# Copyright 2020 Canonical 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.
"""Interface to emit messages to the Juju logging system."""
import logging
import sys
import typing
if typing.TYPE_CHECKING:
from types import TracebackType
from typing import Type
from ops.model import _ModelBackend # pyright: reportPrivateUsage=false
[docs]class JujuLogHandler(logging.Handler):
"""A handler for sending logs to Juju via juju-log."""
def __init__(self, model_backend: "_ModelBackend", level: int = logging.DEBUG):
super().__init__(level)
self.model_backend = model_backend
[docs] def emit(self, record: logging.LogRecord):
"""Send the specified logging record to the Juju backend.
This method is not used directly by the Operator Framework code, but by
:class:`logging.Handler` itself as part of the logging machinery.
"""
self.model_backend.juju_log(record.levelname, self.format(record))
[docs]def setup_root_logging(model_backend: "_ModelBackend", debug: bool = False):
"""Setup python logging to forward messages to juju-log.
By default, logging is set to DEBUG level, and messages will be filtered by Juju.
Charmers can also set their own default log level with::
logging.getLogger().setLevel(logging.INFO)
Args:
model_backend: a ModelBackend to use for juju-log
debug: if True, write logs to stderr as well as to juju-log.
"""
logger = logging.getLogger()
logger.setLevel(logging.DEBUG)
logger.addHandler(JujuLogHandler(model_backend))
if debug:
handler = logging.StreamHandler()
formatter = logging.Formatter('%(asctime)s %(levelname)-8s %(message)s')
handler.setFormatter(formatter)
logger.addHandler(handler)
def except_hook(etype: "Type[BaseException]", value: BaseException, tb: "TracebackType"):
logger.error(
"Uncaught exception while in charm code:",
exc_info=(etype, value, tb))
sys.excepthook = except_hook