Python traceback.extract_tb() Examples

def test_future_traceback(self):
        @return_future
        @gen.engine
        def f(callback):
            yield gen.Task(self.io_loop.add_callback)
            try:
                1 / 0
            except ZeroDivisionError:
                self.expected_frame = traceback.extract_tb(
                    sys.exc_info()[2], limit=1)[0]
                raise
        try:
            yield f()
            self.fail("didn't get expected exception")
        except ZeroDivisionError:
            tb = traceback.extract_tb(sys.exc_info()[2])
            self.assertIn(self.expected_frame, tb)

# The following series of classes demonstrate and test various styles
# of use, with and without generators and futures. 

def find_deepest_user_frame(tb):
    """
    Find the deepest stack frame that is not part of SCons.

    Input is a "pre-processed" stack trace in the form
    returned by traceback.extract_tb() or traceback.extract_stack()
    """
    
    tb.reverse()

    # find the deepest traceback frame that is not part
    # of SCons:
    for frame in tb:
        filename = frame[0]
        if string.find(filename, os.sep+'SCons'+os.sep) == -1:
            return frame
    return tb[0] 

def showtraceback(self):
        """Display the exception that just occurred.

        We remove the first stack item because it is our own code.

        The output is written by self.write(), below.

        """
        try:
            type, value, tb = sys.exc_info()
            sys.last_type = type
            sys.last_value = value
            sys.last_traceback = tb
            tblist = traceback.extract_tb(tb)
            del tblist[:1]
            list = traceback.format_list(tblist)
            if list:
                list.insert(0, "Traceback (most recent call last):\n")
            list[len(list):] = traceback.format_exception_only(type, value)
        finally:
            tblist = tb = None
        map(self.write, list) 

def SConscript_exception(file=sys.stderr):
    """Print an exception stack trace just for the SConscript file(s).
    This will show users who have Python errors where the problem is,
    without cluttering the output with all of the internal calls leading
    up to where we exec the SConscript."""
    exc_type, exc_value, exc_tb = sys.exc_info()
    tb = exc_tb
    while tb and stack_bottom not in tb.tb_frame.f_locals:
        tb = tb.tb_next
    if not tb:
        # We did not find our exec statement, so this was actually a bug
        # in SCons itself.  Show the whole stack.
        tb = exc_tb
    stack = traceback.extract_tb(tb)
    try:
        type = exc_type.__name__
    except AttributeError:
        type = str(exc_type)
        if type[:11] == "exceptions.":
            type = type[11:]
    file.write('%s: %s:\n' % (type, exc_value))
    for fname, line, func, text in stack:
        file.write('  File "%s", line %d:\n' % (fname, line))
        file.write('    %s\n' % text) 

def hook_exceptions(self, logger: logging.RootLogger) -> None:
        """Format excetion traceback.
        
        Parameters:
            logger:
                The logger for logging exceptions.
        """

        def _hook(exc_type, value, exc_tb) -> None:
            nest_dir = os.path.dirname(os.path.abspath(__file__))
            traceback_str = ''
            idx = 0
            for file_name, line_number, func_name, text in traceback.extract_tb(exc_tb)[1:]:
                # skip Nest-related tracebacks to make it more readable
                if os.path.dirname(os.path.abspath(file_name)) == nest_dir:
                    continue
                idx += 1
                traceback_str += '\n  [%d] File "%s", line %d, in function "%s"\n    %s' % \
                    (idx, file_name, line_number, func_name, text)
            if traceback_str != '':
                traceback_str = 'Traceback: ' + traceback_str
            logger.critical('Exception occurred during resolving:\nType: %s\nMessage: %s\n%s' % \
                (exc_type.__name__, value, traceback_str))

        sys.excepthook = _hook 

def extra_serializer(obj: Any) -> Union[int, str, List[Any], Dict[str, Any]]:
    """JSON serializer for objects not serializable by default json code"""

