Bug: S3Model not compatible with ObjectRemoved events

Expected Behaviour

After deleting an object from S3, if a Lambda catches this event, they should be able to parse it. This event name from S3 is ObjectDeleted:*.

Current Behaviour

A ValidationError is thrown because of the missing size and eTag attributes.

Records -> 0 -> s3 -> object -> size
  field required (type=value_error.missing)
Records -> 0 -> s3 -> object -> eTag
  field required (type=value_error.missing)

The ObjectDeleted event does not include those attributes.

Code snippet

parse(model=S3Model, event=json.loads(s3_message))

Payload Example: https://github.com/awslabs/aws-lambda-powertools-python/issues/1637#issuecomment-1288170059

Possible Solution

Update S3Object so that both size and eTag are optional:

class S3Object(BaseModel):
    key: str
    size: Optional[NonNegativeFloat]
    eTag: Optional[str]
    sequencer: str
    versionId: Optional[str]

Steps to Reproduce

1. Create a Lambda function and an S3 bucket
2. Trigger the Lambda function through S3 events, and enable the ObjectDeleted type
3. Delete an object from S3
4. S3Model will raise a ValidationError

AWS Lambda Powertools for Python version

latest

AWS Lambda function runtime

3.8

Packaging format used

PyPi

Debugging logs

No response

[barreeeiroo]

@heitorlessa done, the PR should be available now: PR#1638. I couldn’t really test the change right now, but if strictly needed I can fully test it tomorrow.

[ran-isenberg]

@barreeeiroo yeah that makes sense! nice one. I’ll open a PR with tests in a few min.