Methods to troubleshoot Voila getting stuck on `Executing x of y`

[afonit]

Is there a parameter to cause voila to be very verbose in what it is doing? I have read through the documentation and I am not seeing it.

I run voila on an ubuntu server and almost always runs amazingly well.

A day or so ago I upgraded to the latest packages for lab and voila, my notebooks started to get stuck on Executing x of y when loaded with voila. (Some will load every time, some will not load, some can be refreshed over and over and sometimes they load)

Which notebook and which x of y they were getting stuck on seems quite random, but some will not run and always get stuck.

I am wondering if there is or could be documentation detailing the appropriate methods for troubleshooting?

Things I have tried:

1. Checking journalctl

   sudo journalctl -u voila -f
   sudo journalctl -f

2. Creating a new mamba environment and installing everything fresh and with the most current packages. When doing this I did ensure to change the /etc/systemd/system/voila.service so it was pointing to the new environment

   sudo systemctl daemon-reload

   I would then

   sudo systemctl restart voila

   and check to make sure

   sudo systemctl status voila

   showed that the proper new environment was loaded and running. sudo journalctl -u voila -f

The journal would not provide any detail beyond:

Sep 14 20:55:29 prod-066998 voila[24032]: [Voila] Starting buffering for b3cd50e0-080c-4f9e-a658-fcb9aeb190e4:6a99f980-fbc7-4b2f-bf2d-0496754265a0
Sep 14 20:55:29 prod-066998 voila[24032]: [Voila] Kernel shutdown: b3cd50e0-080c-4f9e-a658-fcb9aeb190e4

3. Looking in the Developer Tools console in chrome This just prints

   Ok, voila is still executing... in the console output the same line as above about every 10 seconds.

4. I use cell tags of hide, so I will hide/delete cells to try and get to the cells which may be causing an issue (but again this can be random and will be at a different x of y for the same notebook, each time it is refreshed in Voila).

Is there a way or a mechanism to discover (or see more detailed logging) what voila is getting hung up on in the Executing x of y?

[afonit]

Not sure if the below is related - because I tried running example notebooks from each of the projects and they load fine in voila - and my own notebooks run with the libraries although with the afore mentioned inconsistencies and sticking on x of y for some of them.

---

I created another new environment, this time I thought to go to the root page of voila (the tree) instead of the notebooks and look at the webconsole, I now see these errors:

This is with: python 3.11 jupyterlab 4.0.6 jupyterlab_server 2.25.0 jupyter_server 2.7.3 jupyterlab_widgets 3.0.9 ipydatagrid 1.2.0 bqplot 0.12.40 ipyleaflet 0.17.4 voila 0.5.3

[afonit]

for my own personal issue, I went back into the original environment and downgraded the packages to what they were before to see if I would get the consistency of voila loading notebooks back:

mamba install -c conda-forge jupyter-server-mathjax=0.2.3 jupyter_client=6.1.12 jupyter_core=4.11.0 jupyter_server=1.23.4 jupyterlab=3.6.3 jupyterlab_widgets=3.0.3 nbclassic=0.3.1 tornado=6.1 voila=0.4.0

That worked. Not sure why all the new packages were leading to inconsistent loads and getting stuck on x of y. I would still love some advice on mechanisms to troubleshoot that when voila gets stuck on x of y etc...

[martinRenou]

https://github.com/voila-dashboards/voila/pull/1394 may help troubleshoot this and make things more stable regarding custom widgets.

[afonit]

Thank you, I will watch that issue and try it out when released.

[afonit]

Linking to this issue as the root cause seems to have been identified https://github.com/voila-dashboards/voila/issues/1428