How do I print thread backtraces upon a puma kill?

Question

I have an app that has some operations that timeout every once in a while (given our Puma configured timeout) but given then process just dies and a new one comes over I have no way of knowing why/where the process was hung.

Is there a way for me to print all threads before Puma kills my process?

I've tried using on_worker_shutdown but that doesn't seem to be called on a timeout kill. This is a Rails 4.2 app running on Ruby 2.2.7.

Answer 1

You can try add a middleware that implements a time-out lower than the Puma and on this one you dumpy whatever you need/want.

It is not answering your question about Puma but might be a workaround to solve the issue that you have now.