What's the usage or advantages on using aws_lambda_powertools.utilities.parser parse?

[jerry118118]

As I am new to lambda, I am wondering should I use aws_lambda_powertools.utilities.parser parse?

I wrote a simple test and didn't find any differences between unpacking and parse. In what cases should I use parse, grateful if someone can share their usages or experiences. Thanks a lot!

class User(BaseModel):
    id: str
    user_name: str

user = {
    'id': '1',
    'user_name': 'alice'
}

userUnpack = User(**user)
userParse = parse(model=User, event=user)

[leandrodamascena]

Hi @jerry118118! Glad to hear you're considering using Powertools!

In this use case you're right, there's not much difference between using parser and validating it directly against the Pydantic model, both work basically the same way. We try to optimize the experience by caching the model and not trying to load it into memory all the time, but this is useful if you have thousands of validations, which doesn't seem to be your case.

Another use case we help customers with using the Parser utility is the ability to fail fast by using the event_parser function and decorating your Lambda handler. In this case if the event doesn’t match the Model it will fail before executing the Lambda handler, which can prevent issues in your code.

Another use case is when you want to extract the envelope of your events, I mean the part that contains the actual data. You can extract the part that only matters to you and discard the rest of the information.

Please let me know if this explanation helps you in adopting Powertools for AWS Lambda (Python).

Thanks

[jerry118118]

Hi @leandrodamascena, thanks for your detailed explaination. As in my case, my Pydantic model is pretty simple which invovle a few validation only. In that case, I guess I can stick to the unpack way.

I will definitely look into event_parser and envelope in the future if needed. Thanks again!