vscode-jupyter: Unable to use widgets (itkwidgets) non-local (WSL 2, docker, remote-ssh) scenario (was: Configuration setting of widgetScriptSources does not work/unclear)

Environment data

• VS Code version: 1.52.0
• Jupyter Extension version (available under the Extensions sidebar): 2020.12.xxx
• Python Extension version (available under the Extensions sidebar): 2020.12.xxx
• OS (Windows | Mac | Linux distro) and version: Windows Subsystem for Linux 2 with Ubuntu 20.04 LTS
• Python and/or Anaconda version: 3.8.5
• Type of virtual environment used (N/A | venv | virtualenv | conda | …): venv
• Jupyter server running: Local

Expected behaviour

I imported ‘itkwidgets’ to show an image

Actual behaviour

I get an error message:

Widgets require us to download supporting files from a 3rd party website. Click here to enable this or click here for more information. (Error loading itkwidgets:^0.32.0). Widgets require us to download supporting files from a 3rd party website. Click here to enable this or click here for more information. (Error loading itkwidgets:^0.32.0). Widgets require us to download supporting files from a 3rd party website. Click here to enable this or click here for more information. (Error loading itkwidgets:^0.32.0).

(Really, if you try 3 times, the error gets concatenated 3 times)

XXX

Steps to reproduce:

I submitted the same issue here, since I’m not sure whether it is an itkwidgets issue or a VSCode/Jupyter issue.

https://github.com/InsightSoftwareConsortium/itkwidgets/issues/396

I created this notebook that doesn’t run in my configuration

import itk
from itkwidgets import view
from urllib.request import urlretrieve
import os

# Download data
file_name = '005_32months_T2_RegT1_Reg2Atlas_ManualBrainMask_Stripped.nrrd'
if not os.path.exists(file_name):
    url = 'https://data.kitware.com/api/v1/file/564a5b078d777f7522dbfaa6/download'
    urlretrieve(url, file_name)
image = itk.imread(file_name)
view(image, rotate=True, axes=True, vmin=4000, vmax=17000, gradient_opacity=0.9)

[NOTE: Self-contained, minimal reproducing code samples are extremely helpful and will expedite addressing your issue]

1. XXX

Logs

> ~/.venv/bin/python ~/.vscode-server/extensions/ms-toolsai.jupyter-2020.12.414227025/pythonFiles/pyvsc-run-isolated.py -c "import ipykernel"
> ~/.venv/bin/python ~/.vscode-server/extensions/ms-toolsai.jupyter-2020.12.414227025/pythonFiles/pyvsc-run-isolated.py vscode_datascience_helpers.daemon --daemon-module=vscode_datascience_helpers.kernel_launcher_daemon -v
Error 2020-12-17 08:52:47: Script source for Widget itkwidgets@^0.32.0 not found

Output for Jupyter in the Output panel (View→Output, change the drop-down the upper-right of the Output panel to Jupyter)

XXX