stepfunctions: support dynamic bucket in Map ItemReader

[gael-ft]

Describe the feature

Goal is to allow using JsonPath for IItemReader properties when defining a Map.

For now, interface IItemReader defines bucket field as type IBucket.

But from a CFN perspective we only need a bucket name.
Using IBucket blocks users from using JsonPath as dynamic bucket name.

Example:

const distributedMap = new sfn.DistributedMap(this, 'Distributed Map State', {
  itemReader: new sfn.S3JsonItemReader({
    bucket: JsonPath.stringAt('$.myBucket'),
    key: JsonPath.stringAt('$.myKey'),
  }),
  // ...
});

"ItemReader": {
    "Resource": "arn:aws:states:::s3:getObject",
    "ReaderConfig": {
        "InputType": "JSON"
    },
    "Parameters": {
        "Bucket.$": "$.myBucket",
        "Key.$": "$.myKey"
    }
}

Current CDK implementation

Use Case

Using the provided construct instead of a CustomState for DistributedMap.

Proposed Solution

Simply using string instead of IBucket (possibly accepting both if necessary ?)

Other Information

No response

Acknowledgements

• I may be able to implement this feature request
• This feature might incur a breaking change

CDK version used

2.162.1

Environment details (OS name and version, etc.)

macOS 13.5

[khushail]

Hi @gael-ft , thanks for reaching out.

I found a previous similar issue reg the support of Dynamic bucket in Map ItemReader - #29409 and PR seems to be merged 4 days ago -#31619

Please let me know if that works as per your usecase.