mpdb

mpdb (Multiprocess PDB) is a lightweight distributed debugger built on top of ipdb.

Repository: https://github.com/zzqq2199/mpdb

Note: This project was formerly known as dpdb. The dpdb package name on PyPI was already taken, so it has been renamed to mpdb. Both import mpdb and import dpdb are supported with identical functionality.

Release Notes

• 1.2.1: improve default web header description and link rendering.
  • mpdb now sets a default web header description on first import only, avoiding overrides when users have already called set_description(...).
  • Default subtitle is updated to an official site link: https://github.com/zzqq2199/mpdb.
  • Web UI header rendering now supports safe <a> links in both title and subtitle.
  • dpdb now sets its default title via set_description(title="DPDB Web Debugger").
  • Minor backend robustness updates: add typing for description state, guard pkgutil.get_data(...) when __package__ is empty, and only invoke saved signal handlers when callable.
• 1.2.0: add set_description() API for customizing web UI header.
  • New mpdb.web_pdb.set_description(title, subtitle) function to override the default "MPDB Web Debugger" title and "by zhouquan" subtitle at runtime.
  • The /status API now includes title and subtitle fields when set.
  • The web UI dynamically updates the header text from the backend status response.
  • dpdb package calls set_description("DPDB Web Debugger") automatically on import.
• 1.1.2: update the README documentation.
  • Add the repository link for easier source code access.
  • Clarify installation options: PyPI as recommended, GitHub as optional.
• 1.1.1: rename internal identifiers and assets to mpdb.
  • All internal identifiers (dpdb_rank → rank, dpdb_world_size → world_size) renamed for consistency.
  • Demo files and test files renamed to mpdb.
  • localStorage keys in web UI updated to mpdb_* prefix.
  • Prompt updated to [mpdb]>>>.
• 1.1.0: rename from dpdb to mpdb.
  • PyPI package name dpdb was already taken, renamed to mpdb (Multiprocess PDB).
  • Full backward compatibility: both import mpdb and import dpdb work identically.
  • pip install mpdb is the recommended installation method.
• 1.0.0: first public release version.
  • single-process debugging
  • distributed command broadcast
  • file-based synchronization for non-torch.distributed scenarios
  • a built-in web UI
  • switching between web and terminal modes during a session

Install

Recommended (PyPI):

pip install mpdb

Optional (GitHub):

pip install git+https://github.com/zzqq2199/mpdb.git

Quick Start

import mpdb

def train():
    for step in range(10):
        if step == 5:
            mpdb.set_trace()

Run a script directly:

python -m mpdb your_script.py

Demo

The standalone repository ships with runnable examples under demo/:

python demo/demo_mpdb.py --mode single
python demo/demo_mpdb.py --mode file
python demo/demo_mpdb.py --mode torch

There is also a helper launcher for the torch demo:

bash demo/launch_mpdb.sh

Notes

• torch is optional and only required when you use sync_method='torch'.
• The web UI template is packaged with the wheel and works with pip install mpdb.
• Both import mpdb and import dpdb are supported and behave identically.