text: # Copyright (c) Jupyter Development Team.
  # Distributed under the terms of the Modified BSD License.
  
  # Configuration file for JupyterHub
  import os
  
  c = get_config()  # noqa
  
  # We rely on environment variables to configure JupyterHub so that we
  # avoid having to rebuild the JupyterHub container every time we change a
  # configuration parameter.
  
  # Spawn single-user servers as Docker containers
  c.JupyterHub.spawner_class = 'dockerspawner.DockerSpawner'
  # Spawn containers from this image
  c.DockerSpawner.container_image = os.environ['DOCKER_NOTEBOOK_IMAGE']
  # JupyterHub requires a single-user instance of the Notebook server, so we
  # default to using the `start-singleuser.sh` script included in the
  # jupyter/docker-stacks *-notebook images as the Docker run command when
  # spawning containers.  Optionally, you can override the Docker run command
  # using the DOCKER_SPAWN_CMD environment variable.
  spawn_cmd = os.environ.get('DOCKER_SPAWN_CMD', "start-singleuser.sh")
  c.DockerSpawner.extra_create_kwargs.update({'command': spawn_cmd})
  # Connect containers to this Docker network
  network_name = os.environ['DOCKER_NETWORK_NAME'] or 'default'
  c.DockerSpawner.use_internal_ip = True
  c.DockerSpawner.network_name = network_name
  # Pass the network name as argument to spawned containers
  c.DockerSpawner.extra_host_config = {'network_mode': network_name}
  # Explicitly set notebook directory because we'll be mounting a host volume to
  # it.  Most jupyter/docker-stacks *-notebook images run the Notebook server as
  # user `jovyan`, and set the notebook directory to `/home/jovyan/work`.
  # We follow the same convention.
  notebook_dir = os.environ.get('DOCKER_NOTEBOOK_DIR') or '/data/notebooks'
  c.DockerSpawner.notebook_dir = notebook_dir
  # Mount the real user's Docker volume on the host to the notebook user's
  # notebook directory in the container
  c.DockerSpawner.volumes = {'jupyterhub-user-{username}': notebook_dir}
  c.DockerSpawner.extra_create_kwargs.update({'volume_driver': 'local'})
  # Remove containers once they are stopped
  c.DockerSpawner.remove_containers = True
  # For debugging arguments passed to spawned containers
  c.DockerSpawner.debug = True
  
  # User containers will access hub by container name on the Docker network
  # c.JupyterHub.hub_ip = 'jupyterhub'
  c.JupyterHub.hub_ip = '0.0.0.0'
  c.JupyterHub.hub_port = 8080
  
  # TLS config
  c.JupyterHub.port = 443
  c.JupyterHub.ssl_key = os.environ['SSL_KEY']
  c.JupyterHub.ssl_cert = os.environ['SSL_CERT']
  
  # Authenticate users with GitHub OAuth
  if os.getenv("GITHUB_AUTH_ENABLED", "0") == "1":
      c.JupyterHub.authenticator_class = 'oauthenticator.GitHubOAuthenticator'
      c.GitHubOAuthenticator.oauth_callback_url = os.environ['OAUTH_CALLBACK_URL']
  
  # Persist hub data on volume mounted inside container
  data_dir = os.environ.get('DATA_VOLUME_CONTAINER', '/data')
  
  c.JupyterHub.cookie_secret_file = os.path.join(data_dir, 'jupyterhub_cookie_secret')
  
  c.JupyterHub.db_url = 'postgresql://postgres:{password}@{host}/{db}'.format(
      host=os.environ['POSTGRES_HOST'],
      password=os.environ['POSTGRES_PASSWORD'],
      db=os.environ['POSTGRES_DB'],
  )
  
  # Whitlelist users and admins
  c.Authenticator.whitelist = whitelist = set()
  c.Authenticator.admin_users = admin = set()
  c.JupyterHub.admin_access = True
  pwd = os.path.dirname(__file__)
  
  user_list_file = os.getenv("USERLIST_FILE",
                             "/files/jupyter_userlist")
  
  if os.path.exists(user_list_file):
      print("Loading user_list_file={}".format(user_list_file))
      with open(user_list_file) as f:
          for line in f:
              if not line:
                  continue
              parts = line.split()
              name = parts[0]
              whitelist.add(name)
              if len(parts) > 1 and parts[1] == 'admin':
                  admin.add(name)
  