#!/usr/bin/env python
# -*- coding: utf-8 -*-
#############################################################################
# Copyright Kitware Inc.
#
# 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 cherrypy
import logging
import re
import time
LoggingFilters = []
SingletonRegexLoggingFilter = None
[docs]class RegexLoggingFilter(logging.Filter):
"""
Check log messages against a list of compiled regular expressions. If any
of them match, throttle logs.
"""
def filter(self, record):
if getattr(record, 'logging.filtered', None) is not None:
return getattr(record, 'logging.filtered')
setattr(record, 'logging.filtered', True)
msg = record.getMessage()
for filter in LoggingFilters:
if filter['re'].search(msg):
filter['count'] += 1
if ((filter['frequency'] and
filter['count'] >= filter['frequency']) or
(filter['duration'] and
time.time() - filter.get('timestamp', 0) > filter['duration'])):
if filter['count'] > 1:
record.msg += ' (%d similar messages)' % filter['count']
filter['count'] = 0
filter['timestamp'] = time.time()
return True
setattr(record, 'logging.filtered', False)
return False
return True
[docs]def addLoggingFilter(regex, frequency=None, duration=None):
"""
Add a regular expression to the logging filter. If the regular expression
matches a registered regex exactly, just update the frequency value.
:param regex: a regular expression to match against log messages. For
matching cherrypy endpoint logging, this should probably be something
like 'GET /api/v1/item/[0-9a-fA-F]+/download[/ ?#]'. More generally,
a value like GET (/[^/ ?#]+)*/item/[^/ ?#]+/download[/ ?#] would be
agnostic to the api_root.
:param frequency: either None to never log matching log messages, or an
integer, where one log message is emitted out of the specified number.
:param duration: either None to not log based on elapsed time, or a float
value of seconds between logging.
"""
# Always make sure that cherrypy is using our logging filter class. This
# is done as a singleton so that addFilter will not duplicate the filter.
# By doing this here, the import order doesn't matter, and additional
# cherrypy handlers can be added after import, provided that
# addLoggingFilter is called after the new logging handlers were added.
global SingletonRegexLoggingFilter
if not SingletonRegexLoggingFilter:
SingletonRegexLoggingFilter = RegexLoggingFilter()
for handler in cherrypy.log.access_log.handlers:
handler.addFilter(SingletonRegexLoggingFilter)
# Now add or adjust the regex filter.
newFilter = None
for filter in LoggingFilters:
if filter['regex'] == regex:
newFilter = filter
if not newFilter:
newFilter = {
'regex': regex,
're': re.compile(regex),
'count': 0
}
LoggingFilters.append(newFilter)
newFilter['frequency'] = frequency
newFilter['duration'] = duration
[docs]def removeLoggingFilter(regex):
"""
Remove a regular expression from the logging filter.
:param regex: the regular expression to remove.
:returns: True if a filter was removed.
"""
for idx in range(len(LoggingFilters)):
if LoggingFilters[idx]['regex'] == regex:
LoggingFilters[idx:idx + 1] = []
return True
return False