Python - Pydantic serialiser transform in other model

I want to use Pydantic 2 to export data to a Kafka Sub Queue and I need to export to JSON in a different model.

For example I have following object:

class obj(BaseModel):
  resource: str
  resourceid: int
  resourceTime: datetime
  name: str
  option1: str
  option2: int
  
{
  "resource": "TEST",
  "resourceid": "1234",
  "resourceTime": "2024-09-03 00:00:00",
  "option1": "test",
  "option2": 23421,
  "name": "test"
}

But I need to dump in this way:

{
  "resource": "TEST",
  "name": "test,
  "resourceid": "1234",
  "resourceTime": "2024-09-03 00:00:00",
  "attributes": [
    {
      "name": "option1",
      "value": "test",
    },
    {
      "name": "option2",
      "value": 23421
    },
    {
      "name": "name",
      "value": "test"
    }
  ]    
}

There is a possibility to use some functionality of Pydantic to achieve this?

Thanks.

You can use model_serializer:

from datetime import datetime

from pydantic import BaseModel, Field, model_serializer

class obj(BaseModel):
    resource: str
    resourceid: int
    resourceTime: datetime
    name: str
    option1: str = Field(exclude=True)
    option2: int = Field(exclude=True)

    @model_serializer(mode="wrap")
    def _serialize(self, handler):
        d = handler(self)
        d["resourceid"] = str(d["resourceid"])
        d["attributes"] = [
            {
                "name": "option1",
                "value": self.option1
            },
            {
                "name": "option2",
                "value": self.option2
            },
            {
                "name": "name",
                "value": self.name
            },
        ]
        return d

o = obj.model_validate(
    {
        "resource": "TEST",
        "resourceid": "1234",
        "resourceTime": "2024-09-03 00:00:00",
        "option1": "test",
        "option2": 23421,
        "name": "test"
    }
)

print(o.model_dump())

UPD:

To achieve dynamic behavior you can do something like this:

class obj(BaseModel):
    resource: str
    resourceid: int
    resourceTime: datetime
    name: str
    option1: str = Field(exclude=True)
    option2: int = Field(exclude=True)

    @model_serializer(mode="wrap")
    def _serialize(self, handler):
        d = handler(self)
        d["resourceid"] = str(d["resourceid"])
        attributes = [
            {
                "name": "name",
                "value": self.name
            },
        ]
        for field_name in self.model_fields.keys():
            if d.get(field_name) is None:
                attributes.append(
                    {"name": field_name, "value": getattr(self, field_name)}
                )
        d["attributes"] = attributes

        return d

This implementation will add to the attributes all fields marked as exclude=True plus the name field