Any way to default initialize protobuf message type fields?

[mjkmj]

I've tried to figure out a way to default initialize fields that are of protobuf message type.

Example:

syntax = "proto3";
package example;

message MyMessage1
{
    optional string content = 1;
}

message MyMessage2
{
    optional MyMessage1 my_message = 1;
}

Output of protobuf_to_pydantic would be:

from google.protobuf.message import Message  # type: ignore
from pydantic import BaseModel
from pydantic import Field
import typing


class MyMessage1(BaseModel):
    content: typing.Optional[str] = Field(default="")

class MyMessage2(BaseModel):
    my_message: typing.Optional[MyMessage1] = Field(default=None)

Desired output would be:

from google.protobuf.message import Message  # type: ignore
from pydantic import BaseModel
from pydantic import Field
import typing


class MyMessage1(BaseModel):
    content: typing.Optional[str] = Field(default="")

class MyMessage2(BaseModel):
    my_message: typing.Optional[MyMessage1] = Field(default=MyMessage1())

(The key change here is the default value of the my_message field in MyMessage2 class)

Is there a way to achieve this kind of behaviour?
(BTW I think that protobuf handles its protobuf message fields that way, but I'm not sure)

[mjkmj]

@so1n Any idea? :)

[so1n]

@so1n Any idea? :)

@mjkmj I'm working on this issue, the new version will generate the following code:

from google.protobuf.message import Message  # type: ignore
from pydantic import BaseModel
from pydantic import Field
import typing


class MyMessage1(BaseModel):
    content: typing.Optional[str] = Field(default="")

class MyMessage2(BaseModel):
    my_message: typing.Optional[MyMessage1] = Field(default=MyMessage1())

[so1n]

@mjkmj Version 0.3.1.0 containing the fix for this issue has been released

[ShaneMurphy2]

@so1n Is there a way to preserve the default of None behavior?

[so1n]

@ShaneMurphy2
Starting from version 0.3.1.1, you can specify the default value None , for example protobuf:

syntax = "proto3";
package example;

// import your p2p_validate.proto

message MyMessage1
{
    optional string content = 1;
}

message MyMessage2
{
    optional MyMessage1 my_message_1 = 1;
    optional MyMessage1 my_message_2 = 2[(p2p_validate.rules).message.default_template="p2p@builtin|None"];  // <----- change 
}

According to the above rules, the generated default value will become None:

import typing

from google.protobuf.message import Message  # type: ignore
from pydantic import BaseModel, Field


class MyMessage1(BaseModel):
    content: typing.Optional[str] = Field(default="")


class MyMessage2(BaseModel):
    my_message_1: typing.Optional[MyMessage1] = Field(default_factory=MyMessage1)
    my_message_2: typing.Optional[MyMessage1] = Field(default=None)   # <---- change

[plsmaop]

Hi @so1n

optional MyMessage1 my_message_2 = 2[(p2p_validate.rules).message.default_template="p2p@builtin|None"];

Anyway to configure this in code for runtime mode ?

[so1n]

Yes, Some default behaviors can only be changed through rule

[plsmaop]

Thx @so1n ,

Could you give me some example because I do not know how to set rule usign msg_to_pydantic_model

[so1n]

@plsmaop
rule documentation: https://github.com/so1n/protobuf_to_pydantic?tab=readme-ov-file#2parameter-validation
rule example:

• https://github.com/so1n/protobuf_to_pydantic/blob/master/example/example_proto/p2p_validate/demo.proto
  -https://github.com/so1n/protobuf_to_pydantic/blob/master/example/example_proto/p2p_validate_by_comment/demo.proto