Add callback to `Kino.interrupt!` about kino HOT 5 CLOSED

@NduatiK you can do this:

if HTTPPort.in_use?(default_port) do
  kill? = Kino.Shorts.read_checkbox("Kill port 4000")

  if kill? do
    HTTPPort.kill_process(default_port)
  else
    Kino.interrupt!(:normal, "Port 4000 is taken")
  end
end

Since you start the LVN server in the notebook, it would make sense to pick a more random port, so it's much less likely that people run into conflict :)

from kino.

At first I am 👎 because if you need to perform such tasks, it means you are generally unable to reevaluate the cell in the first place? Can you provide a more concrete example? Who is using that Port? Where and how was it started?

from kino.

Sure thing.

I mean that there is a system process somewhere that is making use of the HTTP port (not Elixir port 🙃).

Let's say that a new Elixir developer has run mix phx.server from their terminal.
If they attempts to start one of LiveView Native's tutorials, we would like to tell them that the default port used by LiveView Native (4000) is in use and offer to kill the system process holding the port.

The idea is that to block the execution until that system process is killed, and to offer the user a way to kill it.
Kino.interrupt! currently lets us block execution if some condition is not met. It would be nice to be able to execute some code before attempting to reevaluate the code.

from kino.

Another use case would be in allowing developers to specify potentially destructive actions that needs confirmation.

For example, imagine we are using a Livebook app to send out daily emails.
In general we might always allow emails to go out. But if we detect that a user is sending the second email of the day, we might want to them to confirm that they really do want to send it.

from kino.

@jonatanklosko, we came up with a similar workaround, but yours is much cleaner.

Thanks!

from kino.