The code is available here. It’s made exclusively for that demo, so it’s not the prettiest nor particularly safe You’ll probably be better off using recon or redbug in real prod.

[Turning on the @sasajuric Batman spotlight]

Just reading it, I have no idea why I’m calling trace twice, returning an error if the second one fails. A single trace call followed by a call to trace_pattern should work.

We need an “Elixir in Anger”

would you please point into the direction of how you would do that with recon or redbug in prod?

Both of these tools have some form of such safe guards (though IIRC not exactly the same). A good place to learn more would be docs:

https://ferd.github.io/recon/recon_trace.html
https://hexdocs.pm/redbug/