Programming Erlang, 2nd Edition

Tracing Messages and Process Execution

You can always trace a process without having to compile your code in a special way. Tracing a process (or processes) provides a powerful way of understanding how your system behaves and can be used to test complex systems without modifying the code. This is particularly useful in embedded systems or where you cannot modify the code being tested.

At a low level, we can set up a trace by calling a number of Erlang BIFs. Using these BIFs for setting up complex traces is difficult, so several libraries are designed to make this task easier.

We’ll start by looking at the low-level Erlang BIFs for tracing and see how to set up a simple tracer; then we’ll review the libraries that can provide a higher-level ...