# Licensed under a 3-clause BSD style license - see LICENSE.rst
"""This module defines a logging class based on the built-in logging module"""
from __future__ import print_function
import os
import sys
import logging
import warnings
from contextlib import contextmanager
from .config import ConfigurationItem
from . import config
from .utils.compat import inspect_getmodule
from .utils.console import color_print
from .utils.misc import find_current_module
__all__ = ['log', 'AstropyLogger', 'LoggingError']
[docs]class LoggingError(Exception):
"""
This exception is for various errors that occur in the astropy logger,
typically when activating or deactivating logger-related features.
"""
class _AstLogIPYExc(Exception):
"""
An exception that is used only as a placeholder to indicate to the
IPython exception-catching mechanism that the astropy
exception-capturing is activated. It should not actually be used as
an exception anywhere.
"""
# Read in configuration
LOG_LEVEL = ConfigurationItem('log_level', 'INFO',
"Threshold for the logging messages. Logging "
"messages that are less severe than this level "
"will be ignored. The levels are 'DEBUG', "
"'INFO', 'WARNING', 'ERROR'")
USE_COLOR = ConfigurationItem('use_color', True,
"Whether to use color for the level names")
LOG_WARNINGS = ConfigurationItem('log_warnings', True,
"Whether to log warnings.warn calls")
LOG_EXCEPTIONS = ConfigurationItem('log_exceptions', True,
"Whether to log exceptions before raising "
"them")
LOG_TO_FILE = ConfigurationItem('log_to_file', True,
"Whether to always log messages to a log "
"file")
LOG_FILE_PATH = ConfigurationItem('log_file_path', '',
"The file to log messages to. When '', "
"it defaults to a file 'astropy.log' in "
"the astropy config directory.")
LOG_FILE_LEVEL = ConfigurationItem('log_file_level', 'INFO',
"Threshold for logging messages to "
"log_file_path")
LOG_FILE_FORMAT = ConfigurationItem('log_file_format', "%(asctime)r, "
"%(origin)r, %(levelname)r, %(message)r",
"Format for log file entries")
# The following function is copied from the source code of Python 2.7 and 3.2.
# This function is not included in Python 2.6 and 3.1, so we have to include it
# here to provide uniform behavior across versions.
def _checkLevel(level):
'''
'''
if isinstance(level, int):
rv = level
elif str(level) == level:
if level not in logging._levelNames:
raise ValueError("Unknown level: %r" % level)
rv = logging._levelNames[level]
else:
raise TypeError("Level not an integer or a valid string: %r" % level)
return rv
# We now have to be sure that we overload the setLevel in FileHandler, again
# for compatibility with Python 2.6 and 3.1.
class FileHandler(logging.FileHandler):
def setLevel(self, level):
"""
Set the logging level of this handler.
"""
self.level = _checkLevel(level)
class FilterOrigin(object):
'''A filter for the record origin'''
def __init__(self, origin):
self.origin = origin
def filter(self, record):
return record.origin.startswith(self.origin)
class ListHandler(logging.Handler):
'''A handler that can be used to capture the records in a list'''
def __init__(self, filter_level=None, filter_origin=None):
logging.Handler.__init__(self)
self.log_list = []
def emit(self, record):
self.log_list.append(record)
def setLevel(self, level):
"""
Set the logging level of this handler.
"""
self.level = _checkLevel(level)
Logger = logging.getLoggerClass()
[docs]class AstropyLogger(Logger):
'''
This class is used to set up the Astropy logging.
The main functionality added by this class over the built-in
logging.Logger class is the ability to keep track of the origin of the
messages, the ability to enable logging of warnings.warn calls and
exceptions, and the addition of colorized output and context managers to
easily capture messages to a file or list.
'''
[docs] def makeRecord(self, name, level, pathname, lineno, msg, args, exc_info,
func=None, extra=None, sinfo=None):
if extra is None:
extra = {}
if 'origin' not in extra:
current_module = find_current_module(1, finddiff=[True, 'logging'])
if current_module is not None:
extra['origin'] = current_module.__name__
else:
extra['origin'] = 'unknown'
if sys.version_info[0] < 3 or \
(sys.version_info[0] == 3 and sys.version_info[1] < 2):
return Logger.makeRecord(self, name, level, pathname, lineno, msg,
args, exc_info, func=func, extra=extra)
else:
return Logger.makeRecord(self, name, level, pathname, lineno, msg,
args, exc_info, func=func, extra=extra,
sinfo=sinfo)
_showwarning_orig = None
def _showwarning(self, *args, **kwargs):
warning = args[0]
