AttributeError on google cloud datastore entity object

Question

I have an entity called Author. Below is the ndb class:

class Author(ndb.Model):
    name = ndb.StringProperty()
    website = ndb.StringProperty()
    bio = ndb.StringProperty()
    profile_image_url = ndb.StringProperty()
    slug = ndb.ComputedProperty(lambda self: make_slug(self.name))

I am creating an author object like this

author = Author(id=pk, **author_dict)
author.put()

There is no error when creating an author object for the first time.

I am retrieving an author object like this

author = Author.get_by_id(pk)

when I try to access the author bio field I get an AttributeError

author.bio = bio_text

The error comes when accessing a field on a existing author object. Error does not come on all fields.

The console is showing all the columns. The bio column is present in the datastore console for author entity.

I deleted all the author entities and made new entries. Still I am getting AttributeError.

I have several entities in datastore but I am getting this error only for Author entity.

Error statement:

File "/base/data/home/runtimes/python27/python27_lib/versions/1/google/appengine/ext/ndb/model.py", 
line 2990, in _set_attributes
prop = getattr(cls, name)  # Raises AttributeError for unknown properties.
AttributeError: type object 'Author' has no attribute 'bio'

CLOSED:

I had a class called Author in another module. This class was being used by NDB somehow to create the author entity and was causing this behaviour.

Please can you provide an minimal reproducible example. I can't reproduce this problem with the example code that you have provided. — snakecharmerb
Hi, I have added some more information. I can add the surrounding code but it is unrelated to the error. — zaphod100.10
You can only get this error if "author" is a class, not an instance, and is a class that does not have a bio attribute. So it seems that you are overwriting author somewhere in your code. — snakecharmerb
You could try printing or logging type(author) and author.__name__ just before the line that's failing, to see what author actually is. — snakecharmerb
I tried your suggestion and no matter what fields I have in the Author class, type(Author) is printing Author<author_id=StringProperty('author_id'), name=StringProperty('name'), profile_image_url=StringProperty('profile_image_url')> — zaphod100.10

zaphod100.10 zaphod100.10 · Accepted Answer · 2016-04-29T18:21:20

I had a class called Author in another module. This class was being used as a structured property in another entity class.

Somehow this class was being used by NDB to create the Author entity. I renamed this class and the error was gone.

Now I am using different class names for all ndb entities and structured properties.

AttributeError on google cloud datastore entity object

1 Answers