Source code for monai.handlers.logfile_handler
# Copyright (c) MONAI Consortium
# 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 annotations
import logging
import os
from typing import TYPE_CHECKING
from monai.config import IgniteInfo
from monai.utils import min_version, optional_import
Events, _ = optional_import("ignite.engine", IgniteInfo.OPT_IMPORT_VERSION, min_version, "Events")
if TYPE_CHECKING:
from ignite.engine import Engine
else:
Engine, _ = optional_import("ignite.engine", IgniteInfo.OPT_IMPORT_VERSION, min_version, "Engine")
__all__ = ["LogfileHandler"]
[docs]
class LogfileHandler:
"""
Adds a `logging.FileHandler` to the attached engine's logger when the start event occurs and removes it again when
then completed event occurs.
A handler is needed to remove `FileHandler` object when the complete event occurs so that further runs of different
engines write only to the log files they should, rather than previous files. Multiple handlers can write to the same
file which allows output from train and evaluation engine objects to be condensed in one file. If the given output
directory doesn't exist it will by default be created when the start event occurs. This can be used in conjunction
with `CheckpointSaver` to save a log file to the same destination as the saved checkpoints. Since the handler is
added possibly after other logging events during initialisation, not all logging data will be retained.
Args:
output_dir: directory to save the log file to
filename: name of the file to save log to
loglevel: log level for the handler
formatter: format string for the `logging.Formatter` set for the handler
create_dir: if True, create `output_dir` if it doesn't exist
"""
def __init__(
self,
output_dir: str,
filename: str = "log.txt",
loglevel: int = logging.INFO,
formatter: str = "%(asctime)s %(name)s %(levelname)s: %(message)s",
create_dir: bool = True,
):
self.output_dir: str = output_dir
self.filename: str = filename
self.loglevel: int = loglevel
self.formatter: str = formatter
self.create_dir: bool = create_dir
self.logger: logging.Logger | None = None
self.handler: logging.FileHandler | None = None
def attach(self, engine: Engine) -> None:
self.logger = engine.logger
engine.add_event_handler(Events.STARTED, self._start)
engine.add_event_handler(Events.COMPLETED, self._completed)
def _start(self, engine: Engine) -> None:
if self.create_dir and not os.path.exists(self.output_dir):
os.makedirs(self.output_dir, exist_ok=True)
self.handler = logging.FileHandler(os.path.join(self.output_dir, self.filename))
self.handler.setLevel(self.loglevel)
self.handler.setFormatter(logging.Formatter(self.formatter))
if self.logger is not None:
self.logger.addHandler(self.handler)
else:
raise AttributeError("`self.logger` must not be None in start event")
def _completed(self, engine: Engine) -> None:
if self.logger is not None and self.handler is not None:
self.logger.removeHandler(self.handler)
self.handler.close()
else:
raise AttributeError("`self.logger` and `self.handler` must not be None in complete event")
self.handler = None