sqs.changeMessageVisibility according to [this](https://docs.aws.amazon.com/AWSSimpleQueueService/latest/APIReference/API_ChangeMessageVisibility.html#API_ChangeMessageVisibility_Examples) makes a request directly to the Queue's URL rather than via the SQS Endpoint. (I'm already setting SQS endpoint to LOCALSTACK_HOSTNAME - makes no difference for this call)..

In localstack the queue URL host returned is by default set to the value of HOSTNAME_EXTERNAL, which I'm setting to localstack, but calling this method within a lambda, does not work and I get the error:

```
UnknownEndpoint: Inaccessible host: `localstack'. This service may not be available in the `us-east-1' region. 
```

So, how can I make the queue URL accessible from within a lambda using localstack? Effectively I need to make **http://localstack** accessible from within lambda.

I'm using the following cmd to start localstack:

```
LAMBDA_EXECUTOR=docker-reuse DEBUG=1 LAMBDA_REMOTE_DOCKER=0 DATA_DIR=/tmp/localstack/data HOSTNAME_EXTERNAL=localstack localstack start
```
def is_s3_copy_request(self, headers, path):
        return 'x-amz-copy-source' in headers or 'x-amz-copy-source' in path
    def forward_request(self, method, path, data, headers):
        
        parsed_path = urlparse.urlparse(path)
        
        
        if 's3.amazonaws.com' not in headers.get('host', ''):
            headers['host'] = 'localhost'
        
        if 'Content-MD5' in headers and not self.is_s3_copy_request(headers, path):
            response = check_content_md5(data, headers)
            if response is not None:
                return response
        modified_data = None
        
        bucket_name = get_bucket_name(path, headers)
        if method == 'PUT' and not re.match(BUCKET_NAME_REGEX, bucket_name):
            if len(parsed_path.path) <= 1:
                return error_response('Unable to extract valid bucket name. Please ensure that your AWS SDK is ' +
                    'configured to use path style addressing, or send a valid <Bucket>.s3.amazonaws.com "Host" header',
                    'InvalidBucketName', status_code=400)
            return error_response('The specified bucket is not valid.', 'InvalidBucketName', status_code=400)
        
        to_find = to_bytes('<LocationConstraint>us-east-1</LocationConstraint>')
        if data and data.startswith(to_bytes('<')) and to_find in data:
            modified_data = data.replace(to_find, to_bytes(''))