Colored Traceback

Automatically color Python's uncaught exception tracebacks.

This one's for anybody who's ever struggled to read python's stacktraces on the terminal. Something about the two-lines-per-frame approach really just makes them tough to scan visually.

Compare this:

Traceback (most recent call last):
  File "./workflowy.py", line 525, in <module>
    main()
  File "./workflowy.py", line 37, in main
    projects = cli.load_json(args, input_is_pipe)
  File "./workflowy.py", line 153, in load_json
    return json.load(sys.stdin)
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/json/__init__.py", line 290, in load
    **kw)
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/json/__init__.py", line 338, in loads
    return _default_decoder.decode(s)
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/json/decoder.py", line 365, in decode
    obj, end = self.raw_decode(s, idx=_w(s, 0).end())
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/json/decoder.py", line 383, in raw_decode
    raise ValueError("No JSON object could be decoded")
ValueError: No JSON object could be decoded

To this:

Traceback (most recent call last):
  File "./workflowy.py", line 525, in <module>
    main()
  File "./workflowy.py", line 37, in main
    projects = cli.load_json(args, input_is_pipe)
  File "./workflowy.py", line 153, in load_json
    return json.load(sys.stdin)
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/json/__init__.py", line 290, in load
    **kw)
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/json/__init__.py", line 338, in loads
    return _default_decoder.decode(s)
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/json/decoder.py", line 365, in decode
    obj, end = self.raw_decode(s, idx=_w(s, 0).end())
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/json/decoder.py", line 383, in raw_decode
    raise ValueError("No JSON object could be decoded")
ValueError: No JSON object could be decoded

Installation

Through pip:

pip install colored-traceback

Or directly:

git clone http://www.github.com/staticshock/colored-traceback.py
python setup.py install

On Windows, which has no real support for ANSI escape sequences, there's an additional dependency on `colorama`:

pip install colorama

Usage

Colored Traceback can be executed as a module:

python -m colored_traceback somefile.py

Colored Traceback also works well within a script or even directly in the interpreter REPL. Standard usage will color the output, unless it's being redirected to a pipe:

import colored_traceback
colored_traceback.add_hook()

If want to retain color even when stderr is being piped, tack on an always=True argument:

import colored_traceback
colored_traceback.add_hook(always=True)

There are also a couple of convenience imports, which get the footprint down to one line:

# Same as add_hook()
import colored_traceback.auto

# Same as add_hook(always=True)
import colored_traceback.always

It goes without saying that you might want to catch ImportError, making the presence of the package optional:

try:
    import colored_traceback.auto
except ImportError:
    pass