9ad7ec6f82
Now that the REVERT and REVERT_FAILURE states can produce results or failure objects we need to take that into account in listeners that were not expecting those states to produce anything; this change adjusts the built-in listeners so that they now handle these states and the results they produce. Also removes some no longer needed py2.6 code used in the logging listener, as that is not needed anymore since we dropped py2.6 support. Change-Id: I0d0a9759648b2a2f27a97c68e19c7cdb6375a4f2
233 lines
8.2 KiB
Python
233 lines
8.2 KiB
Python
# -*- coding: utf-8 -*-
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# Copyright (C) 2013 Yahoo! Inc. All Rights Reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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from __future__ import absolute_import
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import abc
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from debtcollector import moves
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from oslo_utils import excutils
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import six
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from taskflow import logging
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from taskflow import states
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from taskflow.types import failure
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from taskflow.types import notifier
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LOG = logging.getLogger(__name__)
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#: These states will results be usable, other states do not produce results.
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FINISH_STATES = (states.FAILURE, states.SUCCESS,
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states.REVERTED, states.REVERT_FAILURE)
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#: What is listened for by default...
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DEFAULT_LISTEN_FOR = (notifier.Notifier.ANY,)
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def _task_matcher(details):
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"""Matches task details emitted."""
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if not details:
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return False
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if 'task_name' in details and 'task_uuid' in details:
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return True
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return False
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def _retry_matcher(details):
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"""Matches retry details emitted."""
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if not details:
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return False
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if 'retry_name' in details and 'retry_uuid' in details:
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return True
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return False
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def _bulk_deregister(notifier, registered, details_filter=None):
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"""Bulk deregisters callbacks associated with many states."""
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while registered:
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state, cb = registered.pop()
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notifier.deregister(state, cb,
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details_filter=details_filter)
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def _bulk_register(watch_states, notifier, cb, details_filter=None):
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"""Bulk registers a callback associated with many states."""
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registered = []
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try:
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for state in watch_states:
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if not notifier.is_registered(state, cb,
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details_filter=details_filter):
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notifier.register(state, cb,
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details_filter=details_filter)
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registered.append((state, cb))
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except ValueError:
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with excutils.save_and_reraise_exception():
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_bulk_deregister(notifier, registered,
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details_filter=details_filter)
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else:
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return registered
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class Listener(object):
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"""Base class for listeners.
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A listener can be attached to an engine to do various actions on flow and
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atom state transitions. It implements the context manager protocol to be
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able to register and unregister with a given engine automatically when a
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context is entered and when it is exited.
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To implement a listener, derive from this class and override
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``_flow_receiver`` and/or ``_task_receiver`` and/or ``_retry_receiver``
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methods (in this class, they do nothing).
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"""
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def __init__(self, engine,
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task_listen_for=DEFAULT_LISTEN_FOR,
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flow_listen_for=DEFAULT_LISTEN_FOR,
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retry_listen_for=DEFAULT_LISTEN_FOR):
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if not task_listen_for:
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task_listen_for = []
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if not retry_listen_for:
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retry_listen_for = []
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if not flow_listen_for:
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flow_listen_for = []
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self._listen_for = {
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'task': list(task_listen_for),
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'retry': list(retry_listen_for),
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'flow': list(flow_listen_for),
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}
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self._engine = engine
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self._registered = {}
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def _flow_receiver(self, state, details):
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pass
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def _task_receiver(self, state, details):
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pass
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def _retry_receiver(self, state, details):
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pass
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def deregister(self):
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if 'task' in self._registered:
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_bulk_deregister(self._engine.atom_notifier,
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self._registered['task'],
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details_filter=_task_matcher)
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del self._registered['task']
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if 'retry' in self._registered:
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_bulk_deregister(self._engine.atom_notifier,
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self._registered['retry'],
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details_filter=_retry_matcher)
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del self._registered['retry']
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if 'flow' in self._registered:
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_bulk_deregister(self._engine.notifier,
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self._registered['flow'])
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del self._registered['flow']
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def register(self):
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if 'task' not in self._registered:
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self._registered['task'] = _bulk_register(
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self._listen_for['task'], self._engine.atom_notifier,
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self._task_receiver, details_filter=_task_matcher)
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if 'retry' not in self._registered:
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self._registered['retry'] = _bulk_register(
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self._listen_for['retry'], self._engine.atom_notifier,
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self._retry_receiver, details_filter=_retry_matcher)
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if 'flow' not in self._registered:
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self._registered['flow'] = _bulk_register(
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self._listen_for['flow'], self._engine.notifier,
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self._flow_receiver)
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def __enter__(self):
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self.register()
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return self
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def __exit__(self, type, value, tb):
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try:
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self.deregister()
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except Exception:
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# Don't let deregistering throw exceptions
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LOG.warn("Failed deregistering listeners from engine %s",
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self._engine, exc_info=True)
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# TODO(harlowja): remove in 0.7 or later...
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ListenerBase = moves.moved_class(Listener, 'ListenerBase', __name__,
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version="0.6", removal_version="2.0")
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@six.add_metaclass(abc.ABCMeta)
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class DumpingListener(Listener):
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"""Abstract base class for dumping listeners.
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This provides a simple listener that can be attached to an engine which can
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be derived from to dump task and/or flow state transitions to some target
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backend.
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To implement your own dumping listener derive from this class and
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override the ``_dump`` method.
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"""
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@abc.abstractmethod
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def _dump(self, message, *args, **kwargs):
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"""Dumps the provided *templated* message to some output."""
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def _flow_receiver(self, state, details):
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self._dump("%s has moved flow '%s' (%s) into state '%s'"
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" from state '%s'", self._engine, details['flow_name'],
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details['flow_uuid'], state, details['old_state'])
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def _task_receiver(self, state, details):
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if state in FINISH_STATES:
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result = details.get('result')
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exc_info = None
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was_failure = False
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if isinstance(result, failure.Failure):
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if result.exc_info:
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exc_info = tuple(result.exc_info)
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was_failure = True
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self._dump("%s has moved task '%s' (%s) into state '%s'"
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" from state '%s' with result '%s' (failure=%s)",
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self._engine, details['task_name'],
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details['task_uuid'], state, details['old_state'],
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result, was_failure, exc_info=exc_info)
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else:
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self._dump("%s has moved task '%s' (%s) into state '%s'"
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" from state '%s'", self._engine, details['task_name'],
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details['task_uuid'], state, details['old_state'])
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# TODO(harlowja): remove in 0.7 or later...
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class LoggingBase(moves.moved_class(DumpingListener,
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'LoggingBase', __name__,
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version="0.6", removal_version="2.0")):
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"""Legacy logging base.
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.. deprecated:: 0.6
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This class is **deprecated** and is present for backward
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compatibility **only**, its replacement
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:py:class:`.DumpingListener` should be used going forward.
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"""
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def _dump(self, message, *args, **kwargs):
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self._log(message, *args, **kwargs)
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@abc.abstractmethod
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def _log(self, message, *args, **kwargs):
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"""Logs the provided *templated* message to some output."""
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