# Deliberately not using isinstance here: We want to display
# the class name only when it's not the default class,
# UserWarning. The name of subclasses of UserWarning should
# be displayed.
if type(warning) != UserWarning:
message = '{0}: {1}'.format(warning.__class__.__name__, args[0])
else:
message = unicode(args[0])
mod_path = args[2]
# Now that we have the module's path, we look through
# sys.modules to find the module object and thus the
# fully-package-specified module name. On Python 2, the
# module.__file__ is the compiled file name, not the .py, so
# we have to ignore the extension. On Python 3,
# module.__file__ is the original source file name, so things
# are more direct.
mod_name = None
if sys.version_info[0] < 3: # pragma: py2
for name, mod in sys.modules.items():
if getattr(mod, '__file__', '') == mod_path:
mod_name = mod.__name__
break
else: # pragma: py3
mod_path, ext = os.path.splitext(mod_path)
for name, mod in sys.modules.items():
path = os.path.splitext(getattr(mod, '__file__', ''))[0]
if path == mod_path:
mod_name = mod.__name__
break
if mod_name is not None:
self.warn(message, extra={'origin': mod_name})
else:
self.warn(message)
[docs] def warnings_logging_enabled(self):
return self._showwarning_orig is not None
[docs] def enable_warnings_logging(self):
'''
Enable logging of warnings.warn() calls
Once called, any subsequent calls to ``warnings.warn()`` are
redirected to this logger and emitted with level ``WARN``. Note that
this replaces the output from ``warnings.warn``.
This can be disabled with ``disable_warnings_logging``.
'''
if self.warnings_logging_enabled():
raise LoggingError("Warnings logging has already been enabled")
self._showwarning_orig = warnings.showwarning
warnings.showwarning = self._showwarning
[docs] def disable_warnings_logging(self):
'''
Disable logging of warnings.warn() calls
Once called, any subsequent calls to ``warnings.warn()`` are no longer
redirected to this logger.
This can be re-enabled with ``enable_warnings_logging``.
'''
if not self.warnings_logging_enabled():
raise LoggingError("Warnings logging has not been enabled")
if warnings.showwarning != self._showwarning:
raise LoggingError("Cannot disable warnings logging: "
"warnings.showwarning was not set by this "
"logger, or has been overridden")
warnings.showwarning = self._showwarning_orig
self._showwarning_orig = None
_excepthook_orig = None
def _excepthook(self, etype, value, traceback):
tb = traceback
while tb.tb_next is not None:
tb = tb.tb_next
mod = inspect_getmodule(tb)
# include the the error type in the message.
if len(value.args) > 0:
message = '{0}: {1}'.format(etype.__name__, str(value))
else:
message = unicode(etype.__name__)
if mod is not None:
self.error(message, extra={'origin': mod.__name__})
else:
self.error(message)
self._excepthook_orig(etype, value, traceback)
[docs] def exception_logging_enabled(self):
'''
Determine if the exception-logging mechanism is enabled.
Returns
-------
exclog : bool
True if exception logging is on, False if not.
'''
try:
ip = get_ipython()
except NameError:
ip = None
if ip is None:
return self._excepthook_orig is not None
else:
return _AstLogIPYExc in ip.custom_exceptions
[docs] def enable_exception_logging(self):
'''
Enable logging of exceptions
Once called, any uncaught exceptions will be emitted with level
``ERROR`` by this logger, before being raised.
This can be disabled with ``disable_exception_logging``.
'''
try:
ip = get_ipython()
except NameError:
ip = None
if self.exception_logging_enabled():
raise LoggingError("Exception logging has already been enabled")
if ip is None:
#standard python interpreter
self._excepthook_orig = sys.excepthook
sys.excepthook = self._excepthook
else:
#IPython has its own way of dealing with excepthook
#We need to locally define the function here, because IPython
#actually makes this a member function of their own class
def ipy_exc_handler(ipyshell, etype, evalue, tb, tb_offset=None):
# First use our excepthook
self._excepthook(etype, evalue, tb)
# Now also do IPython's traceback
ipyshell.showtraceback((etype, evalue, tb), tb_offset=tb_offset)
#now register the function with IPython
#note that we include _AstLogIPYExc so `disable_exception_logging`
#knows that it's disabling the right thing
ip.set_custom_exc((BaseException, _AstLogIPYExc), ipy_exc_handler)
#and set self._excepthook_orig to a no-op
self._excepthook_orig = lambda etype, evalue, tb: None
[docs] def disable_exception_logging(self):
'''
Disable logging of exceptions
Once called, any uncaught exceptions will no longer be emitted by this
logger.
This can be re-enabled with ``enable_exception_logging``.
