Multiprocess debugging support?

[Zloool]

Environment data

VS Code version: 1.18.1
Python Extension version: 0.8.0
Python Version: 3.6.3
OS and version: Microsoft Windows [Version 10.0.16299.64]

Actual behavior

Debugger is working only in main process.

Expected behavior

Debugger would stop on breakpoints in child processes.

Steps to reproduce:

• Use this code:
  A.py

from multiprocessing import Process, Event

import B

if __name__ == '__main__':
    update_event = Event()
    client_proc = Process(
                args=(update_event,),
                name="client",
                target=B.TestFunc,
            )
    client_proc.start()

    import time
    time.sleep(100)

B.py

import time

def TestFunc(a):
    while True:
        time.sleep(5)
        print(a)

• Put breakpoint on last line of B.py
• Run debug

Logs

Output from Python output panel

Nothing special there

Output from Console window (Help->Developer Tools menu)

t.log @ /C:/Program Files/Microsoft VS Code/resources/app/out/vs/workbench/workbench.main.js:9
/C:/Program Files/Microsoft VS Code/resources/app/out/vs/workbench/workbench.main.js:10 spawn ctags ENOENT: Error: spawn ctags ENOENT
	at exports._errnoException (util.js:1050:11)
	at Process.ChildProcess._handle.onexit (internal/child_process.js:193:32)
	at onErrorNT (internal/child_process.js:367:16)
	at _combinedTickCallback (internal/process/next_tick.js:80:11)
	at process._tickCallback (internal/process/next_tick.js:104:9)
e.onUnexpectedError @ /C:/Program Files/Microsoft VS Code/resources/app/out/vs/workbench/workbench.main.js:10
/C:/Program Files/Microsoft VS Code/resources/app/out/vs/workbench/workbench.main.js:9 [Extension Host] (node:9236) DeprecationWarning: os.tmpDir() is deprecated. Use os.tmpdir() instead.
t.log @ /C:/Program Files/Microsoft VS Code/resources/app/out/vs/workbench/workbench.main.js:9


raw.marked.js:15 [Violation] Added non-passive event listener to a scroll-blocking 'mousewheel' event. Consider marking event handler as 'passive' to make the page more responsive.
raw.marked.js:15 [Violation] Added non-passive event listener to a scroll-blocking 'touchstart' event. 
// More same output
raw.marked.js:15 [Violation] Added non-passive event listener to a scroll-blocking 'touchstart' event. Consider marking event handler as 'passive' to make the page more responsive.
raw.marked.js:15 [Violation] Added non-passive event listener to a scroll-blocking 'touchmove' event. Consider marking event handler as 'passive' to make the page more responsive.

[brettcannon]

I'm pretty sure that multi-process support isn't in ptvsd, but @DonJayamanne might know better than I do.

[DonJayamanne]

Unfortunately no, multi process debugging is currently not supported.

[Zloool]

Thanks for the answer @DonJayamanne , will switch to multithreading for debug purposes.

[DonJayamanne]

Upstream issue microsoft/ptvsd#57

[gandalfsaxe]

Will this issue also cover Python multiprocessing's Pool().map?

https://docs.python.org/3.4/library/multiprocessing.html

[brettcannon]

@gandalfsaxe you will have to ask on the upstream issue.

[DonJayamanne]

Closing in favor of #80