Hide the Traceback stack trace in the browser for errors during app initialization

[dataF0g]

Hi everyone,

I've noticed that if an error occurs during the initialization of a component, the full Traceback is displayed directly in the browser.

While this is helpful for debugging, I'd like to avoid showing the internal stack trace and sensitive path information to end-users in a production-like environment.

Here is a minimal reproducible example:

import panel as pn
import param

class ErrorExample(pn.viewable.Viewer):
    param_a = param.String(default="Example")

    def __init__(self, **params):
        super().__init__(**params)
        raise RuntimeError("An error occurred during initialization")

    def __panel__(self):
        return pn.Column(f"# {self.param_a}")

def get_app():
    return ErrorExample()

if __name__ == "__main__":
    pn.serve(get_app)

Currently, when I run this and open the browser, I see:

RuntimeError

Traceback (most recent call last):
  File ".../panel/io/handlers.py", line 366, in run_app
    handler._func(doc)
  File ".../panel/io/application.py", line 75, in _eval_panel
    panel = panel()
            ^^^^^^^
  File "error_example.py", line 18, in get_app
    return ErrorExample()
           ^^^^^^^^^^^^^^
  File "error_example.py", line 11, in __init__
    raise RuntimeError("An error occurred during initialization")
RuntimeError: An error occurred during initialization

Question:

Is there a built-in Panel or Bokeh configuration (or a recommended pattern) to suppress this traceback in the UI and perhaps show a custom "Internal Server Error" message instead, while still logging the full error to the server console?

Thanks in advance for any help!

Versions:

bokeh==3.8.2
panel==1.8.10

Discourse discussion: https://discourse.holoviz.org/t/how-to-hide-the-traceback-stack-trace-in-the-browser-for-errors-during-app-initialization/9262/1

[holovizbot]

This issue has been mentioned on HoloViz Discourse. There might be relevant details there:

https://discourse.holoviz.org/t/how-to-hide-the-traceback-stack-trace-in-the-browser-for-errors-during-app-initialization/9262/4