# -*- coding: utf-8 -*-
#
# Licensed to the Apache Software Foundation (ASF) under one
# or more contributor license agreements. See the NOTICE file
# distributed with this work for additional information
# regarding copyright ownership. The ASF licenses this file
# to you 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 logging
import sys
import warnings
from contextlib import contextmanager
from logging import Handler, StreamHandler
[docs]class LoggingMixin:
"""
Convenience super-class to have a logger configured with the class name
"""
def __init__(self, context=None):
self._set_context(context)
# We want to deprecate the logger property in Airflow 2.0
# The log property is the de facto standard in most programming languages
@property
def logger(self):
warnings.warn(
'Initializing logger for {} using logger(), which will '
'be replaced by .log in Airflow 2.0'.format(
self.__class__.__module__ + '.' + self.__class__.__name__
),
DeprecationWarning
)
return self.log
@property
def log(self):
try:
return self._log
except AttributeError:
self._log = logging.root.getChild(
self.__class__.__module__ + '.' + self.__class__.__name__
)
return self._log
def _set_context(self, context):
if context is not None:
set_context(self.log, context)
# TODO: Formally inherit from io.IOBase
class StreamLogWriter:
encoding = False
"""
Allows to redirect stdout and stderr to logger
"""
def __init__(self, logger, level):
"""
:param log: The log level method to write to, ie. log.debug, log.warning
:return:
"""
self.logger = logger
self.level = level
self._buffer = str()
@property
def closed(self):
"""
Returns False to indicate that the stream is not closed (as it will be
open for the duration of Airflow's lifecycle).
For compatibility with the io.IOBase interface.
"""
return False
def write(self, message):
"""
Do whatever it takes to actually log the specified logging record
:param message: message to log
"""
if not message.endswith("\n"):
self._buffer += message
else:
self._buffer += message
self.logger.log(self.level, self._buffer.rstrip())
self._buffer = str()
def flush(self):
"""
Ensure all logging output has been flushed
"""
if len(self._buffer) > 0:
self.logger.log(self.level, self._buffer)
self._buffer = str()
def isatty(self):
"""
Returns False to indicate the fd is not connected to a tty(-like) device.
For compatibility reasons.
"""
return False
class RedirectStdHandler(StreamHandler):
"""
This class is like a StreamHandler using sys.stderr/stdout, but always uses
whatever sys.stderr/stderr is currently set to rather than the value of
sys.stderr/stdout at handler construction time.
"""
def __init__(self, stream):
if not isinstance(stream, str):
raise Exception("Cannot use file like objects. Use 'stdout' or 'stderr'"
" as a str and without 'ext://'.")
self._use_stderr = True
if 'stdout' in stream:
self._use_stderr = False
# StreamHandler tries to set self.stream
Handler.__init__(self)
@property
def stream(self):
if self._use_stderr:
return sys.stderr
return sys.stdout
@contextmanager
def redirect_stdout(logger, level):
writer = StreamLogWriter(logger, level)
try:
sys.stdout = writer
yield
finally:
sys.stdout = sys.__stdout__
@contextmanager
def redirect_stderr(logger, level):
writer = StreamLogWriter(logger, level)
try:
sys.stderr = writer
yield
finally:
sys.stderr = sys.__stderr__
def set_context(logger, value):
"""
Walks the tree of loggers and tries to set the context for each handler
:param logger: logger
:param value: value to set
"""
_logger = logger
while _logger:
for handler in _logger.handlers:
try:
handler.set_context(value)
except AttributeError:
# Not all handlers need to have context passed in so we ignore
# the error when handlers do not have set_context defined.
pass
if _logger.propagate is True:
_logger = _logger.parent
else:
_logger = None