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
```
""" List functions
        ---
        operationId: 'listFunctions'
        parameters:
            - name: 'request'
              in: body
    """
    funcs = do_list_functions()
    result = {}
    result['Functions'] = funcs
    return jsonify(result)
@app.route('%s/functions/<function>' % PATH_ROOT, methods=['DELETE'])
def delete_function(function):
    """ Delete an existing function
        ---
        operationId: 'deleteFunction'
        parameters:
            - name: 'request'
              in: body
    """
    arn = func_arn(function)