Accessing MyBinder Kernels Remotely from IPython Magic and from VS Code

One of the issues facing us as a distance learning organisation is how to support the computing needs of distance learning students, on a cross-platform basis, and over a wide range of computer specifications.

The approach we have taken for our TM351 Data Management and Analysis course is to ship students a Virtualbox virtual machine. This mostly works. But in some cases it doesn’t. So in the absence of an institutional online hosted notebook, I started wondering about whether we could freeload on MyBinder as a way of helping students run the course software.

I’ve started working on an image here though it’s still divergent from the shipped VM (I need to sort out things like database seeding, and maybe fix some of the package versions…), but that leaves open the question of how students would then access the environment.

One solution would be to let students work on MyBinder directly, but this raises the question of how to get the course notebooks into the Binder environment (the notebooks are in a repo, but its a private repo) and out again at the end of a session. One solution might be to use a Jupyter github extension but this would require students setting up a Github repository, installing and configuring the extension, remember to sync (unless auto-save-and-commit is available, or could be added to the extendion) and so on…

An alternative solution would be to find a way of treating MyBinder like an Enterprise Gateway server, launching a kernel via MyBinder from a local notebook server extension. But I don’t know how to do that.

Some fragments I have had laying around for a bit were the first fumblings towards a Python Mybinder client API, based on the Sage Cell client for running a chunk of code on a remote server… So I wondered whether I could do another pass over that code to ceate some IPython magic that let you create a MyBinder environment from a repo and then execute code against it from a magicked code cell. Proof of concept code for that is here: innovationOUtside/ipython_binder_magic.

One problem is that the connection seems to time out quite quickly. The code is really hacky and could probably be rebuilt from functions in the Jupyter client package, but making sense of that code is beyond my limited cut-and-paste abilities. But: it does offer a minimal working demo of what such a thing could be like. At a push, a student could install a minimal Jupyter server on their machine, install the magic, and then write notebooks using magic to run the code against a Binder kernel, albeit one that keeps dying. Whilst this would be inconvenient, it’s not a complete catastrophe because the notebook would be bing saved to the student’s local machine.

Another alternative struck me today when I say that Yuvi Panda had posted to the official Jupyter blog a recipe on how to connect to a remote Jupyterhub from Visual Studio Code. The mechanics are quite simple — I posted a demo here about how to connect from VS Code to a remote Jupyter server running on Digital Ocean, and the same approach works for connecting to out VM notebook server, if you tweak the VM notebook server’s access permissions — but it requires you to have a token. Yuvi’s post says how to find that from a remote JupyterHub server, but can we find the token for a MyBinder server?

If you open your browser’s developer tools and watch the network traffic as you launch a MyBinder server, then you can indeed see the URL used to launch the environment, along with the necessary token:

But that’s a bit of a faff if we want students to launch a Binder environment, watch the newtrok traff, grab the token and then use that to create a connection to the Binder environment from VS Code.

Searching the contents of pages from a running Binder environment, it seems that the token is hidden in the page:

And it’s not that hard to find… it’s in the link from the Jupyter log. The URL needs a tiny bit of editing (cut the /tree path element) but then the URL is good to go as the kernel connection URL in VS Code:

Then you can start working on your notebook in VS Code (open a new notebook from the settings menu), executing the code against the MyBinder environment.

You can also see the notebooks listed in the remote MyBinder environment.

So that’s another way… and now it’s got me thinking… how hard would it be to write a VS Code extension to launch a MyBinder container and then connect to it?

Ps by the by, I notice that developer tools in Firefox become increasingly useful with the Firefox 71 release in the form of a websocket inspector.

This lets you inspect traffic sent across a webseocket connection. For example, if we force a page reload on a running Jupyter notebook, we can see a websocket connection:

We can the click on that connection and monitor the messages being passed over it…

I thought this might help me debug / improve my Binder magic, but it hasn’t. The notebook looks like it sends an empty ping as a heartbeat (as per the docs), but if I try to send an empyt message from the magic it closes the connection? Instead, I send a message to the hearbeat channel…

PS sort of related, binderbot, “A simple CLI to interact with binder, eg run local notebooks on a remote binder”.