partial implementation of a pydantic validator to enforce JSON types

json_validator.py

from datetime import datetime
from typing import Dict
from uuid import UUID

from pydantic import BaseModel, validator
from devtools import debug

NoneType = type(None)
json_types = {int, float, bool, NoneType}


class Model(BaseModel):
    a: UUID
    b: datetime
    c: int
    d: Dict[str, int]

    @validator('*', pre=True, each_item=True)
    def json_types_strict(cls, v, field):
        # doesn't yet deal with list and dict
        if field.type_ in json_types:
            assert type(v) == field.type_, f'wrong type, got {type(v).__name__}, expected {field.type_.__name__}'
        # if field.type_ is datetime ...
        return v


m = Model(a='4c4eb481-7576-4a34-b515-ee8cdd7697db', b=1234567890, c=123, d={'x': 1})
debug(m)
"""
test.py:27 <module>
    m: Model(
        a=UUID('4c4eb481-7576-4a34-b515-ee8cdd7697db'),
        b=datetime.datetime(2009, 2, 13, 23, 31, 30, tzinfo=datetime.timezone.utc),
        c=123,
        d={'x': 1},
    ) (Model)
"""


m = Model(a='4c4eb481-7576-4a34-b515-ee8cdd7697db', b=1234567890, c=123.2, d={'x': 1})
"""
pydantic.error_wrappers.ValidationError: 1 validation error for Model
c
  wrong type, got float, expected int (type=assertion_error)
"""