PrimaryKeyCreator, no parameter are passed to the create_pk method

I want to make an MurmurHash class to create a primary key for a new model instance. I did this class that adheres to the PrimaryKeyCreator protocol:

# https://github.com/hajimes/mmh3
import mmh3

class Mmh3PrimaryKey:
    """
    A client-side generated primary key that follows the MurmurHash (MurmurHash3) spec.
    https://en.wikipedia.org/wiki/MurmurHash
    """

    @staticmethod
    def create_pk(self, *args, **kwargs) -> str:
        return str('some argument in args / kwargs')

and set Meta primary_key_creator_cls like this:

class ErrorServer(HashModel):
    local_hostname: str
    class Meta:
        primary_key_creator_cls = Mmh3PrimaryKey

But when I instantiate ErrorServerclass, no parameter (len of *args, **kwargs == 0) are passed to create_pk

es = ErrorServer(local_hostname='my_hostname', param2='Test')

[DasLukas]

I also need to change the default pk. I use this workaround. Works fine for me.

from pydantic import root_validator

class Foo(JsonModel):
    name: str

    @root_validator(pre=True)
    def overwrite_pk(cls, values: dict[str, Any]):
        def _overwrite_pk(*args, **kwargs):
            return f"{args[0]}.{args[1]}"

        values["pk"] = _overwrite_pk(values["name"])

        return values

foo = Foo(name="test")

print(foo.pk) # -> "test"

[nicolas-rdgs]

I am also interested in changing the default primary key and noticed the same behavior.

I also noticed that the custom class FieldInfo (inherited from Pydantic FieldInfo) has the attribute “primary_key” which is used in the RedisModel class to initiate the default field pk as primary key.

But apparently this attribute cannot be used elsewhere:

Class Customer(HashModel):
    email: EmailStr = Field(index=True, primary_key=True)

--
File ~/.local/lib/python3.9/site-packages/redis_om/model/model.py:1158, in RedisModel.validate_primary_key(cls)
   1156     raise RedisModelError("You must define a primary key for the model")
   1157 elif primary_keys > 1:
-> 1158     raise RedisModelError("You must define only one primary key for a model")

RedisModelError: You must define only one primary key for a model

It would be great to use this parameter like SQL Alchemy ORM to change the default behavior. If we use this parameter manually in another field (declared one time in the model), the latter must have precedence over the pk field. What do you think?