"""Logging module.
This module produces a `logging.Logger` instance that can log both to stdout (i.e. using print) and
also to an output file. This is especially useful for long or parallelized calculations where
more significant diagnostic outputs are required for debugging and/or record-keeping.
"""
import logging
from logging import DEBUG, INFO, WARNING, ERROR # noqa import these for easier access internally
import sys
[docs]
def get_logger(name='holodeck', level_stream=logging.WARNING, tostr=sys.stdout, tofile=None, level_file=logging.DEBUG):
"""Create a standard logger object which logs to file and or stdout stream.
Parameters
----------
name : str,
Handle for this logger, must be distinct for a distinct logger.
level_stream : int,
Logging level for stream.
tostr : bool,
Log to stdout stream.
tofile : str or `None`,
Filename to log to (turned off if `None`).
level_file : int,
Logging level for file.
Returns
-------
logger : ``logging.Logger`` object,
Logger object to use for logging.
"""
if (tofile is None) and (not tostr):
raise ValueError("Must log to something!")
logger = logging.getLogger(name)
# Make sure handlers don't get duplicated (ipython issue)
while len(logger.handlers) > 0:
logger.handlers.pop()
# Prevents duplication or something something...
logger.propagate = 0
# Logger object must be at minimum level
# logger.setLevel(int(np.min([level_file, level_stream]))) # BUG: this was causing issues!
logger.setLevel(logging.DEBUG)
# ---- Log to file
if tofile not in [None, False]:
format_date = '%Y/%m/%d %H:%M:%S'
format_file = "%(asctime)s %(levelname)8.8s [%(filename)20.20s:%(funcName)-20.20s]%(message)s"
file_formatter = logging.Formatter(format_file, format_date)
fhandler = logging.FileHandler(tofile, 'w')
fhandler.setFormatter(file_formatter)
fhandler.setLevel(level_file)
logger.addHandler(fhandler)
# Store output filename to `logger` object
logger.filename = tofile
# ---- Log To stdout
if tostr not in [None, False]:
format_date = '%H:%M:%S'
format_stream = "%(asctime)s %(levelname)s : %(message)s [%(filename)s:%(funcName)s]"
stream_formatter = logging.Formatter(format_stream, format_date)
handler = logging.StreamHandler(tostr)
handler.setFormatter(stream_formatter)
handler.setLevel(level_stream)
logger.addHandler(handler)
for lvl in ['DEBUG', 'INFO', 'WARNING', 'ERROR']:
setattr(logger, lvl, getattr(logging, lvl))
# Make sure that the `setLevel` command reaches the stream logger
logger.setLevel = lambda xx: logger.handlers[0].setLevel(xx)
return logger