Files
deb-python-taskflow/taskflow/listeners/logging.py
Joshua Harlow 42a665d06f Use platform neutral line separator(s)
To at least try to support things like windows it's better
if we can make an attempt to use the platform neutral
characters for line separator(s) where appropriate.

Change-Id: Icc533ed4d4c94f461b7f19600b74146221f17b18
2015-01-12 20:33:51 -08:00

197 lines
8.2 KiB
Python

# -*- coding: utf-8 -*-
# Copyright (C) 2013 Yahoo! Inc. All Rights Reserved.
#
# 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.
from __future__ import absolute_import
import logging as logging_base
import os
import sys
from taskflow.listeners import base
from taskflow import logging
from taskflow import states
from taskflow.types import failure
LOG = logging.getLogger(__name__)
if sys.version_info[0:2] == (2, 6):
_PY26 = True
else:
_PY26 = False
# Fixes this for python 2.6 which was missing the is enabled for method
# when a logger adapter is being used/provided, this will no longer be needed
# when we can just support python 2.7+ (which fixed the lack of this method
# on adapters).
def _isEnabledFor(logger, level):
if _PY26 and isinstance(logger, logging_base.LoggerAdapter):
return logger.logger.isEnabledFor(level)
return logger.isEnabledFor(level)
class LoggingListener(base.DumpingListener):
"""Listener that logs notifications it receives.
It listens for task and flow notifications and writes those notifications
to a provided logger, or logger of its module
(``taskflow.listeners.logging``) if none is provided. The log level
can also be configured, ``logging.DEBUG`` is used by default when none
is provided.
"""
def __init__(self, engine,
task_listen_for=base.DEFAULT_LISTEN_FOR,
flow_listen_for=base.DEFAULT_LISTEN_FOR,
retry_listen_for=base.DEFAULT_LISTEN_FOR,
log=None,
level=logging.DEBUG):
super(LoggingListener, self).__init__(
engine, task_listen_for=task_listen_for,
flow_listen_for=flow_listen_for, retry_listen_for=retry_listen_for)
if not log:
self._logger = LOG
else:
self._logger = log
self._level = level
def _dump(self, message, *args, **kwargs):
self._logger.log(self._level, message, *args, **kwargs)
class DynamicLoggingListener(base.Listener):
"""Listener that logs notifications it receives.
It listens for task and flow notifications and writes those notifications
to a provided logger, or logger of its module
(``taskflow.listeners.logging``) if none is provided. The log level
can *slightly* be configured and ``logging.DEBUG`` or ``logging.WARNING``
(unless overriden via a constructor parameter) will be selected
automatically based on the execution state and results produced.
The following flow states cause ``logging.WARNING`` (or provided
level) to be used:
* ``states.FAILURE``
* ``states.REVERTED``
The following task states cause ``logging.WARNING`` (or provided level)
to be used:
* ``states.FAILURE``
* ``states.RETRYING``
* ``states.REVERTING``
When a task produces a :py:class:`~taskflow.types.failure.Failure` object
as its result (typically this happens when a task raises an exception) this
will **always** switch the logger to use ``logging.WARNING`` (if the
failure object contains a ``exc_info`` tuple this will also be logged to
provide a meaningful traceback).
"""
def __init__(self, engine,
task_listen_for=base.DEFAULT_LISTEN_FOR,
flow_listen_for=base.DEFAULT_LISTEN_FOR,
retry_listen_for=base.DEFAULT_LISTEN_FOR,
log=None, failure_level=logging.WARNING,
level=logging.DEBUG):
super(DynamicLoggingListener, self).__init__(
engine, task_listen_for=task_listen_for,
flow_listen_for=flow_listen_for, retry_listen_for=retry_listen_for)
self._failure_level = failure_level
self._level = level
self._task_log_levels = {
states.FAILURE: self._failure_level,
states.REVERTED: self._failure_level,
states.RETRYING: self._failure_level,
}
self._flow_log_levels = {
states.FAILURE: self._failure_level,
states.REVERTED: self._failure_level,
}
if not log:
self._logger = LOG
else:
self._logger = log
@staticmethod
def _format_failure(fail):
"""Returns a (exc_info, exc_details) tuple about the failure.
The ``exc_info`` tuple should be a standard three element
(exctype, value, traceback) tuple that will be used for further
logging. If a non-empty string is returned for ``exc_details`` it
should contain any string info about the failure (with any specific
details the ``exc_info`` may not have/contain). If the ``exc_info``
tuple is returned as ``None`` then it will cause the logging
system to avoid outputting any traceback information (read
the python documentation on the logger interaction with ``exc_info``
to learn more).
"""
if fail.exc_info:
exc_info = fail.exc_info
exc_details = ''
else:
# When a remote failure occurs (or somehow the failure
# object lost its traceback), we will not have a valid
# exc_info that can be used but we *should* have a string
# version that we can use instead...
exc_info = None
exc_details = "%s%s" % (os.linesep, fail.pformat(traceback=True))
return (exc_info, exc_details)
def _flow_receiver(self, state, details):
"""Gets called on flow state changes."""
level = self._flow_log_levels.get(state, self._level)
self._logger.log(level, "Flow '%s' (%s) transitioned into state '%s'"
" from state '%s'", details['flow_name'],
details['flow_uuid'], state, details.get('old_state'))
def _task_receiver(self, state, details):
"""Gets called on task state changes."""
if 'result' in details and state in base.FINISH_STATES:
# If the task failed, it's useful to show the exception traceback
# and any other available exception information.
result = details.get('result')
if isinstance(result, failure.Failure):
exc_info, exc_details = self._format_failure(result)
self._logger.log(self._failure_level,
"Task '%s' (%s) transitioned into state"
" '%s'%s", details['task_name'],
details['task_uuid'], state, exc_details,
exc_info=exc_info)
else:
# Otherwise, depending on the enabled logging level/state we
# will show or hide results that the task may have produced
# during execution.
level = self._task_log_levels.get(state, self._level)
if (_isEnabledFor(self._logger, self._level)
or state == states.FAILURE):
self._logger.log(level, "Task '%s' (%s) transitioned into"
" state '%s' with result '%s'",
details['task_name'],
details['task_uuid'], state,
result)
else:
self._logger.log(level, "Task '%s' (%s) transitioned into"
" state '%s'", details['task_name'],
details['task_uuid'], state)
else:
# Just a intermediary state, carry on!
level = self._task_log_levels.get(state, self._level)
self._logger.log(level, "Task '%s' (%s) transitioned into state"
" '%s'", details['task_name'],
details['task_uuid'], state)