Add kernel path for thebelab

[joergbrech]

This should hopefully fix #107, now that executablebooks/thebe#114 is fixed.

It doesn't really make sense to merge this until a new Thebelab version (>0.4.0) is released and this can be tested, so I added a [WIP] label to the PR name for now.

[choldgraf]

woot! this looks nice - let's give it a whirl once the new thebelab is up!

[choldgraf]

Just a note on this - it looks like 0.4 is now on unpkg so can we test this?

[joergbrech]

I think 0.4.0 has been out for a while now and it doesn't include the changes yet...we need to wait for the next version >0.4.0

[choldgraf]

ok, 0.5.1 is now out, so this should have fixed things! I fixed conflicts and updated the code a bit to be cleaner...but it should work now, can somebody confirm?

[joergbrech]

I will check next week!

[joergbrech]

Ok, so I tested this on my site (how would you unit-test this?), and the generated html looks good:

<script type="text/x-thebe-config">
    {
      requestKernel: true,
      binderOptions: {
        repo: 'joergbrech/Modellbildung-und-Simulation',
        ref: '2-thebelab-directory',
      },
      codeMirrorConfig: {
        theme: "abcdef"
      },
      kernelOptions: {
        name: 'octave',
        path: "content/00_einleitung"
      }
    }
</script>

Running thebelab uses the specified path, so this seems to work well, but there is still a problem:

kernelOptions.name is not respected. A python kernel is started and not an octave kernel. Opening the Jupyter Notebook on binder works fine.

[choldgraf]

interesting - so kernelOptions.path is respected, but kernelOptions.name is not?

for unit testing, that's a great question :-) I have struggled with "how to unit test javascript + html" since the beginning of jupyter book. I think there are frameworks for doing this but none that I've had the time to learn and implement

[joergbrech]

Seems like it. When pressing the thebelab button, the console prints

Binder: server running at https://hub.gke.mybinder.org/user/joergbrech-mode--und-simulation-i1emjsxk/
thebelab.js:416:16
Starting WebSocket: wss://hub.gke.mybinder.org/user/joergbrech-mode--und-simulation-i1emjsxk/api/kernels/4bbd8147-e749-46ff-9775-231c4ebb1b32 default.js:51:27
Kernel: connected (4bbd8147-e749-46ff-9775-231c4ebb1b32)

and when opening the url at https://hub.gke.mybinder.org/user/joergbrech-mode--und-simulation-i1emjsxk/api/kernels to check for the running kernel I get the response

[{"id": "4bbd8147-e749-46ff-9775-231c4ebb1b32", "name": "python3", "last_activity": "2019-11-05T06:12:15.829162Z", "execution_state": "idle", "connections": 1}]

So apparently a python3 kernel is started.

And since thebelab is running with a python kernel instead of an octave kernel, I can copy

import os
print(os.getcwd())

into any of the code cells to verify that binder is running in the correct path.

I will try and dig deeper, but this new(ish) kernel issue might be unrelated to #107 and this PR...

[joergbrech]

Found it! It turns out we should use kernelName and not name, since thebelab now uses the session API and not the kernel API:

• https://github.com/minrk/thebelab/pull/131/files
• https://github.com/SylvainCorlay/jupyter-js-services/blob/master/README.md

I am not sure why this test fails?

[choldgraf]

This LGTM, thanks very much for the fix @joergbrech !!