Error handling is STILL completely unreliable and unusable

[Cyberax]

Confirm by changing [ ] to [x] below to ensure that it's a bug:

• I've gone though the API reference
• I've checked AWS Forums and StackOverflow for answers
• I've searched for previous similar issues and didn't find any solution

Describe the bug
Error handling for S3 is unreliable and useless.

Version of AWS SDK for Go?
Example: v1.8.1

Version of Go (go version)?
1.16

To Reproduce (observed behavior)
Run GetBucketLocation on a non-existing bucket:

	output, err := s3Conn.GetBucketLocation(ctx, &s3.GetBucketLocationInput{
		Bucket: aws.String("DoesNotExist1231232113425"),
	})
	var errNoSuchBucket *s3types.NoSuchBucket
	if err != nil && errors.As(err, &errNoSuchBucket) {
		return err
	}
        panic("SHOULD HAVE WORKED")

Expected behavior
The error should have been properly interpreted.

Additional context
The generated deserializer is not even reached and doesn't have any provisions to deserialize NoSuchBucket errors: https://github.com/aws/aws-sdk-go-v2/blob/3ddb4d670277f173ec60e271ced9a07b605fbc0c/service/s3/deserializers.go#L3467

The only mentions of NoSuchBucket handling is in ListObjects and ListObjectsV2 error handling.

[KaibaLopez]

Hi @Cyberax ,
Sorry for the lack of response here, but yea I can reproduce the error. Thanks for bringing it up to us.

[MichaelCombs28]

This needs to be addressed for multiple services, not just s3.

[guseggert]

Given that AWS Go SDK V2 is GA now, is there a plan for fixing this while preserving backwards compat? This is a major shortcoming of V2 and I don't want my code to break when (if?) this is fixed, so I am inclined to stay on AWS Go SDK V1.

[Cyberax]

You can work around this issue by having a helper function to check the error codes. I've given up on waiting for AWS to fix this.

Here's my method:

type ErrCoder interface {
	ErrorCode() string
}

func CheckAwsError(err error, tgt ErrCoder) bool {
        if err == nil {
                return false;
        }
	var apiErr smithy.APIError
	if !errors.As(err, &apiErr) {
		return false
	}
	return apiErr.ErrorCode() == tgt.ErrorCode()
}

Using:

if CheckAwsError(err, &types.ConditionalCheckFailedException{}) { 
...
}

[itinance]

Thank you @Cyberax ! You saved my day :)

[yerke]

I am running into the same issue, but with DynamoDB APIs. It's a shame that this issue is not prioritized considering that this way of handling errors is suggested in migration guide.
Thanks to @Cyberax for figuring out a workaround.

[RanVaknin]

Hi @Cyberax and all.

Just to give an update. This is not GO SDK, or any AWS SDK specific issue. This is an S3 modeling issue that causes errors to not be mapped correctly from S3 to the respective SDKs.

This is still on the backlog, but requires the coordination of two major teams so takes time. I will raise this again with the service team in hopes that they can address it.

These two issues are somewhat related and stem from the same reason:
#63
#255

[RanVaknin]

@yerke ,

Dynamo's API shouldn't have this behavior. Please cut a separate, detailed ticket, with clear reproduction steps and I will address it.
Thanks you.

[yerke]

@RanVaknin Here you go: aws/aws-sdk-go-v2#1773. Thanks for looking into it.

[RanVaknin]

Created an internal ticket with the S3 team to add NoSuchBucket to the list of modeled errors for GetBucketLocation #P126361627.

Thanks,
Ran~