How to dynamically generate models?

[ssbarnea]

I need to generate a very long list of models programately and add them to the root element of the of the TasksModel I am trying to build:

class TasksFileModel(BaseModel):
    __root__: List[Union[TaskModel, BlockModel]]
   # this allows now two models previous defined, but I need to dynamically create and add ~5000 others
   # how can I do this?

    class Config:
        extra = Extra.forbid
        title = "Tasks Schema"

[PrettyWood]

Hmm not sure if this will be very efficient with so many models.
But for the dynamical approach maybe this can inspire you

import string
from typing import Union

from pydantic import BaseModel, create_model, ValidationError

all_models = {
    c: create_model(f'Model{c}', **{c: (str, ...)})
    for c in string.ascii_lowercase
}


class M(BaseModel):
    __root__: Union[tuple(all_models.values())]

M.parse_obj({'a': 'foo'})
M.parse_obj({'b': 'foo'})
try:
    M.parse_obj({'aa': 'foo'})
except ValidationError as e:
    print(e)

[ssbarnea]

Thanks! I am going to give this a try and findout is is doable or not. If this does not work or proves to be too slow, I wonder if I could use some kind of regex matching that verifies that I only have one extra property which has a name that matches my regex.

To elaborate, assume model with several hardcoded properties and one extra one which needs to be a string among a my 5000 values, like below:

name: anything
action1: ...
---
name: anything
action2: ...
---
name: anything
action1: ...
action2: ...
# ^ this one should fail because model should allow only one additional property that is part of my long list, not two.

[samuelcolvin]

@ssbarnea can you make this question as answered if you have what you need. Thanks.

[ssbarnea]

I need few small changes but I was able to make it work. Thanks