Debug entire process group after both the main process and subprocesses have already started

[b39b332d]

I know I can debug all subprocesses by modifying the main process startup code to import debugpy. However, is there a way to attach to and debug an entire process group after both the main process and subprocesses have already started?
Currently, my approach is to attach to each process individually:

debugpy --listen localhost:port1 --pid <pid_of_proc1>
debugpy --listen localhost:port2 --pid <pid_of_proc2>

However, this creates separate, isolated debug sessions for each process. Is there any way to achieve the same unified debugging experience as when debugpy is imported at the main process startup (with subProcess=True)? Ideally, I'd like to:

Attach to an already-running process group
Have all subprocesses automatically included in a single coordinated debugging session
Avoid having to manually attach to each subprocess with separate ports

Is this possible with debugpy's current architecture, or would this require creating a custom wrapper/tool?

[rchiodo]

Debugging subprocesses in Debugpy is handled by monkey patching the code that starts subprocesses. You can see it here:

debugpy/src/debugpy/_vendored/pydevd/_pydev_bundle/pydev_monkey.py

Line 988 in 6cbdf87

def patch_new_process_functions():

I was thinking there might need to be more patching for groups, but looking at it now, I'm not sure why it wouldn't just work. Attach AFAIK does the monkey patching too as long as you have 'subProcess': true in your launch.json.

So I'm not sure why it doesn't already work.

[b39b332d]

Thanks for your reply!
Sorry if I wasn't clear earlier. If I attach to the main process before any fork() or exec() calls, it works perfectly—all child processes created afterward are automatically included in the debug session.
However, I'm wondering about the scenario where I need to attach after the child processes have already been created. In this case, it seems I have to manually attach to each subprocess individually.

[rchiodo]

Yeah, there's no code at the moment to automatically attach to the other processes. That would likely be possible but it isn't currently supported. You have to attach to the child processes manually.