Make the maximum number of output lines configurable

[ericsalim]

Currently, the maximum number of output lines are limited to 1000 lines. See #803. I believe the choice of number is arbitrary.

I use Livebook to make test calls to API endpoints. Sometimes the number of lines in the response body exceeds 1000. There is no way for me to get the full response body.

Since there is no one-size-fits-all number, I suggest making this configurable as an environment variable. The default value should stay 1000. But the user can configure the number based on the machine capability.

[jonatanklosko]

Hey @ericsalim, I think in that case the best option is to use Kino.inspect, or ... |> Kino.Text.new(terminal: true) |> Kino.render(). This way you get a separate output block and it's never truncated. The good thing about this approach is that it works for anyone else using the notebook, without additional configuration.

[jonatanklosko]

Ah, and there's also Kino.Tree, which may be useful for exploring nested data, like API responses!

[josevalim]

Something we could do is to show a tiny message saying the output has been truncated and add a cell option to not truncate outputs. Clicking the message could disable truncation and reevaluate.

[ericsalim]

Using Kino.Text works for me. So, my issue is resolved. Thank you!

Adding an option to not truncate output will certainly help for basic users who do not use Kino. But one thing worth considering is this: If the output is huge, it means the process is heavy. If the process if heavy, the user might not want to run it once before the option appears.