'''
try:
ip = get_ipython()
except NameError:
ip = None
if not self.exception_logging_enabled():
raise LoggingError("Exception logging has not been enabled")
if ip is None:
#standard python interpreter
if sys.excepthook != self._excepthook:
raise LoggingError("Cannot disable exception logging: "
"sys.excepthook was not set by this logger, "
"or has been overridden")
sys.excepthook = self._excepthook_orig
self._excepthook_orig = None
else:
#IPython has its own way of dealing with exceptions
ip.set_custom_exc(tuple(), None)
[docs] def enable_color(self):
'''
Enable colorized output
'''
self._use_color = True
[docs] def disable_color(self):
'''
Disable colorized output
'''
self._use_color = False
def _stream_formatter(self, record):
'''
The formatter for standard output
'''
if record.levelno < logging.DEBUG or not self._use_color:
print(record.levelname, end='')
elif(record.levelno < logging.INFO):
color_print(record.levelname, 'magenta', end='')
elif(record.levelno < logging.WARN):
color_print(record.levelname, 'green', end='')
elif(record.levelno < logging.ERROR):
color_print(record.levelname, 'brown', end='')
else:
color_print(record.levelname, 'red', end='')
print(": " + record.msg + " [{0:s}]".format(record.origin))
@contextmanager
[docs] def log_to_file(self, filename, filter_level=None, filter_origin=None):
'''
Context manager to temporarily log messages to a file.
Parameters
----------
filename : str
The file to log messages to.
filter_level : str
If set, any log messages less important than ``filter_level`` will
not be output to the file. Note that this is in addition to the
top-level filtering for the logger, so if the logger has level
'INFO', then setting ``filter_level`` to ``INFO`` or ``DEBUG``
will have no effect, since these messages are already filtered
out.
filter_origin : str
If set, only log messages with an origin starting with
``filter_origin`` will be output to the file.
Notes
-----
By default, the logger already outputs log messages to a file set in
the Astropy configuration file. Using this context manager does not
stop log messages from being output to that file, nor does it stop log
messages from being printed to standard output.
Examples
--------
The context manager is used as::
with logger.log_to_file('myfile.log'):
# your code here
'''
fh = FileHandler(filename)
if filter_level is not None:
fh.setLevel(filter_level)
if filter_origin is not None:
fh.addFilter(FilterOrigin(filter_origin))
f = logging.Formatter(LOG_FILE_FORMAT())
fh.setFormatter(f)
self.addHandler(fh)
yield
self.removeHandler(fh)
@contextmanager
[docs] def log_to_list(self, filter_level=None, filter_origin=None):
'''
Context manager to temporarily log messages to a list.
Parameters
----------
filename : str
The file to log messages to.
filter_level : str
If set, any log messages less important than ``filter_level`` will
not be output to the file. Note that this is in addition to the
top-level filtering for the logger, so if the logger has level
'INFO', then setting ``filter_level`` to ``INFO`` or ``DEBUG``
will have no effect, since these messages are already filtered
out.
filter_origin : str
If set, only log messages with an origin starting with
``filter_origin`` will be output to the file.
Notes
-----
Using this context manager does not stop log messages from being
output to standard output.
Examples
--------
The context manager is used as::
with logger.log_to_list() as log_list:
# your code here
'''
lh = ListHandler()
if filter_level is not None:
lh.setLevel(filter_level)
if filter_origin is not None:
lh.addFilter(FilterOrigin(filter_origin))
self.addHandler(lh)
yield lh.log_list
self.removeHandler(lh)
[docs] def setLevel(self, level):
"""
Set the logging level of this logger.
"""
self.level = _checkLevel(level)
def _set_defaults(self):
'''
Reset logger to its initial state
'''
# Reset any previously installed hooks
if self.warnings_logging_enabled():
self.disable_warnings_logging()
if self.exception_logging_enabled():
self.disable_exception_logging()
# Remove all previous handlers
for handler in self.handlers[:]:
self.removeHandler(handler)
# Set levels
self.setLevel(LOG_LEVEL())
if USE_COLOR():
self.enable_color()
else:
self.disable_color()
# Set up the stdout handler
sh = logging.StreamHandler()
sh.emit = self._stream_formatter
self.addHandler(sh)
# Set up the main log file handler if requested (but this might fail if
# configuration directory or log file is not writeable).
if LOG_TO_FILE() and not os.environ.get('ASTROPY_TESTS_RUNNING'):
log_file_path = LOG_FILE_PATH()
# "None" as a string because it comes from config
try:
_ASTROPY_TEST_
testing_mode = True
except NameError:
testing_mode = False
if log_file_path == '' or testing_mode:
log_file_path = os.path.join(
config.get_config_dir(), "astropy.log")
else:
log_file_path = os.path.expanduser(log_file_path)
try:
fh = FileHandler(log_file_path)
except IOError:
warnings.warn(
"log file {0!r} could not be opened for writing".format(
log_file_path),
RuntimeWarning)
else:
formatter = logging.Formatter(LOG_FILE_FORMAT())
fh.setFormatter(formatter)
fh.setLevel(LOG_FILE_LEVEL())
self.addHandler(fh)
if LOG_WARNINGS():
self.enable_warnings_logging()
if LOG_EXCEPTIONS():
self.enable_exception_logging()
# Set up the class and initialize logger
_orig_logger_cls = logging.getLoggerClass()
logging.setLoggerClass(AstropyLogger)
try:
log = logging.getLogger('astropy')
log._set_defaults()
finally:
logging.setLoggerClass(_orig_logger_cls)
del _orig_logger_cls