Remote Kernel Gateways: Prompt for baseUrl

:memo: Summary

As a user trying to connect to a remote Jupyter kernel, I should have the option to supply the baseUrl for a new gateway (in addition to seeing the prexisting options I have supplied in the "gateways" section of the config).

:checkered_flag: Motivation

Many users create Jupyter kernels through jobs submitted to virtualized compute clusters. They do not control the IP address that is associated with the job/kernel. It may change every time they start/stop the job, possibly multiple times a day. Currently the config file json must be edited every time the user wishes to change the baseUrl for a remote kernel. This interface is tucked away in the package settings, and not conducive for repeated editing (raw json string in small text box).

:runner: Approach

I suspect all changes required would be confined to ws-kernel-picker.js. I can imagine the list of gateways would include an additional list item: "create gateway", which, upon selection, would prompt the user for a baseUrl, then possibly a token or cookie. Ideally, on subsequent creations, the previously entered fields would be remembered, to minimize the amount the user needs to edit.

:anchor: Drawbacks

I see no drawback other than the opportunity cost of development time.

:thinking: Alternatives

Currently one can work around this by creating some kind of localhost proxy, e.g. via ssh. But it is kind of hacky.

:question: Unresolved questions

The exact flow of how the user gets prompted (e.g. IP:port together or separate).
Whether / how to store the user's last input.

nteract / hydrogen