borgbackup/borg/logger.py
2015-10-08 16:50:44 -04:00

91 lines
2.9 KiB
Python

"""logging facilities
The way to use this is as follows:
* each module declares its own logger, using:
from .logger import create_logger
logger = create_logger()
* then each module uses logger.info/warning/debug/etc according to the
level it believes is appropriate:
logger.debug('some intricate details you usually do not care about')
logger.info('verbose progress information')
logger.warning('some non-error condition that must always be reported')
logger.error('a fatal error')
... and so on. see the `logging documentation
<https://docs.python.org/3/howto/logging.html#when-to-use-logging>`_
for more information
* console interaction happens on stderr, that includes interactive
reporting functions like `help`, `info` and `list`
* ...except ``input()`` is special, because we can't control the
stream it is using, unfortunately. we assume that it won't clutter
stdout, because interaction would be broken then anyways
* advanced verbosity filters, based on what i described in
https://github.com/borgbackup/borg/pull/233#issuecomment-145100222
may eventually be implemented
"""
import inspect
import logging
import sys
def setup_logging(args, stream=None):
"""setup logging module according to the arguments provided
this sets up a stream handler logger on stderr (by default, if no
stream is provided) and verbosity levels.
"""
logging.raiseExceptions = False
l = logging.getLogger('')
sh = logging.StreamHandler(stream)
# other formatters will probably want this, but let's remove
# clutter on stderr
# example:
# sh.setFormatter(logging.Formatter('%(name)s: %(message)s'))
l.addHandler(sh)
levels = {None: logging.WARNING,
0: logging.WARNING,
1: logging.INFO,
2: logging.DEBUG}
# default to WARNING, -v goes to INFO and -vv to DEBUG
l.setLevel(levels[args.verbose])
return sh,
def find_parent_module():
"""find the name of a the first module calling this module
if we cannot find it, we return the current module's name
(__name__) instead.
"""
try:
frame = inspect.currentframe().f_back
module = inspect.getmodule(frame)
while module is None or module.__name__ == __name__:
frame = frame.f_back
module = inspect.getmodule(frame)
return module.__name__
except AttributeError:
# somehow we failed to find our module
# return the logger module name by default
return __name__
def create_logger(name=None):
"""create a Logger object with the proper path, which is returned by
find_parent_module() by default, or is provided via the commandline
this is really a shortcut for:
logger = logging.getLogger(__name__)
we use it to avoid errors and provide a more standard API.
"""
return logging.getLogger(name or find_parent_module())