adding options to run notebook with kernel gateway

[shiti-saxena]

resolves #3005

[minrk]

Thanks! I think this mostly makes sense, but special-casing kernel handlers doesn't seem quite right. What about sessions etc.?

Maybe there should be a generic handlers-overrides mechanism that would allow overriding any handlers?

Thanks to the load_handlers mechanism, this could be a list of modules, e.g. extra_services to be loaded that are ensured to be loaded at higher priority to the default services.

What do you think?

[minrk]

nit: singluar 'kernelspec_handlers' to match 'kernel_handlers'

[shiti-saxena]

@minrk It is possible to modify the load_handlers method to allow overriding any handler as currently it adds notebook. prefix. But I wasn't sure if we would want to expose that to users. Should I update the PR to do that as well?

[parente]

I agree with @minrk here. Overriding the kernel handler and kernel manager handler was the only requirement for the nb2kg demo. Making the overrides general purpose seems more appropriate for a notebook server feature.

Did not mean to request changes, only comment. Trying again!

[shiti-saxena]

@minrk @parente I've created another PR #3158 based on the feedback and comments, what do you think of it?

[takluyver]

Closing for now in favour of #3158