Coloring exceptions from Python on a terminal

Question

Is there an easy way to get the message of the exception to be colored on the command line? For example

def g():    f()
def f():    1/0
g()

Answer 1

You can assign a custom function to the sys.excepthook handler. The function is called whenever there is a unhandled exception (so one that exits the interpreter).

def set_highlighted_excepthook():
    import sys, traceback
    from pygments import highlight
    from pygments.lexers import get_lexer_by_name
    from pygments.formatters import TerminalFormatter

    lexer = get_lexer_by_name("pytb" if sys.version_info.major < 3 else "py3tb")
    formatter = TerminalFormatter()

    def myexcepthook(type, value, tb):
        tbtext = ''.join(traceback.format_exception(type, value, tb))
        sys.stderr.write(highlight(tbtext, lexer, formatter))

    sys.excepthook = myexcepthook

set_highlighted_excepthook()

This version uses the pygments library to convert the traceback text into one formatted with ANSI coloring, before writing it to stderr.

Someone turned this into a project that detects terminal support and lets you set the pygments style, see colored-traceback.py.