pyrasite

While it's certainly much harder in managed runtimes, I've been quite happy with gdb's "where" output on JNI-bound or syscall-stuck JVM cores, and jstack (and more modern friends) where that didn't work. For my other HLL of choice, pyrasite[1] works quite well. When using all of those tools, I encountered significant out-of-the-box usability issues until I learned what those debugger-esque tools were doing with regards to their "target" programs' (or their postmortem heaps) stacks, signal handlers, and allocators. Combining the understanding of the latter concepts with the former tools is a killer combo, and, while I can't speak directly to your counterexample of the NodeJS runtime, I would be extremely surprised if tooling did not exist to perform similar debugging tasks with it. 1. https://github.com/lmacken/pyrasite

Sibling comment suggests Pyrasite for this: https://github.com/lmacken/pyrasite

See this file: https://github.com/lmacken/pyrasite/blob/develop/pyrasite/in... It uses GDB to attach to the process. And then evaluates the code inside the process using GDB.

As a curiosity/hack you can almost get there with pyrasite (https://github.com/lmacken/pyrasite) and def newfn(): ... oldfn.__code__ = newfn.__code__ del newfn There's a difficulty with __globals__ and __closures__ but I found the patch at the end of this post https://hardenedapple.github.io/stories/computers/python_fun... appears to allow full redefinition. Disclaimer: I'm pretty confident there will be edge cases and/or bugs with these approaches.

For Python, you can just use Pyrasite (https://github.com/lmacken/pyrasite) and inject a script which prints a stack trace for all threads. I've done this to debug OpenStack in the past and it worked very well. There are many similar projects for Python, I used this one since it's in the RHEL repo. Useful summary on StackOverflow: https://stackoverflow.com/questions/4163964/python-is-it-pos...

Just read this file: https://github.com/lmacken/pyrasite/blob/develop/pyrasite/in... it's rather straightforward.

GDB uses a system call(s) to attach to the running process[1], and python exposes an API that lets you evaluate code in the current VM context[2]. Specifically, https://github.com/lmacken/pyrasite/blob/develop/pyrasite/in... [1] http://aosabook.org/en/gdb.html [2] https://docs.python.org/2/c-api/veryhigh.html

This is probably the most featured / well known one: https://github.com/lmacken/pyrasite