I have found Elixir as a whole to be amazing, but the debugging process to be painful. Maybe its because I'm used to using Chrome's developer tools (since I mostly debug JavaScript), but I really wish that debugging on Elixir could be simpler. Using printf's is just too painful and feels backwards.
I would recommend you learn the dbg module that comes with Erlang. Its a great tracing debugger able to trace existing code in runtime without having to modify the source. There are also several wrappers on top of the Erlang tracing tools, like Recon for example.
