Are extensions expected to work?

[dhirschfeld]

I'm trying to display a perspective widget in an ipywidgets.Output. It works in JupyterLab but seems to get stuck in retrolab.

...and I get a bunch of js errors:

[jtpio]

Thanks @dhirschfeld for the report.

Widgets and existing JupyterLab extensions are supported. So if perspective behaves like a normal widget then it should work.

The console errors seem to be coming from other extensions that expect to find tokens only exposed in JupyterLab. Usually it's a better practice to not require these tokens in extensions, but instead make them optional so they don't fail to activate in alternative lab distribution like RetroLab (retro doesn't have a status bar or layout restorer).

[dhirschfeld]

So if perspective behaves like a normal widget then it should work.

I wouldn't be surprised if it didn't. On the token issue, that sounds like a problem with the extensions so I'll close this as asked and answered - thanks!

[jtpio]

with the extensions so I'll close this as aksed and answered

Yes exactly.

Maybe we could actually improve the lab documentation to tell extension authors to try to make their plugins use optional dependencies as much as possible.

[dhirschfeld]

That would probably be well worthwhile. Maybe the cookiecutter needs updating too in case it's not doing the right thing?
https://github.com/jupyterlab/extension-cookiecutter-ts/

[jtpio]

The cookiecutter already sets the ISettingRegistry as optional, and doesn't have other dependencies at the moment so it should be good.

[timkpaine]

[timkpaine]

1. @dhirschfeld there are no perspective errors in the provided screenshot, if you have some in the console I can take a look
2. as with other partial jupyterlab frontend implementations, there are probably some dependencies which constitute a "normal" jupyterlab install that are missing. @jtpio The statements "Widgets and existing JupyterLab extensions are supported." and "The console errors seem to be coming from other extensions that expect to find tokens only exposed in JupyterLab" directly contradict one another. Also contradicts the description itself: "Extensions built for Jupyterlab should work as long as the components they depend on are part of this classic interface (for install RetroLab doesn't have the left, right and bottom areas)."

[timkpaine]

prior analysis which is suspect is relevant:
voila-dashboards/voila#481 (comment)

[dhirschfeld]

From past experience with voilà, any "normal" jupyterlab extension that interacts with @Lumino in a deeper way, or @jupyterlab in particular for rendermime extensions will have trouble

Yeah, my comment about not being surprised if it didn't work was just in regards to the fact that's it's not a "simple" widget and is therefore more likely to push the boundaries of what is required.

I actually tried to get perspective to work in voila first without any luck (so far). Since your PR is merged do you expect perspective should work with voila?

[timkpaine]

finos/perspective#1454

[dhirschfeld]

Thanks @timkpaine - I'm now subscribed to the issue & pr!

I'm just starting to try out perspective and it seems great. I do think a killer feature would be voila support as it makes distributing the results of your notebooks easier than having to tell people to just click the execute & run all button.

That's kind-of why I'm looking into retrolab too - if a user (non- developer/analyst) does have to run a notebook, retrolab might be a less intimidating entrypoint than the full-blown JupyterLab UI.

[timkpaine]

it used to support voila, im sure it will again given our extensive use of the perspective+voila combination for business users at JPMC (for exactly the scenarios you describe, no- or low-code users like sales people who want to see the results of analysts/quants/business intelligence/trader-developers). I would think the barrier to supporting arbitrary extensions is even lower for retrolab since it includes far more of the jupyterlab assets than voila, so we'll just need to track down which parts are missing and add them

[timkpaine]

An alternative answer which maybe @jtpio can clarify is from the README:
"Existing federated JupyterLab extensions listed via..."

So "No, only some federated extensions are supported".