pydantic-modelable 0.3.0

A set of pydantic utilities, to extend models on package load

pydantic-modelable

A set of utilities around pydantic that allows to create extensible pydantic models, with little code, in an aim to have models extended by third-party python code.

Features

Using pydantic for type modelisation and validation has become a very common practice. That being said, some advanced uses are not natively supported, although the pydantic types are extremely flexible, such as dynamic extensibility of the models.

It can be very useful to define extensible models relying on this mechanism, and pydantic_modelable, as it may provide the following benefits:

• Reduction of code maintenance (defining an "extension" registers it automatically wherever the base was setup)
• Easy extension of a core library's models and features through the loading of extension modules
• Automatically updated Model schemas for inclusion in any schema-based tooling or framework (ex: FastAPI's OpenAPI Schema generation tooling)

With a few additional parameters to your model's constructor, inheriting from pydantic_modelable.Modelable, you can thus configure specific behaviors for your extensible model:

• discriminated union: discriminator=attr_name

You can then register other models into your base model using decorators embedded into your base model by the pydantic_modelable.Modelable class:

• extends_enum
• extends_union(dicriminated_union_attr_name: str)
• as_attribute(attr_name: str, optional: bool, default_factory: Callable[[], BaseModel])

Limitations

As pydantic-modelable relies on altering the pydantic models at runtime, the type-checking tools are usually not able to understand that the model was extended and its type signature was changed. This, sadly, often leads to an extensive use of #type: ignore directives in the code relating to the use of the extended models.