When running as a server extension, no ability to display python errors with --debug

[aschlaep]

We have Voila running as a server extension. When there is a python error, Voila displays "There was an error when executing cell [X]. Please run Voilà with --debug to see the error message." We can customize this message with cell_error_instruction, but we can not show the python stack. It seems that there is no way to run with the --debug flag when running as a sever extension, rather than running it directly.

[aschlaep]

Entered per @maartenbreddels request.

[jeffyjefflabs]

You can set c.Voila.show_tracebacks = True in jupyter_notebook_config.py, unless you're trying to avoid restarting?