Bug: Logger custom formatters not receiving standard keys

[heitorlessa]

Expected Behaviour

As per documentation, using a custom logging formatter should bring standard keys like service. Lambda context keys and custom keys are working just fine.

Example provided demonstrates that service key no longer appears in the first output.

Current Behaviour

When using a custom logging formatter, Powertools Logger standard keys are not being included.

This was identified when re-creating examples, outputs, and improving code snippets in #1262.

Code snippet

from aws_lambda_powertools import Logger
from aws_lambda_powertools.logging.formatter import LambdaPowertoolsFormatter


class CustomFormatter(LambdaPowertoolsFormatter):
    def serialize(self, log: dict) -> str:
        """Serialize final structured log dict to JSON str"""
        log["event"] = log.pop("message")  # rename message key to event
        return self.json_serializer(log)  # use configured json serializer


logger = Logger(service="payment", logger_formatter=CustomFormatter())
logger.info("hello")

logger_two = Logger(service="payment")
logger_two.info("hello")

Possible Solution

No response

Steps to Reproduce

Execute the code snippet locally, no need to deploy a Lambda function.

AWS Lambda Powertools for Python version

latest

AWS Lambda function runtime

3.9

Packaging format used

Lambda Layers

Debugging logs

No response

[heitorlessa]

This was introduced here when fixing clear_state: #1042

cc @jacobdarrossi @ilias-at-adarma for awareness, unless I misinterpret something

[heitorlessa]

Fix is up. I'll wait to hear from two customers familiar with the original change until next week before merging.

[github-actions]

This is now released under 1.26.3 version!