Python debugging tips [closed]

Answer 1

Getting a stack trace from a running Python application

There are several tricks here. These include

• Breaking into an interpreter/printing a stack trace by sending a signal
• Getting a stack trace out of an unprepared Python process
• Running the interpreter with flags to make it useful for debugging

Answer 2

If you don't like spending time in debuggers (and don't appreciate poor usability of pdb command line interface), you can dump execution trace and analyze it later. For example:

python -m trace -t setup.py install > execution.log

This will dump all source line of setup.py install execution to execution.log.

To make it easier to customize trace output and write your own tracers, I put together some pieces of code into xtrace module (public domain).

Answer 3

the obvious way to debug a script

python -m pdb script.py

• useful when that script raises an exception
• useful when using virtualenv and pdb command is not running with the venvs python version.

if you don't know exactly where that script is

python -m pdb ``which <python-script-name>``

Answer 4

ipdb is like pdb, with the awesomeness of ipython.

Answer 5

If you are familiar with Visual Studio, Python Tools for Visual Studio is what you look for.

Answer 6

PyDev

PyDev has a pretty good interactive debugger. It has watch expressions, hover-to-evaluate, thread and stack listings and (almost) all the usual amenities you expect from a modern visual debugger. You can even attach to a running process and do remote debugging.

Like other visual debuggers, though, I find it useful mostly for simple problems, or for very complicated problems after I've tried everything else. I still do most of the heavy lifting with logging.