@Marvin can i set a default text into my dict in the Field?

To assist you better, I'll need to confirm which version of Prefect you are using, as the approach to setting default values in fields might differ between Prefect 2.x and Prefect 3.x. If you know which version you're using, please let me know! Otherwise, I can provide information for both versions, or guide you through any steps to find out.

@Marvin im using prefect 2

In Prefect 2, you can define default values within a custom block field using Pydantic models. You define default values for fields by assigning them in the class definition of your

Block

. This is illustrated in the example below:

python
from typing import Optional
from prefect.blocks.core import Block

class MyConfig(Block):
    my_default_field: Optional[str] = "default text"
    another_field: Optional[str] = None

# Usage
config = MyConfig()
print(config.my_default_field)  # Output: "default text"

In this example, the field

my_default_field

is set with a default value of "default text". When you create an instance of

MyConfig

and don't provide a value for

my_default_field

, it defaults to this text. You can find more details on how to define custom blocks and fields in the Prefect 2 documentation on Blocks. Let me know if you need further assistance!

hi @Kamilly Victória Ruseler - i might be in a better position to help with pydantic questions if you're asking about

Field

from pydantic?

yess, @Nate. i've missed you, by the way haha.

🙂 can you expand on this a little?

can i set a default text into my dict in the Field?

you can set default values for fields in 1 of 2 main ways • the

default

kwarg

class Foo(BaseModel):
  d: dict = Field(default=dict(some_key=42))

• default factories (a function that returns your default)

class Foo(BaseModel):
  d: dict = Field(default_factory=lambda: dict(some_key=42))

if this is not what you're trying to do, please feel free to give a small example!

yeah! i was doing like this: hyperparams: Optional[Dict[str, Any]] = Field( default_factory=lambda: { "objective": "", "boosting": "", "num_iterations": [], "learning_rate": [], "num_leaves": [], "max_depth": [], "bagging_fraction": [], "lambda_l1": [], "lambda_l2": [], } ) i followed your example using default instead of default_factory and it worked! thank you so much, again. for the 10000th time hahah

no problem! just a pedantic note that you might already know, but just in case you don't: counterintuitively,

Optional

tells pydantic that "`None` is a valid value for `hyperparams`" i.e.

Optional

does not exactly mean that a user can "optionally" pass the value of

hyperparams

so if you just want

hyperparams

to be a

dict

that defaults to the return of your lambda, you would have

class Model(BaseModel):
  hyperparams: Dict[str, Any] = Field(default_factory=lambda: dict(...))

thank you, nate! also, i have another doubt. when i go to the "Use json input" section, my hyperparams field receives a "prefect_kind" parameter. why does it happen? "hyperparams": { "value": "{\n \"lgbm\": {\n}", "__prefect_kind": "json" },