    if isinstance(obj, datetime.datetime):
        return dtutil.dt2ts(obj)
    if isinstance(obj, bytes):
        return obj.decode('utf-8')
    if isinstance(obj, decimal.Decimal):
        return obj.to_eng_string()
    if isinstance(obj, (set, KeysView)):
        return list(obj)
    if isinstance(obj, Exception):
        stack = traceback.extract_tb(obj.__traceback__)
        return traceback.format_list(stack)
    if hasattr(obj, 'to_dict'):
        return obj.to_dict()
    if hasattr(obj, '__attrs_attrs__'):
        val: Dict[str, Any] = {}
        for a in obj.__attrs_attrs__:
            val[a.name] = getattr(obj, a.name)
        return val
    raise TypeError('Type {t} not serializable - {obj}'.format(t=type(obj), obj=obj)) 

def showtraceback(self, *args, **kwargs):
        """Display the exception that just occurred."""
        # Override for avoid using sys.excepthook PY-12600
        try:
            type, value, tb = sys.exc_info()
            sys.last_type = type
            sys.last_value = value
            sys.last_traceback = tb
            tblist = traceback.extract_tb(tb)
            del tblist[:1]
            lines = traceback.format_list(tblist)
            if lines:
                lines.insert(0, "Traceback (most recent call last):\n")
            lines.extend(traceback.format_exception_only(type, value))
        finally:
            tblist = tb = None
        sys.stderr.write(''.join(lines)) 

def test_future_traceback(self):
        @return_future
        @gen.engine
        def f(callback):
            yield gen.Task(self.io_loop.add_callback)
            try:
                1 / 0
            except ZeroDivisionError:
                self.expected_frame = traceback.extract_tb(
                    sys.exc_info()[2], limit=1)[0]
                raise
        try:
            yield f()
            self.fail("didn't get expected exception")
        except ZeroDivisionError:
            tb = traceback.extract_tb(sys.exc_info()[2])
            self.assertIn(self.expected_frame, tb)

# The following series of classes demonstrate and test various styles
# of use, with and without generators and futures. 

def test_future_traceback(self):
        @return_future
        @gen.engine
        def f(callback):
            yield gen.Task(self.io_loop.add_callback)
            try:
                1 / 0
            except ZeroDivisionError:
                self.expected_frame = traceback.extract_tb(
                    sys.exc_info()[2], limit=1)[0]
                raise
        try:
            yield f()
            self.fail("didn't get expected exception")
        except ZeroDivisionError:
            tb = traceback.extract_tb(sys.exc_info()[2])
            self.assertIn(self.expected_frame, tb)

# The following series of classes demonstrate and test various styles
# of use, with and without generators and futures. 

def print_small_exception(start_after):
    type, value, traceback_ = sys.exc_info()

    tb = traceback.extract_tb(traceback_)
    index = 0

    for i, trace in enumerate(tb):
        if trace[2] == start_after:
            index = i + 1
            break

    lines = traceback.format_list(tb[index:])
    lines += traceback.format_exception_only(type, value)

    for line in lines:
        sys.stderr.write(line)

    sys.stderr.write("\n") 

def log(self, cause=None, do_message=True, custom_msg=None):
        """
        Loads exception data from the current exception frame - should be called inside the except block
        :return:
        """
        message = error_message(self, cause=cause)
        exc_type, exc_value, exc_traceback = sys.exc_info()
        traceback_formatted = traceback.format_exc()
        traceback_val = traceback.extract_tb(exc_traceback)

        md5 = hashlib.md5(traceback_formatted.encode('utf-8')).hexdigest()

        if md5 in self._db:
            # self.logger.debug('Exception trace logged: %s' % md5)
            return

        if custom_msg is not None and cause is not None:
            self.logger.debug('%s : %s' % (custom_msg, cause))
        elif custom_msg is not None:
            self.logger.debug(custom_msg)
        elif cause is not None:
            self.logger.debug('%s' % cause)

        self.logger.debug(traceback_formatted)
        self._db.add(md5) 

def showtraceback(self, *args, **kwargs):
        """Display the exception that just occurred.

