Debugging Tools

python programming snippet

• Debugging tools list - Python 3.7: https://docs.python.org/3/library/debug.html
  • vprof - Profiler with nice in-browser visualisation
    • multi-word argument bug
  • py-spy
    • Implemented in rust - distributed over pypi (!)
    • Has record, top, dump
    • Can profile already running python scripts
    • useful for the case where you just need a single call stack to figure out where your python program is hung on.
    • py-spy works by directly reading the memory of the python program using the process_vm_readv system call on Linux, the vm_read call on OSX or the ReadProcessMemory call on Windows.
    • Can be configured to not block the python program! --noblocking
• Print-f style debugging: https://github.com/cool-RR/PySnooper, https://github.com/bergercookie/vim-debugstring
• Remote debugging with rpdb: https://coderwall.com/p/ttbtgq/python-remote-debugging-with-pdb
• Use ipython! - https://switowski.com/blog/ipython-debugging
  • %run -d <path/to/script> --> # Launch a script from ipython
  • %pdb -> Stop on any error launch the debugger there (when running a script)
  • from IPython import embed; embed()
  • %debug -> Load a stack trace of the latest exception
• Instead of ipdb, use pdbpp:
  • Use sticky mode: sticky
  • The module is called pdb.py so, you can invoke it with the same import pdb; pdb.set_trace()