s3 presigned request does not work with custom endpoint and no region set

[ibotty]

If using an aws-config with custom endpoint, but no region the presigned request is not complete. If setting the region it works allright.

Is that expected? If so it would be great to at least document it or better statically prohibit using it without region.

let aws_config = aws_config::from_env()
    .endpoint_url(...)
    //.region("us-east-1")
    .load()
    .await;
let client = aws_sdk_s3::Client::from_conf(s3_config);
let req = client.get_object()
    .bucket(..)
    .key("test-key")
    .presigned(..)
    .await.unwrap();
assert_eq(req.uri, "/test-key/?x-id=GetObject")

[rcoh]

signing requires a region as an inherent part of signing, so any request needs a region. Unfortunately, there isn't a practical way to prohibit this statically, since, e.g. a region could be set as late as config override when customizing the request.