Source code for ops.log

# 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
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# 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