AttributeError: 'function' object has no attribute '_yield_per' when upgrading to SQLAlchemy 1.4

Traceback (most recent call last):
  File "/Users/mvanbaak/dev/frontrow/public-api/src/fr_public_api/helpers/brandresolver.py", line 36, in resolve_brand_for_apikey
    key = db.session.query(ApiKey).filter_by(key=api_key).one()
  File "/Users/mvanbaak/.dotfiles/virtualenvs/fr_public_api/lib/python3.7/site-packages/aws_xray_sdk/ext/sqlalchemy/util/decorators.py", line 63, in wrapper
    res = func(*args, **kw)
  File "/Users/mvanbaak/.dotfiles/virtualenvs/fr_public_api/lib/python3.7/site-packages/sqlalchemy/orm/query.py", line 2730, in one
    return self._iter().one()
  File "/Users/mvanbaak/.dotfiles/virtualenvs/fr_public_api/lib/python3.7/site-packages/sqlalchemy/orm/query.py", line 2771, in _iter
    execution_options={"_sa_orm_load_options": self.load_options},
  File "/Users/mvanbaak/.dotfiles/virtualenvs/fr_public_api/lib/python3.7/site-packages/aws_xray_sdk/ext/sqlalchemy/util/decorators.py", line 63, in wrapper
    res = func(*args, **kw)
  File "/Users/mvanbaak/.dotfiles/virtualenvs/fr_public_api/lib/python3.7/site-packages/sqlalchemy/orm/session.py", line 1616, in execute
    _parent_execute_state is not None,
  File "/Users/mvanbaak/.dotfiles/virtualenvs/fr_public_api/lib/python3.7/site-packages/sqlalchemy/orm/context.py", line 253, in orm_pre_session_exec
    if "yield_per" in execution_options or load_options._yield_per:
AttributeError: 'function' object has no attribute '_yield_per'

Versions:

Flask==1.1.2
SQLAlchemy==1.4.2
Flask-SQLAlchemy==2.5.1

boto3==1.17.35
botocore==1.20.36
aws-xray-sdk==2.7.0

I get the same error with SQLAlchemy 1.4.0 and 1.4.1, things work fine with 1.3.23.

Confirmed it’s an xray issue with the following change to my code which made things work again:

-db = XRayFlaskSqlAlchemy(model_class=Base)
+db = SQLAlchemy(model_class=Base)

[srprash]

Upon further investigation, i can say that the root cause of this issue is in the method decorate_all_functions which monkey-patches all the non-private functions in the sqlalchemy.orm.Query class with a xray wrapper function.

However, the problem started with v1.4.0 of sqlalchemy where the sqlalchemy.orm.Query class introduced a new non-private member load_options which is of type Class and this load_options member sneaks past this check in xray patching because both functions and classes are callables in Python. Now the load_options is patched as a function whereas this line expects it to be the original class, and therefore the AttributeError occurs.

To test this I modified the check to if name.startswith("_") or name == "load_options": to skip patching the load_options and was able to run the aplication fine. I think the fix for this would be to have a better checking mechanism than callable to differentiate a function from a class.

[srprash]

Hey @peterdeme Yes. The fix was released in v2.8.0 of the SDK. Please see the changelog here:https://github.com/aws/aws-xray-sdk-python/blob/master/CHANGELOG.rst#280 Sorry we missed on updating the issue about the release. I’ll close this now. Feel free to open a new one if you run into any problems. Thanks