Description
Expected Behaviour
The expected behavior is that exceptions related to Powertools do not arise from the event_parser decorator in code like the following:
from aws_lambda_powertools.utilities.parser import event_parser
from pydantic import BaseModel
class EventModel(BaseModel):
"""It's just a sample, so the content can be anything."""
val: str
@event_parser(model=EventModel)
def lambda_handler(event: EventModel, context):
print(event) # correctly parsed
a = "aaa"
a.property # raise AttributeError (**NOT related to event_parser**)
# The following is intended for simple reproduction in a local environment:
if __name__ == "__main__":
lambda_handler({"val": "hello, lambda"}, None)Assume that the event is in a format that matches the EventModel by pydantic and is correctly parsed.
Therefore, the exception happening in the above code has nothing to do with powertools event_parser.
Current Behaviour
InvalidModelTypeError occurs within powertools, as shown below:
raise InvalidModelTypeError(f"Error: {str(exc)}. Please ensure the type you're trying to parse into is correct") aws_lambda_powertools.utilities.parser.exceptions.InvalidModelTypeError: Error: 'str' object has no attribute 'property'. Please ensure the type you're trying to parse into is correct
I consider it very confusing because even if the event validation in the event_parser decorator succeeds, the above exception is raised.
Code snippet
Same as described in “Expected Behaviour”.Possible Solution
Currently (v3.3.0), AttributeError is caught at the error location in powertools as follows:
Is it problematic to rewrite this part to catch Pydantic-derived Exceptions (e.g. pydantic.ValidationError) instead of AttributeError?
Steps to Reproduce
- Python version: 3.12
- architecture: x86_64
- The libraries used are the same versions as those installed by the following requirements.txt file:
# requirements.txt
annotated-types==0.7.0
aws-lambda-powertools==3.3.0
jmespath==1.0.1
pydantic==2.10.3
pydantic-core==2.27.1
typing-extensions==4.12.2Powertools for AWS Lambda (Python) version
3.3.0
AWS Lambda function runtime
3.12
Packaging format used
PyPi
Debugging logs
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