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
```
""" Return the string to be used for running Docker commands. """
        return config.DOCKER_CMD
    def prepare_event(self, environment, event_body):
        """ Return the event as a stdin string. """
        
        environment['AWS_LAMBDA_EVENT_BODY'] = event_body
        return None
    def _execute(self, func_arn, func_details, event, context=None, version=None):
        lambda_cwd = func_details.cwd
        runtime = func_details.runtime
        handler = func_details.handler
        environment = func_details.envvars.copy()
        
        if config.USE_SSL:
            environment['USE_SSL'] = '1'
        
        if not event:
            LOG.warning('Empty event body specified for invocation of Lambda "%s"' % func_arn)
            event = {}
        event_body = json.dumps(json_safe(event))
        stdin = self.prepare_event(environment, event_body)
        docker_host = config.DOCKER_HOST_FROM_CONTAINER
        environment['HOSTNAME'] = docker_host
        environment['LOCALSTACK_HOSTNAME'] = docker_host
        environment['_HANDLER'] = handler
        if func_details.timeout:
            environment['AWS_LAMBDA_FUNCTION_TIMEOUT'] = str(func_details.timeout)
        if context:
            environment['AWS_LAMBDA_FUNCTION_NAME'] = context.function_name