Python Tracebackplus

tracebackplus.py

"""More comprehensive traceback formatting for Python scripts.

To enable this module, do:

    import tracebackplus; tracebackplus.enable()

at the top of your script.  The optional arguments to enable() are:

    logdir      - if set, tracebacks are written to files in this directory
    context     - number of lines of source code to show for each stack frame

By default, tracebacks are displayed but not saved and the context is 5 lines.
Alternatively, if you have caught an exception and want tracebackplus to display it
for you, call tracebackplus.handler().  The optional argument to handler() is a
3-item tuple (etype, evalue, etb) just like the value of sys.exc_info().
"""

'''
Licensing:

MIT License

Copyright (c) 2020 Kelly Brazil

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
tracebackplus was derived from the cgitb standard library module. As cgitb is being
deprecated, this simplified version of cgitb was created.

https://github.com/python/cpython/blob/3.8/Lib/cgitb.py

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'''

import inspect
import keyword
import linecache
import os
import pydoc
import sys
import tempfile
import time
import tokenize
import traceback


__UNDEF__ = []                          # a special sentinel object


def lookup(name, frame, locals):
    """Find the value for a given name in the given environment."""
    if name in locals:
        return 'local', locals[name]
    if name in frame.f_globals:
        return 'global', frame.f_globals[name]
    if '__builtins__' in frame.f_globals:
        builtins = frame.f_globals['__builtins__']
        if isinstance(builtins, dict):
            if name in builtins:
                return 'builtin', builtins[name]
        else:
            if hasattr(builtins, name):
                return 'builtin', getattr(builtins, name)
    return None, __UNDEF__


def scanvars(reader, frame, locals):
    """Scan one logical line of Python and look up values of variables used."""
    vars, lasttoken, parent, prefix, value = [], None, None, '', __UNDEF__
    for ttype, token, start, end, line in tokenize.generate_tokens(reader):
        if ttype == tokenize.NEWLINE:
            break
        if ttype == tokenize.NAME and token not in keyword.kwlist:
            if lasttoken == '.':
                if parent is not __UNDEF__:
                    value = getattr(parent, token, __UNDEF__)
                    vars.append((prefix + token, prefix, value))
            else:
                where, value = lookup(token, frame, locals)
                vars.append((token, where, value))
        elif token == '.':
            prefix += lasttoken + '.'
            parent = value
        else:
            parent, prefix = None, ''
        lasttoken = token
    return vars


def text(einfo, context=5):
    """Return a plain text document describing a given traceback."""
    etype, evalue, etb = einfo
    if isinstance(etype, type):
        etype = etype.__name__
    pyver = 'Python ' + sys.version.split()[0] + ': ' + sys.executable
    date = time.ctime(time.time())
    head = '%s\n%s\n%s\n' % (str(etype), pyver, date) + '''
A problem occurred in a Python script.  Here is the sequence of
function calls leading up to the error, in the order they occurred.
'''

    frames = []
    records = inspect.getinnerframes(etb, context)
    for frame, file, lnum, func, lines, index in records:
        file = file and os.path.abspath(file) or '?'
        args, varargs, varkw, locals = inspect.getargvalues(frame)
        call = ''
        if func != '?':
            call = 'in ' + func + \
                inspect.formatargvalues(args, varargs, varkw, locals,
                                        formatvalue=lambda value: '=' + pydoc.text.repr(value))

        highlight = {}

        def reader(lnum=[lnum]):
            highlight[lnum[0]] = 1
            try:
                return linecache.getline(file, lnum[0])
            finally:
                lnum[0] += 1
        vars = scanvars(reader, frame, locals)

        rows = [' %s %s' % (file, call)]
        if index is not None:
            i = lnum - index
            for line in lines:
                num = '%5d ' % i
                rows.append(num + line.rstrip())
                i += 1

        done, dump = {}, []
        for name, where, value in vars:
            if name in done:
                continue
            done[name] = 1
            if value is not __UNDEF__:
                if where == 'global':
                    name = 'global ' + name
                elif where != 'local':
                    name = where + name.split('.')[-1]
                dump.append('%s = %s' % (name, pydoc.text.repr(value)))
            else:
                dump.append(name + ' undefined')

        rows.append('\n'.join(dump))
        frames.append('\n%s\n' % '\n'.join(rows))

    exception = ['%s: %s' % (str(etype), str(evalue))]
    for name in dir(evalue):
        value = pydoc.text.repr(getattr(evalue, name))
        exception.append('\n%s%s = %s' % (' ' * 4, name, value))

    return head + ''.join(frames) + ''.join(exception) + '''

The above is a description of an error in a Python program.  Here is
the original traceback:

%s
''' % ''.join(traceback.format_exception(etype, evalue, etb))


class Hook:
    """A hook to replace sys.excepthook"""

    def __init__(self, logdir=None, context=5, file=None):
        self.logdir = logdir            # log tracebacks to files if not None
        self.context = context          # number of source code lines per frame
        self.file = file or sys.stdout  # place to send the output

    def __call__(self, etype, evalue, etb):
        self.handle((etype, evalue, etb))

    def handle(self, info=None):
        info = info or sys.exc_info()

        formatter = text

        try:
            doc = formatter(info, self.context)
        except:                         # just in case something goes wrong
            doc = ''.join(traceback.format_exception(*info))

        self.file.write(doc + '\n')

        if self.logdir is not None:
            suffix = '.txt'
            (fd, path) = tempfile.mkstemp(suffix=suffix, dir=self.logdir)

            try:
                with os.fdopen(fd, 'w') as file:
                    file.write(doc)
                msg = '%s contains the description of this error.' % path
            except:
                msg = 'Tried to save traceback to %s, but failed.' % path

            self.file.write(msg + '\n')

        try:
            self.file.flush()
        except:
            pass


handler = Hook().handle


def enable(logdir=None, context=5):
    """Install an exception handler that sends verbose tracebacks to STDOUT."""
    sys.excepthook = Hook(logdir=logdir, context=context)

Hi there - it looks like you are initializing tracebackplus with a single, unnamed argumet (5).

Here is the init definition:

def __init__(self, logdir=None, context=5, file=None):
        self.logdir = logdir            # log tracebacks to files if not None
        self.context = context          # number of source code lines per frame
        self.file = file or sys.stdout  # place to send the output

I would use tracebackplus.enable(context=5) instead of tracebackplus.enable(5) as it is mistaking context for logdir.

My bad, ta!

ps. Looking at the original cgitb code -- apparently it is indeed not too hard to self-maintain: in fact, there was a tiny little change between v.3.8 and 3.11, after what apparently python devs got exhausted and decided that that would be too much for the day