Source code for zfit.util.logging

This module controls the zfit logging.

The base logger for zfit is called `zfit`, and all loggers created by this module
have the form `zfit.XX`, where `XX` is their name.

By default, time, name of the logger and message with the default
colorlog color scheme are printed.


import os

import logging
import colorlog

[docs]def get_logger(name, stdout_level=None, file_level=None, file_name=None): """Get and configure logger. This logger has two handlers: - A stdout handler is always configured with `colorlog`. - A file handler is configured if `file_name` is given. Once it has been configure, it is not necessary to give it to modify its properties. Once the logger has been created, `get_logger` can be called again to modify its log levels, independently for the stream and file handlers. Note: If the logger name doesn't start with "zfit", it is automatically added. Note: Default logging level at first instantiation is WARNING. Arguments: name (str): Name of the logger. stdout_level (int, optional): Logging level for the stream handler. Defaults to `logging.WARNING`. file_level (int, optional): Logging level for the file handler. Defaults to `logging.WARNING`. file_name (str, optional): File to log to. If not given, no file logging is performed. Return: `logging.Logger`: The requested logger. Raise: ValueError if `file_level` has been specified without having configured the output file. """ if not name.startswith('zfit'): name = 'zfit.{}'.format(name.rstrip('.')) if stdout_level is None: stdout_level = logging.WARNING format_stream = ("%(asctime)s - %(name)s | " "%(log_color)s%(levelname)-8s%(reset)s | " "%(log_color)s%(message)s%(reset)s") format_file = ("%(asctime)s - %(name)s | " "%(levelname)-8s | " "%(message)s") logger = logging.getLogger(name) if not logger.handlers: # Add Stream handler formatter = colorlog.ColoredFormatter(format_stream) stream = logging.StreamHandler() stream.setFormatter(formatter) logger.addHandler(stream) # The first handler is always the stream logger.handlers[0].setLevel(stdout_level) # Now the file handler file_handler = None # Find the file handler for handler in logger.handlers: if isinstance(handler, logging.FileHandler): if not file_name or \ os.path.abspath(file_name) == handler.baseFilename: file_handler = handler break # If requested, create one if file_name and file_handler is None: formatter = colorlog.ColoredFormatter(format_file) file_handler = logging.FileHandler(file_name) file_handler.setFormatter(formatter) logger.addHandler(file_handler) # Set its level if file_level is not None and file_handler is None: raise ValueError("Requested change in file log level but no file logger has been configured") if file_level is None: file_level = logging.WARNING if file_handler is not None: file_handler.setLevel(file_level) # Set the logging level to the lowest level logger_level = min(stdout_level, file_level) logger.setLevel(logger_level) return logger