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
```
sources = get_event_sources(source_arn=queue_arn)
        arns = [s.get('FunctionArn') for s in sources]
        LOG.debug('Found %s source mappings for event from SQS queue %s: %s' % (len(arns), queue_arn, arns))
        source = next(iter(sources), None)
        if not source:
            return False
        if source:
            arn = source['FunctionArn']
            event = {'Records': [{
                'body': message_body,
                'receiptHandle': short_uid(),
                'md5OfBody': md5(message_body),
                'eventSourceARN': queue_arn,
                'eventSource': 'aws:sqs',
                'awsRegion': region_name,
                'messageId': str(uuid.uuid4()),
                'attributes': {
                    'ApproximateFirstReceiveTimestamp': '{}000'.format(int(time.time())),
                    'SenderId': TEST_AWS_ACCOUNT_ID,
                    'ApproximateReceiveCount': '1',
                    'SentTimestamp': '{}000'.format(int(time.time()))
                },
                'messageAttributes': message_attributes,
                'sqs': True,
            }]}
            run_lambda(event=event, context={}, func_arn=arn, asynchronous=True)
            return True
    except Exception as e:
        LOG.warning('Unable to run Lambda function on SQS messages: %s %s' % (e, traceback.format_exc()))
def get_event_sources(func_name=None, source_arn=None):