Connecting to server from notebooks-ui during spawn results in 500 about renku-notebooks HOT 9 CLOSED

[2018-09-07 05:29:46 +0000] [8] [ERROR] Error handling request /jupyterhub/services/notebooks/eberlej/test-renku/b408a9cd335cb122eef4ae3bc0507f19c9ae6905/test.ipynb
Traceback (most recent call last):
  File "/usr/local/lib/python3.6/site-packages/gunicorn/workers/base_async.py", line 56, in handle
    self.handle_request(listener_name, req, client, addr)
  File "/usr/local/lib/python3.6/site-packages/gunicorn/workers/ggevent.py", line 160, in handle_request
    addr)
  File "/usr/local/lib/python3.6/site-packages/gunicorn/workers/base_async.py", line 107, in handle_request
    respiter = self.wsgi(environ, resp.start_response)
  File "/usr/local/lib/python3.6/site-packages/flask/app.py", line 2309, in __call__
    return self.wsgi_app(environ, start_response)
  File "/app/src/notebooks_service.py", line 91, in __call__
    return self.app(environ, start_response)
  File "/usr/local/lib/python3.6/site-packages/flask/app.py", line 2295, in wsgi_app
    response = self.handle_exception(e)
  File "/usr/local/lib/python3.6/site-packages/flask/app.py", line 1741, in handle_exception
    reraise(exc_type, exc_value, tb)
  File "/usr/local/lib/python3.6/site-packages/flask/_compat.py", line 35, in reraise
    raise value
  File "/usr/local/lib/python3.6/site-packages/flask/app.py", line 2292, in wsgi_app
    response = self.full_dispatch_request()
  File "/usr/local/lib/python3.6/site-packages/flask/app.py", line 1815, in full_dispatch_request
    rv = self.handle_user_exception(e)
  File "/usr/local/lib/python3.6/site-packages/flask/app.py", line 1718, in handle_user_exception
    reraise(exc_type, exc_value, tb)
  File "/usr/local/lib/python3.6/site-packages/flask/_compat.py", line 35, in reraise
    raise value
  File "/usr/local/lib/python3.6/site-packages/flask/app.py", line 1813, in full_dispatch_request
    rv = self.dispatch_request()
  File "/usr/local/lib/python3.6/site-packages/flask/app.py", line 1799, in dispatch_request
    return self.view_functions[rule.endpoint](**req.view_args)
  File "/app/src/notebooks_service.py", line 136, in decorated
    return f(user, *args, **kwargs)
  File "/app/src/notebooks_service.py", line 233, in notebook_status
    app.logger.debug(request.environ['HTTP_REFERER'])
KeyError: 'HTTP_REFERER'

[I 2018-09-07 08:22:49.155 JupyterHub log:158] 302 GET /jupyterhub/user/rokroskar/rokroskar-test-567e45d/ -> /jupyterhub/hub/user/rokroskar/rokroskar-test-567e45d/ (@10.39.0.0) 1.25ms
[D 2018-09-07 08:22:49.203 JupyterHub base:603] Initiating spawn for rokroskar
[D 2018-09-07 08:22:49.203 JupyterHub base:609] 1/64 concurrent spawns
[D 2018-09-07 08:22:49.203 JupyterHub base:612] 1 active servers
[I 2018-09-07 08:22:49.282 JupyterHub spawners:84] starting with args: --ip="0.0.0.0" --port=8888 --notebook-dir="/home/jovyan/work" --NotebookApp.default_url="/lab" --debug
[D 2018-09-07 08:22:49.282 JupyterHub spawners:86] user options: {}

[D 2018-09-07 08:22:46.157 JupyterHub spawners:86] user options: {'branch': 'master', 'commit_sha': '567e45df39ce2c5ce044339887a8b5fc67eea007', 'namespace': 'rokroskar', 'notebook': None, 'project': 'test', 'image_pull_secrets': ['renku-notebooks-registry']}