        We remove the first stack item because it is our own code.

        The output is written by self.write(), below.

        """
        try:
            type, value, tb = sys.exc_info()
            sys.last_type = type
            sys.last_value = value
            sys.last_traceback = tb
            tblist = traceback.extract_tb(tb)
            del tblist[:1]
            list = traceback.format_list(tblist)
            if list:
                list.insert(0, "Traceback (most recent call last):\n")
            list[len(list):] = traceback.format_exception_only(type, value)
        finally:
            tblist = tb = None
        map(self.write, list) 

def find_deepest_user_frame(tb):
    """
    Find the deepest stack frame that is not part of SCons.

    Input is a "pre-processed" stack trace in the form
    returned by traceback.extract_tb() or traceback.extract_stack()
    """

    tb.reverse()

    # find the deepest traceback frame that is not part
    # of SCons:
    for frame in tb:
        filename = frame[0]
        if filename.find(os.sep+'SCons'+os.sep) == -1:
            return frame
    return tb[0] 

def doTraceback(self, module):
        try:
            module.do_raise()
        except:
            tb = sys.exc_info()[2].tb_next

            f,lno,n,line = extract_tb(tb, 1)[0]
            self.assertEqual(line, raise_src.strip())

            f,lno,n,line = extract_stack(tb.tb_frame, 1)[0]
            self.assertEqual(line, raise_src.strip())

            s = StringIO.StringIO()
            print_tb(tb, 1, s)
            self.assertTrue(s.getvalue().endswith(raise_src))
        else:
            raise AssertionError("This ought to be impossible") 

def showtraceback(self):
        """Display the exception that just occurred.

        We remove the first stack item because it is our own code.

        The output is written by self.write(), below.

        """
        try:
            type, value, tb = sys.exc_info()
            sys.last_type = type
            sys.last_value = value
            sys.last_traceback = tb
            tblist = traceback.extract_tb(tb)
            del tblist[:1]
            list = traceback.format_list(tblist)
            if list:
                list.insert(0, "Traceback (most recent call last):\n")
            list[len(list):] = traceback.format_exception_only(type, value)
        finally:
            tblist = tb = None
        map(self.write, list) 

def handle_exception(type, value, tb):
    # Print stack trace.
    info = traceback.format_exception(type, value, tb)
    logging.error(''.join(info))

    # Get local variables.
    while True:
        if not tb.tb_next:
            break
        next_frame = traceback.extract_tb(tb)[1]
        if next_frame.filename.startswith('/'): # not our code
            break
        tb = tb.tb_next
    local_vars = tb.tb_frame.f_locals

    # Start kernel.
    import os
    pid = os.fork()
    if pid == 0:
        open(f"{os.environ['HOME']}/.pynt", 'a').close()
        import IPython
        IPython.start_kernel(user_ns=local_vars)
    os.waitpid(pid, 0) 

def showtraceback(self):
        """Display the exception that just occurred.

        We remove the first stack item because it is our own code.

        The output is written by self.write(), below.

        """
        try:
            type, value, tb = sys.exc_info()
            sys.last_type = type
            sys.last_value = value
            sys.last_traceback = tb
            tblist = traceback.extract_tb(tb)
            del tblist[:1]
            list = traceback.format_list(tblist)
            if list:
                list.insert(0, "Traceback (most recent call last):\n")
            list[len(list):] = traceback.format_exception_only(type, value)
        finally:
            tblist = tb = None
        map(self.write, list) 

def test_future_traceback(self):
        @return_future
        @gen.engine
        def f(callback):
            yield gen.Task(self.io_loop.add_callback)
            try:
                1 / 0
            except ZeroDivisionError:
                self.expected_frame = traceback.extract_tb(
                    sys.exc_info()[2], limit=1)[0]
                raise
        try:
            yield f()
            self.fail("didn't get expected exception")
        except ZeroDivisionError:
            tb = traceback.extract_tb(sys.exc_info()[2])
            self.assertIn(self.expected_frame, tb)

