type AmazonWrapperInterface interface {
    ListS3() []string
    EC2Create(string) bool
}

type amazonWrapperImpl struct {
    aws *aws.S3
}

func NewAmazonWrapper() AmazonWrapperInterface {
    // implement configuration here etc
    return &amazonWrapperImpl{}
}

func (a *amazonWrapperImpl) ListS3() []string {
    return a.aws.ListS3()
}