init_beanie cannot initialize some collections

Question

Having a well described model and schema using Pydantic and Beanie syntax, there are some collections, represented by their Document classes, which are not been initialized by init_beanie function at the startup event of a Fastapi app.

Did someone know what could be the causes of such a behavior?

Fastapi-users set a very special class named User, which is one of the well initialized by the background Beanie engine. After that, I added my entire model which consists in several classes.

For example, from my product_category module:

from typing import Optional    
from beanie import Document, Indexed    

class ProductCategory(Document):
    category: Indexed(str, unique=True)
    description: Optional[str]

    class Settings:
        name = "product_categories"

From my product_subcategory module:

from typing import Optional    
from beanie import Document, Link    
from product_category import ProductCategory
    
class ProductSubcategory(Document):
    category_id: Link[ProductCategory]
    subcategory: str
    description: Optional[str]

    class Settings:
        name = "product_subcategories"

...and so. The outcome of init_beanie reflects an initialization of a collection named ProductCategory, not product_categories as I think it would happened, because of the Settings inner class with its property "name", and that's it.

Such a behavior is not documented, and that's why I assume I'm making something wrong. Can anyone know how to fix this?

Thanks in advance. Jorge Olmedo.

Answer 1

As far as I know, and using the information I can gather from a couple of Python enthusiasts and collaborators:

• Roman Right: [https://github.com/roman-right], author of Beanie ODM
• Francois Voron: [https://github.com/frankie567], Fastapi_users maintainer

...issue was solved. It goes like this: It seems Beanie have some problems to follow relative paths at import clause. All I did was changed all my relative module paths for absolute module paths, and that's it.

Answer 2

We had a similar issue. When trying to load and change a document from the database it failed. The error looked like this:

Traceback (most recent call last):
  File "/usr/lib/python3.10/runpy.py", line 196, in _run_module_as_main
    return _run_code(code, main_globals, None,
  File "/usr/lib/python3.10/runpy.py", line 86, in _run_code
    exec(code, run_globals)
  File "/code/app/main.py", line 280, in <module>
    asyncio.run(main())
  File "/usr/lib/python3.10/asyncio/runners.py", line 44, in run
    return loop.run_until_complete(main)
  File "/usr/lib/python3.10/asyncio/base_events.py", line 646, in run_until_complete
    return future.result()
  File "/code/app/main.py", line 204, in main
    await rad.set({MyDocument.status: Status.IN_PROGRESS})
AttributeError: 'NoneType' object has no attribute 'set'

We figured out that the reference to the document represented by the identifier rad was None because it was not able to load it from the database using this:

rad = MyDocument.find_one(MyDocument.id == args.rid)

The first problem was that we forgot to provide the correct collection name in the Document class. We had to add inner Settings class with a name property containing the name of collection.

Before:

class MyDocument(Document):
    id: uuid.UUID = None
    status: Status = None

After:

class MyDocument(Document):
    id: uuid.UUID = None
    status: Status = None
    class Settings:
        name = "theCorrectCollectionName"

Do not forget to call the init_beanie method. Otherwise the Settings class will be ignored (See links below).

In the end we did the following things to make it work:

• Upgrade from beanie 1.10.4 to 1.20.0

• Use absolute imports instead of relative imports for our self written code like so (As mentioned also in this answer but without example: https://stackoverflow.com/a/74033006/3623232)

  Before:

  import cfg
  from models import MyDocument, Status
  

  Afterwards:

  import app.cfg as cfg
  from app.models import MyDocument, Status
  

  The assumption here is that the there exist files cfg.py and models.py in a folder app that also contains an empty __init__.py file to mark the app folder as a module.

Related links:

• Regarding Settings configuration: https://beanie-odm.dev/tutorial/defining-a-document/
• Regarding beanie initialization: https://beanie-odm.dev/tutorial/initialization/
• Absolute vs relative paths in python: https://realpython.com/absolute-vs-relative-python-imports/