pydantic.errors.PydanticImportError: `BaseSettings` has been moved to the `pydantic-settings` package

[harupy]

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How to reproduce:

docker run -it python:3.9 bash
>>> pip install mlserver
>>> python -c "import mlserver"

Package versions:

> pip list | grep mlserver
mlserver                                 1.4.0

> pip list | grep pydantic
pydantic                                 2.6.3
pydantic_core                            2.16.3

Traceback:

/usr/local/lib/python3.9/site-packages/pydantic/_migration.py:283: UserWarning: `pydantic.error_wrappers:ValidationError` has been moved to `pydantic:ValidationError`.
  warnings.warn(f'`{import_path}` has been moved to `{new_location}`.')
/usr/local/lib/python3.9/site-packages/pydantic/_migration.py:283: UserWarning: `pydantic:PyObject` has been moved to `pydantic.types:ImportString`.
  warnings.warn(f'`{import_path}` has been moved to `{new_location}`.')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/local/lib/python3.9/site-packages/mlserver/__init__.py", line 2, in <module>
    from .server import MLServer
  File "/usr/local/lib/python3.9/site-packages/mlserver/server.py", line 7, in <module>
    from mlserver.repository.factory import ModelRepositoryFactory
  File "/usr/local/lib/python3.9/site-packages/mlserver/repository/__init__.py", line 1, in <module>
    from .repository import (
  File "/usr/local/lib/python3.9/site-packages/mlserver/repository/repository.py", line 8, in <module>
    from ..settings import ModelParameters, ModelSettings
  File "/usr/local/lib/python3.9/site-packages/mlserver/settings.py", line 8, in <module>
    from pydantic import PyObject, Extra, Field, BaseSettings as _BaseSettings
  File "/usr/local/lib/python3.9/site-packages/pydantic/__init__.py", line 374, in __getattr__
    return _getattr_migration(attr_name)
  File "/usr/local/lib/python3.9/site-packages/pydantic/_migration.py", line 296, in wrapper
    raise PydanticImportError(
pydantic.errors.PydanticImportError: `BaseSettings` has been moved to the `pydantic-settings` package. See https://docs.pydantic.dev/2.6/migration/#basesettings-has-moved-to-pydantic-settings for more details.

For further information visit https://errors.pydantic.dev/2.6/u/import-error

[sakoush]

@harupy many thanks for your issue, we have not migrated yet mlserver to use pydantic v2 and until we do the short-term fix is to downgrade your pydantic dependency in your env to v1.

[privatedumbo]

@sakoush , you probably are aware, but just in case, there is an issue about making this compatible with (or supporting) Pydantic v2.

[tomityrrell]

@jesse-c Any plans yet to release a pydantic v2 compatible version?

[jesse-c]

Hi @tomityrrell, it's out of my hands now! @sakoush is one of those who are involved in a release happening.

[sakoush]

@tomityrrell we are planning to have a release of mlserver soon that will include pydantic v2 upgrade in the next couple of weeks.