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
# 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.

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")
    from ignite.engine import Engine
    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