Exception: Don't know how to convert the SQLAlchemy field: UUIDType

Hi,

My app crashes with the following mapping:

#error
Exception: Don't know how to convert the SQLAlchemy field item.uuid_column (<class 'sqlalchemy.sql.schema.Column'>)

# model
from sqlalchemy_utils import UUIDType

class Item(Base):
    uuid_column = Column(UUIDType(binary=False), nullable=False, unique=True)

# schema
from graphene_sqlalchemy import SQLAlchemyObjectType

class ItemNode(SQLAlchemyObjectType):
    class Meta:
        model = Item

I tried to put this in my schema file to no avail:

from sqlalchemy_utils import UUIDType
from graphene_sqlalchemy.converter import get_column_doc, is_column_nullable, convert_sqlalchemy_type

@convert_sqlalchemy_type.register(UUIDType)
def convert_column_to_string(type, column, registry=None):
    return graphene.String(description=get_column_doc(column), required=not (is_column_nullable(column)))

I checked the following issues/PR but I don’t get it: 😕

• https://github.com/graphql-python/graphene-sqlalchemy/issues/53
• https://github.com/graphql-python/graphene-sqlalchemy/issues/233
• https://github.com/graphql-python/graphene-sqlalchemy/pull/203

Can someone point me in the right direction with this?

[Msordet]

I found a solution by putting the convert_column_to_string right after the model declaration instead of in the schema file. I don’t really get why so if someone could explain, that’d be nice. 😃

[jbvsmo]

This still doesn’t work for me with the error:

Exception: NonNull could not have a mounted String() as inner type. Try with NonNull(String).

Trying with NonNull(String) give another error

AssertionError: Can only create NonNull of a Nullable GraphQLType