collectionedx2012_falltoy_collection-d1d907a4",
             "block_id": self.collection.key,
             "usage_key": self.collection_usage_key,
             "type": "collection",