S3 list-directory-buckets fails with `Could not connect to the endpoint URL` when used in unsupported regions

[oleksii-k-amzn]

Describe the bug

When used in unsupported regions for S3 Express One (for example eu-central-1) Boto3 fails with

File "/opt/amazon/lib/python3.10/site-packages/botocore/httpsession.py", line 494, in send
    raise EndpointConnectionError(endpoint_url=request.url, error=e)
botocore.exceptions.EndpointConnectionError: Could not connect to the endpoint URL: "https://s3express-control.eu-central-1.amazonaws.com/

instead of telling to the customer that the region is not supported for this API

Regression Issue

• Select this option if this issue appears to be a regression.

Expected Behavior

Instead of timeout exception there should be some other exception thrown that would inform the user about endpoint availability.

Current Behavior

Timeout exception is thrown when used with the region that does not support S3 Express One

File "/opt/amazon/lib/python3.10/site-packages/botocore/httpsession.py", line 494, in send
    raise EndpointConnectionError(endpoint_url=request.url, error=e)
botocore.exceptions.EndpointConnectionError: Could not connect to the endpoint URL: "https://s3express-control.eu-central-1.amazonaws.com/

Reproduction Steps

Use Boto3 to call S3.Client.list_directory_buckets(...) in eu-central-1

https://boto3.amazonaws.com/v1/documentation/api/latest/reference/services/s3/client/list_directory_buckets.html

Possible Solution

Add S3 Express One regions check and throw proper error

Additional Information/Context

No response

SDK version used

1.42.3

Environment details (OS name and version, etc.)

Running within docker container that uses 137112412989.dkr.ecr.us-west-2.amazonaws.com/amazonlinux@sha256:609328a448f9b1e198785bc2574f4b047d9a3b9542bb5a31fcfaeb9903756201 . Container is running within MDE(ECS)

[adev-code]

Hello @oleksii-k-amzn, thanks for reaching out. Boto3 tries to connect to an endpoint either from the API service request default or a custom endpoint. Custom endpoints can point to any URL, and the SDK doesn't know in advance which endpoint the user will provide. For a custom error message to be returned, the service itself has to return that error—but to reach the AWS service, the SDK needs to connect to a service endpoint first. In this case, the region may not be available yet as per the S3 Express endpoint documentation.

I've reached out to the service team for a feature request to add the region eu-central-1. We don't have a timeline yet on when/if the service is going to release this. Moving forward, please see changelogs (Botocore and Boto3) for updates from the S3 team.

Internal Ref: P358770099

[github-actions]

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