Troubleshooting Voila Deployment on Heroku: App Boot Timeout (H20 Error) with Jupyter Notebook

Question

I am encountering an issue deploying a Jupyter Notebook using Voila on Heroku, specifically an H20 App boot timeout error. The application starts successfully as indicated by the logs, but then it fails to become accessible, resulting in a timeout. Here's my repo

Here are the key details:

• Environment: The app is a Jupyter Notebook being served through Voila on Heroku.

• Error Observed: The primary issue is a H20 App boot timeout error from Heroku. This occurs after the logs indicate that Voila has successfully started and is running.

• Log Details: The logs show that Voila is using the /tmp directory for connection files and serving static files from the appropriate location. However, Voila appears to be running at http://localhost:port_number/, which seems unusual for a Heroku deployment.

Procfile Configuration: My Procfile is set up as follows: web: voila --port=$PORT --no-browser --strip_sources=True All_tests_launcher/all_tests_launcher.ipynb

Attempts to resolve: I’ve tried ensuring Voila binds to 0.0.0.0 instead of localhost and checked for any long startup times or blocking operations in the notebook. The notebook runs fine locally.

I am seeking insights into why this error is occurring and how to resolve it to get the Voila app running smoothly on Heroku.