Gateway clusters can have different public URL and private URL

[minrk]

Describe the issue:

I am using dask-labextension with Dask Gateway in JupyterHub. The dask gateway dashboard proxy is exposed through an oauth proxy at a public URL. The jupyter-server can talk directly to the proxy service endpoint without auth.

e.g.

• from outside: https://hub.host/services/auth-proxy/dask-gateway/name.uuid/status (needs oauth)
• from jupyter-server: http://traefik-dask-gateway/name.uuid/status (no auth)

which leads to:

• jupyter-server cannot talk to the public endpoint because it can't execute oauth.
• browsers cannot talk to the internal endpoint, because it's not a public URL

As a result, the dashboard link in the UI needs to be the public one and the dashboard URL needs to be the proxy one.

I believe it would work if I could tell the labextension dashboard to talk directly to the dashboard URL (no proxy request at all), instead of unconditionally proxying through the extension. I'm not sure of the best way to indicate that, though.

Anything else we need to know?:

Environment:

• Dask version: 2025.1 (labextension 7.0.0)
• Python version: 3.11
• Operating System: linux
• Install method (conda, pip, source): conda