After cloning the repo and running: `docker build -t localstack:latest .`
I can see the following errors:

```
Starting mock Lambda service (http port 4574)...
ERROR: Error forwarding request: HTTPConnectionPool(host='127.0.0.1', port=4564): Max retries exceeded with url: / (Caused by NewConnectionError('<urllib3.connection.HTTPConnection object at 0x7f4c7b4e7c10>: Failed to establish a new connection: [Errno 111] Connection refused',)) Traceback (most recent call last):
  File "/opt/code/localstack/localstack/services/generic_proxy.py", line 216, in forward
    headers=forward_headers, stream=True)
  File "/opt/code/localstack/.venv/lib/python2.7/site-packages/requests/api.py", line 116, in post
    return request('post', url, data=data, json=json, **kwargs)
  File "/opt/code/localstack/.venv/lib/python2.7/site-packages/requests/api.py", line 60, in request
    return session.request(method=method, url=url, **kwargs)
  File "/opt/code/localstack/.venv/lib/python2.7/site-packages/requests/sessions.py", line 524, in request
    resp = self.send(prep, **send_kwargs)
  File "/opt/code/localstack/.venv/lib/python2.7/site-packages/requests/sessions.py", line 637, in send
    r = adapter.send(request, **kwargs)
  File "/opt/code/localstack/.venv/lib/python2.7/site-packages/requests/adapters.py", line 516, in send
    raise ConnectionError(e, request=request)
ConnectionError: HTTPConnectionPool(host='127.0.0.1', port=4564): Max retries exceeded with url: / (Caused by NewConnectionError('<urllib3.connection.HTTPConnection object at 0x7f4c7b4e7c10>: Failed to establish a new connection: [Errno 111] Connection refused',))
```

I see the same thing when running `localstack start --docker` which is what I originally tried as I would like to use localstack for development purposes in an existing stack.

MacOS Mojave 10.14
Docker for Mac: 18.06.1-ce-mac73 (26764)
custom_backend_url = os.environ.get('%s_BACKEND' % service_name.upper())
    backend_url = custom_backend_url or ('http://%s:%s' % (DEFAULT_BACKEND_HOST, default_backend_port))
    return start_proxy(port, backend_url=backend_url, update_listener=update_listener, quiet=quiet, params=params)
def start_proxy(port, backend_url, update_listener, quiet=False, params={}):
    proxy_thread = GenericProxy(port=port, forward_url=backend_url,
        ssl=USE_SSL, update_listener=update_listener, quiet=quiet, params=params)
    proxy_thread.start()
    TMP_THREADS.append(proxy_thread)
    return proxy_thread
def start_moto_server(key, port, name=None, backend_port=None, asynchronous=False, update_listener=None):
    moto_server_cmd = '%s/bin/moto_server' % LOCALSTACK_VENV_FOLDER
    if not os.path.exists(moto_server_cmd):
        moto_server_cmd = run('which moto_server').strip()
    cmd = 'VALIDATE_LAMBDA_S3=0 %s %s -p %s -H %s' % (moto_server_cmd, key, backend_port or port, constants.BIND_HOST)
    if not name:
        name = key
    print('Starting mock %s (%s port %s)...' % (name, get_service_protocol(), port))
    if backend_port:
        start_proxy_for_service(key, port, backend_port, update_listener)
    elif USE_SSL:
        cmd += ' --ssl'
    return do_run(cmd, asynchronous)
def start_local_api(name, port, method, asynchronous=False):