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
```
if not dlq_arn:
        return
    LOG.info('Sending failed execution %s to dead letter queue %s' % (source_arn, dlq_arn))
    message = json.dumps(event)
    message_attrs = {
        'RequestID': {'DataType': 'String', 'StringValue': str(uuid.uuid4())},
        'ErrorCode': {'DataType': 'String', 'StringValue': '200'},
        'ErrorMessage': {'DataType': 'String', 'StringValue': str(error)}
    }
    if ':sqs:' in dlq_arn:
        queue_url = aws_stack.get_sqs_queue_url(dlq_arn)
        sqs_client = aws_stack.connect_to_service('sqs')
        sqs_client.send_message(QueueUrl=queue_url, MessageBody=message, MessageAttributes=message_attrs)
    elif ':sns:' in dlq_arn:
        sns_client = aws_stack.connect_to_service('sns')
        sns_client.publish(TopicArn=dlq_arn, Message=message, MessageAttributes=message_attrs)
    else:
        LOG.warning('Unsupported dead letter queue type: %s' % dlq_arn)