Feature request: support DynamoDB image values to dict with built-in Python types

Use case

When using DynamoDBRecord class, the values for old_image and new_image are represented as Dict[str, AttributeValue]. This representation is sufficient when the data parsed is simple and does not contain nested maps/lists. But when the data parsed contains nested maps/lists, then it becomes hard to get to the data that AttributeValue represents. One would need to recursively parse the AttributeValue objects in the nested dicts to get to the underlying data.

Solution/User Experience

Using a deserializer similar to the TypeDeserializer provided by boto3 (link to code), one would be able to convert image to a Python dict where the values would be built-in Python types.

Alternative solutions

No response

Acknowledgment

• This feature request meets Lambda Powertools Tenets
• Should this be considered in other Lambda Powertools languages? i.e. Java, TypeScript

[heitorlessa]

Released in V2 now 😉 https://github.com/awslabs/aws-lambda-powertools-python/releases/tag/v2.0.0

[shanab]

What about using boto3’s TypeDeserializer ?

That can be an option, but to my knowledge then one would not be able to do the following:

@event_source(data_class=DynamoDBStreamEvent)
def lambda_handler(event: DynamoDBStreamEvent, context):
    pass

because you’d need the raw Python dictionary for NewImage and OldImage to be able to use TypeDeserializer, and the event won’t expose that.