# The following series of classes demonstrate and test various styles
# of use, with and without generators and futures. 

def doTraceback(self, module):
        try:
            module.do_raise()
        except:
            tb = sys.exc_info()[2].tb_next

            f,lno,n,line = extract_tb(tb, 1)[0]
            self.assertEqual(line, raise_src.strip())

            f,lno,n,line = extract_stack(tb.tb_frame, 1)[0]
            self.assertEqual(line, raise_src.strip())

            s = StringIO.StringIO()
            print_tb(tb, 1, s)
            self.assertTrue(s.getvalue().endswith(raise_src))
        else:
            raise AssertionError("This ought to be impossible") 

def format_exc(limit=None, exception=None, tb_list=None):
    """
    This is like print_exc(limit) but returns a string instead of printing to a
    file.
    """
    result = ["Traceback (most recent call last):\n"]
    if exception is None:
        exception = get_context_with_traceback(get_async_context()).exception

    if tb_list is None:
        tb_list = extract_tb(limit)

    if tb_list:
        result.extend(traceback.format_list(tb_list))
        result.extend(traceback.format_exception_only(exception.__class__,
                                                      exception))
        return result
    else:
        return None 

def showtraceback(self):
        """Display the exception that just occurred.

        We remove the first stack item because it is our own code.

        The output is written by self.write(), below.

        """
        try:
            type, value, tb = sys.exc_info()
            sys.last_type = type
            sys.last_value = value
            sys.last_traceback = tb
            tblist = traceback.extract_tb(tb)
            del tblist[:1]
            list = traceback.format_list(tblist)
            if list:
                list.insert(0, "Traceback (most recent call last):\n")
            list[len(list):] = traceback.format_exception_only(type, value)
        finally:
            tblist = tb = None
        map(self.write, list) 

def output_wechat():
    from . import config
    exc_type, exc_value, exc_tb = sys.exc_info()
    exc_type_msg = exc_type.__name__ if exc_type else exc_type
    exc_tbs = sorted(
        [e for e in traceback.extract_tb(exc_tb)],
        key=lambda e: len(e.filename))
    exc_tb = exc_tbs[0] if exc_tbs else None
    exc_tb = exc_tb if exc_tb else None
    for user in eval(config['base']['maintainer']):
        send_msg(
            user,
            config['template']['url'],
            exc_type_msg,
            str(exc_value) if exc_value else None,
            *exc_tb
        ) if exc_type_msg or exc_value or exc_tb else None 

def print_exception():
    import linecache
    linecache.checkcache()
    flush_stdout()
    efile = sys.stderr
    typ, val, tb = excinfo = sys.exc_info()
    sys.last_type, sys.last_value, sys.last_traceback = excinfo
    tbe = traceback.extract_tb(tb)
    print>>efile, '\nTraceback (most recent call last):'
    exclude = ("run.py", "rpc.py", "threading.py", "Queue.py",
               "RemoteDebugger.py", "bdb.py")
    cleanup_traceback(tbe, exclude)
    traceback.print_list(tbe, file=efile)
    lines = traceback.format_exception_only(typ, val)
    for line in lines:
        print>>efile, line, 

def doTraceback(self, module):
        try:
            module.do_raise()
        except:
            tb = sys.exc_info()[2].tb_next

            f,lno,n,line = extract_tb(tb, 1)[0]
            self.assertEqual(line, raise_src.strip())

            f,lno,n,line = extract_stack(tb.tb_frame, 1)[0]
            self.assertEqual(line, raise_src.strip())

            s = StringIO.StringIO()
            print_tb(tb, 1, s)
            self.assertTrue(s.getvalue().endswith(raise_src))
        else:
            raise AssertionError("This ought to be impossible") 

def showtraceback(self):
        """Display the exception that just occurred.

