129940b562
After refactoring the library_content block to use asynchronous tasks
for syncing and duplicating children, we are seeing an error arise
during library_content duplication process on edx.org:
Traceback (most recent call last):
File "/edx/app/edxapp/edx-platform/openedx/core/djangoapps/content_libraries/tasks.py", line 305, in duplicate_children
_copy_overrides(store=store, user_id=user_id, source_block=source_block, dest_block=dest_block)
File "/edx/app/edxapp/edx-platform/openedx/core/djangoapps/content_libraries/tasks.py", line 383, in _copy_overrides
dest_block=dest_block.runtime.get_block(dest_child_key),
File "/edx/app/edxapp/edx-platform/xmodule/x_module.py", line 1401, in get_block
block = self.load_item(usage_id, for_parent=for_parent)
File "/edx/app/edxapp/edx-platform/xmodule/modulestore/split_mongo/caching_descriptor_system.py", line 127, in _load_item
block_data = self.get_module_data(block_key, course_key)
File "/edx/app/edxapp/edx-platform/xmodule/modulestore/split_mongo/caching_descriptor_system.py", line 154, in get_module_data
raise ItemNotFoundError(block_key)
xmodule.modulestore.exceptions.ItemNotFoundError: BlockKey(...)
We cannot reproduce the issue locally.
We are not entirely certain the cause of this, but we think it might
have do with caching. Specifically, the `store.get_item` and
`source_block.runtime.get_block` methods might use a different cache
than `dest_block.runtime.get_block`. It's possible that writes to
Mongo are sitting in one of those caches, causing reads from the
`dest_block.runtime`'s cache to fail to find dest_block's children.
We attempt to fix this by using the same "block getting" method
consistently. So instead of using a mix of `store.get_item`,
`source_block.runtime.get_block`, and `dest_block.runtime.get_block`,
we just use `store.get_item` everywhere.
Open edX -------- This is the root package for Open edX. The intent is that all importable code from Open edX will eventually live here, including the code in the lms, cms, and common directories. If you're adding a new Django app, place it in core/djangoapps. If you're adding utilities that require Django, place them in core/djangolib. If you're adding code that defines no Django models or views of its own but is widely useful, put it in core/lib. Note: All new code should be created in this package, and the legacy code will be moved here gradually. For now the code is not structured like this, and hence legacy code will continue to live in a number of different packages.