Why does SQLAlchemyCRUDRouter require all fields? Even the optional ones?

[afparsons]

Problem

Using the example below, the POST route created by SQLAlchemyCRUDRouter requires values for created_at and updated_at. Adding = None as a default value to the Pydantic schema doesn't change this behavior. These fields are listed as required in Redoc and Swagger. Similarly, making a request results in the following error:

{"detail":[{"loc":["body","created_at"],"msg":"field required","type":"value_error.missing"},{"loc":["body","updated_at"],"msg":"field required","type":"value_error.missing"}]}

Meanwhile, my own POST function available at /create-record does not require these fields (expected behavior).

Semi-pseudocode

# models.py

from sqlalchemy ...

@as_declarative()
class Base:
    """
    Elided: primary key field, dynamic table name generation, and some methods
    """

@declarative_mixin
class MixinTimestamps:
    created_at = Column(
        DateTime,
        nullable=True,
        server_default=func.now(),
    )

    updated_at = Column(
        DateTime,
        nullable=True,
        server_default=func.now(),
        server_onupdate=func.now(),
    )

class Record(Base, MixinTimestamps):
    """
    Elided: Record-specific fields (other models also implement MixinTimestamps)
    """

# schemas.py

from pydantic import ...

class MixinTimestamps(BaseModel):
    created_at: Optional[datetime]
    updated_at: Optional[datetime]

class Record(MixinTimestamps):
    """
    Elided: Record-specific fields (other schemas also implement MixinTimestamps)
    """
    
    class Config:
        orm_mode = True
        extra: str = Extra.ignore
    

# main.py

from .database import get_database_session
from .models import Record
from .schemas import Record as SchemaRecord

app = FastAPI()

app.include_router(
    router=SQLAlchemyCRUDRouter(
        schema=SchemaRecord,
        db_model=Record,
        db=get_database_session,
        tags=[Record.__name__],
    )
)

@app.post('/create-record')
def create_rule(record: SchemaRecord):
    return record.json()

Questions

1. Why is this happening?
2. What is the remedy?
3. Should I file a bug report?

[afparsons]

@awtkns beep boop, polite bump

[iagobalmeida]

Have you tried setting some default values for the Optional fields?

from pydantic import ...

class MixinTimestamps(BaseModel):
    created_at: Optional[datetime] = None
    updated_at: Optional[datetime] = None

class Record(MixinTimestamps):
    """
    Elided: Record-specific fields (other schemas also implement MixinTimestamps)
    """
    
    class Config:
        orm_mode = True
        extra: str = Extra.ignore