        We remove the first stack item because it is our own code.

        The output is written by self.write(), below.

        """
        try:
            type, value, tb = sys.exc_info()
            sys.last_type = type
            sys.last_value = value
            sys.last_traceback = tb
            tblist = traceback.extract_tb(tb)
            del tblist[:1]
            list = traceback.format_list(tblist)
            if list:
                list.insert(0, "Traceback (most recent call last):\n")
            list[len(list):] = traceback.format_exception_only(type, value)
        finally:
            tblist = tb = None
        map(self.write, list) 

def traceback_get_exception(num = -1):

    # build error message
    exception_string = ''.join(traceback.format_exception_only(sys.exc_type, hasattr(sys, 'exc_value') and sys.exc_value or 'Unknown'))

    # extract error location from traceback
    if hasattr(sys, 'exc_traceback'):
        (filename, line_number, function_name, text) = traceback.extract_tb(sys.exc_traceback)[num]
    else:
        (filename, line_number, function_name, text) = ('-', '-', '-', '-')

    error = {
        'message': exception_string,
        'location': {
            'filename': filename,
            'line_number': line_number,
            'function_name': function_name,
            'text': text,
            }
    }

    return error 

def check_errors(fn):
    def wrapper(*args, **kwargs):
        global _exception
        try:
            fn(*args, **kwargs)
        except Exception:
            _exception = sys.exc_info()

            et, ev, tb = _exception

            if getattr(ev, 'filename', None) is None:
                # get the filename from the last item in the stack
                filename = traceback.extract_tb(tb)[-1][0]
            else:
                filename = ev.filename

            if filename not in _error_files:
                _error_files.append(filename)

            raise

    return wrapper 

def SConscript_exception(file=sys.stderr):
    """Print an exception stack trace just for the SConscript file(s).
    This will show users who have Python errors where the problem is,
    without cluttering the output with all of the internal calls leading
    up to where we exec the SConscript."""
    exc_type, exc_value, exc_tb = sys.exc_info()
    tb = exc_tb
    while tb and stack_bottom not in tb.tb_frame.f_locals:
        tb = tb.tb_next
    if not tb:
        # We did not find our exec statement, so this was actually a bug
        # in SCons itself.  Show the whole stack.
        tb = exc_tb
    stack = traceback.extract_tb(tb)
    try:
        type = exc_type.__name__
    except AttributeError:
        type = str(exc_type)
        if type[:11] == "exceptions.":
            type = type[11:]
    file.write('%s: %s:\n' % (type, exc_value))
    for fname, line, func, text in stack:
        file.write('  File "%s", line %d:\n' % (fname, line))
        file.write('    %s\n' % text) 

def find_deepest_user_frame(tb):
    """
    Find the deepest stack frame that is not part of SCons.

    Input is a "pre-processed" stack trace in the form
    returned by traceback.extract_tb() or traceback.extract_stack()
    """

    tb.reverse()

    # find the deepest traceback frame that is not part
    # of SCons:
    for frame in tb:
        filename = frame[0]
        if filename.find(os.sep+'SCons'+os.sep) == -1:
            return frame
    return tb[0] 

def import_symbol(import_path, setting_name):
    """
    Import a class or function by name.
    """
    mod_name, class_name = import_path.rsplit('.', 1)

    # import module
    try:
        mod = import_module(mod_name)
        cls = getattr(mod, class_name)
    except ImportError as e:
        __, __, exc_traceback = sys.exc_info()
        frames = traceback.extract_tb(exc_traceback)
        if len(frames) > 1 and any('importlib' not in f[0] for f in frames[1:]):
            raise   # import error is a level deeper.

        raise ImproperlyConfigured("{0} does not point to an existing class: {1}".format(setting_name, import_path))
    except AttributeError:
        raise ImproperlyConfigured("{0} does not point to an existing class: {1}".format(setting_name, import_path))

    return cls