Force reload on external file update?

Elixir Framework Forums Livebook Forum
,
1

Is there a way to force LiveBook to reload a cell when an external file has been updated that needs to be read in, and render later impacted cells as stale?

weights_file = "weights.csv"
weights_df = Excel.excel_to_df!(weights_file)

I’ve tried the following suggestion from Claude AI, but that doesn’t work:

# Add this to force reload when files change
_ = File.stat!(weights_file)
2

Maybe the @external_resource module attribute can help?

3

There is no way to automatically reevaluate the cell when that happens. You would need to use a library for watching for the file changes, but then the handling would be asynchronous, not part of the sequential notebook flow.

1 Like
4

You should be able to use a file watcher and setup a Kino.Proxy to execute the refresh following this example: Kino.Proxy — Kino v0.14.2. I believe the proxy needs an application so you lose interactivity but applications execute top down and stay active. First run could load your initial dataset into weights.csv and use Kino.start_child to start a file watcher process. You may also be able to just execute it inline but I suspect the supervisor gives you better control. The watcher would listen for changes and make a Req call to your proxy endpoint that refreshes the dataset again.

I’ve yet to validate if this works as I expect it but all of the pieces are there.

1 Like