Support using remote kernels

[nbren12]

I usually have ipython notebook running on a remote server, which I then connect to over ssh using port forwarding. These are the commands I usually run.

ssh -L 8888:127.0.0.1:8888 myserver
ipython notebook --port 8888 --no-browser

Then, I open 127.0.0.1:8888 in the browser on my local machine. Is there an easy way to do this sort of workflow in ob-ipython?

[gregsexton]

This should be very easy to support. Currently emacs starts the ipython kernel for you and a process which assumes that it is local. When I get time I'll take a look at opening up customisation here to allow running remotely.

[smartass101]

I think this use case could be simply achieved by setting

(setq ob-ipython-driver-port 8888)

after creating the tunnel.
If you want this to be the case only for a given buffer, use setq-local instead.

If you don't want to use the intermediary tunnel, you'd have appply the changes proposed in my PR #29.

However, I think a more flexible approach would be to implement something like an :address header argument or :hostname and :port arguments and these settings would only serve as default settings. This should be reflected by e.g. renaming the to *-default*-.

On a different note, I think a different Customize group (Org Babel IPython) might be more appropriate to make ti easier for the user to find these setting in the group that would logically fit into the hierarchy.

[gregsexton]

I've merged the PR allowing for connecting to a different hostname across all src blocks. Leaving this open to implement the :hostname and :port arguments as suggested. Great idea.

[smartass101]

I have a working prototype of a solution in PR #39, but please note that at the moment it requires fix for bug in jupyter_client, see the PR for details. It works quite well.