Fancy logformatter to format exceptions better

This is a bit of an experimental change at this point; the idea is to see if it
helps us track down where our stack overflows are coming from by logging the
stack when the exception was caught and turned into a Failure. (We'll also need
edf2704420).

If we deploy this, we'll be able to enable it via the log config yaml.
This commit is contained in:
Richard van der Hoff 2017-10-09 17:44:42 +01:00
parent 0eeaa25694
commit 3cc852d339

View File

@ -0,0 +1,43 @@
# -*- coding: utf-8 -*-
# Copyright 2017 New Vector Ltd
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import StringIO
import logging
import traceback
class LogFormatter(logging.Formatter):
"""Log formatter which gives more detail for exceptions
This is the same as the standard log formatter, except that when logging
exceptions [typically via log.foo("msg", exc_info=1)], it prints the
sequence that led up to the point at which the exception was caught.
(Normally only stack frames between the point the exception was raised and
where it was caught are logged).
"""
def __init__(self, *args, **kwargs):
super(LogFormatter, self).__init__(*args, **kwargs)
def formatException(self, ei):
sio = StringIO.StringIO()
sio.write("Capture point (most recent call last):\n")
traceback.print_stack(ei[2].tb_frame.f_back, None, sio)
traceback.print_exception(ei[0], ei[1], ei[2], None, sio)
s = sio.getvalue()
sio.close()
if s[-1:] == "\n":
s = s[:-1]
return s