Hi all, Has anyone tried to download file from S3 which is encrypted using KMS key via http_source as enabled by the backend

pants.backend.url_handlers.s3

? Sample code being :

file(
    name="test-download",
    source=http_source(url="<s3://example-bucket/bucket-data.gz>",
                       sha256="20ee0c788011355604f31e41b2ec87d718da588d7404b9bbb50",
                       len=740199)
)

Currently it fails with a 400 error because

Requests specifying Server Side Encryption with AWS KMS managed keys require AWS Signature Version 4.

whereas we dont use SigV4Auth currently in pants code Now when I tried to use SigV4Auth (ie AWS Signature Version 4) method as available in botocore here , it is still failing with 403 errors. For debugging I printed all the headers passed for the request. And tried to make the same request using python like following

resp = requests.get(url = url, headers = headers)

The weird thing is the python request gets a 200 response while the equivalent pants one gets a 403 response. Any help is much appreciated, as always. Thank you!