Source code for astropy.logger

# Licensed under a 3-clause BSD style license - see LICENSE.rst
"""This module defines a logging class based on the built-in logging module.

.. note::

    This module is meant for internal ``astropy`` usage. For use in other
    packages, we recommend implementing your own logger instead.

"""

import inspect
import os
import sys
import logging
import warnings
from contextlib import contextmanager

from . import config as _config
from . import conf as _conf
from .utils import find_current_module
from .utils.exceptions import AstropyWarning, AstropyUserWarning

__all__ = ['Conf', 'conf', 'log', 'AstropyLogger', 'LoggingError']

# import the logging levels from logging so that one can do:
# log.setLevel(log.DEBUG), for example
logging_levels = ['NOTSET', 'DEBUG', 'INFO', 'WARNING', 'ERROR', 'CRITICAL',
                  'FATAL', ]
for level in logging_levels:
    globals()[level] = getattr(logging, level)
__all__ += logging_levels


# Initialize by calling _init_log()
log = None


[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. """
[docs]class Conf(_config.ConfigNamespace): """ Configuration parameters for `astropy.logger`. """ log_level = _config.ConfigItem( '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'``.") log_warnings = _config.ConfigItem( True, "Whether to log `warnings.warn` calls.") log_exceptions = _config.ConfigItem( False, "Whether to log exceptions before raising " "them.") log_to_file = _config.ConfigItem( False, "Whether to always log messages to a log " "file.") log_file_path = _config.ConfigItem( '', "The file to log messages to. If empty string is given, " "it defaults to a file ``'astropy.log'`` in " "the astropy config directory.") log_file_level = _config.ConfigItem( 'INFO', "Threshold for logging messages to " "`log_file_path`.") log_file_format = _config.ConfigItem( "%(asctime)r, " "%(origin)r, %(levelname)r, %(message)r", "Format for log file entries.") log_file_encoding = _config.ConfigItem( '', "The encoding (e.g., UTF-8) to use for the log file. If empty string " "is given, it defaults to the platform-preferred encoding.")
conf = Conf() def _init_log(): """Initializes the Astropy log--in most circumstances this is called automatically when importing astropy. """ global log orig_logger_cls = logging.getLoggerClass() logging.setLoggerClass(AstropyLogger) try: log = logging.getLogger('astropy') log._set_defaults() finally: logging.setLoggerClass(orig_logger_cls) return log def _teardown_log(): """Shut down exception and warning logging (if enabled) and clear all Astropy loggers from the logging module's cache. This involves poking some logging module internals, so much if it is 'at your own risk' and is allowed to pass silently if any exceptions occur. """ global log if log.exception_logging_enabled(): log.disable_exception_logging() if log.warnings_logging_enabled(): log.disable_warnings_logging() del log # Now for the fun stuff... try: logging._acquireLock() try: loggerDict = logging.Logger.manager.loggerDict for key in loggerDict.keys(): if key == 'astropy' or key.startswith('astropy.'): del loggerDict[key] finally: logging._releaseLock() except Exception: pass 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' 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): # Bail out if we are not catching a warning from Astropy if not isinstance(args[0], AstropyWarning): return self._showwarning_orig(*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, # AstropyWarning. The name of subclasses of AstropyWarning should # be displayed. if type(warning) not in (AstropyWarning, AstropyUserWarning): message = f'{warning.__class__.__name__}: {args[0]}' else: message = str(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. The module.__file__ is the original source file name. mod_name = None mod_path, ext = os.path.splitext(mod_path) for name, mod in list(sys.modules.items()): try: # Believe it or not this can fail in some cases: # https://github.com/astropy/astropy/issues/2671 path = os.path.splitext(getattr(mod, '__file__', ''))[0] except Exception: continue if path == mod_path: mod_name = mod.__name__ break if mod_name is not None: self.warning(message, extra={'origin': mod_name}) else: self.warning(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): if traceback is None: mod = None else: 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 = f'{etype.__name__}: {str(value)}' else: message = str(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 ''' _conf.use_color = True
[docs] def disable_color(self): ''' Disable colorized output ''' _conf.use_color = False
[docs] @contextmanager 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 ''' encoding = conf.log_file_encoding if conf.log_file_encoding else None fh = logging.FileHandler(filename, encoding=encoding) if filter_level is not None: fh.setLevel(filter_level) if filter_origin is not None: fh.addFilter(FilterOrigin(filter_origin)) f = logging.Formatter(conf.log_file_format) fh.setFormatter(f) self.addHandler(fh) yield fh.close() self.removeHandler(fh)
[docs] @contextmanager 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)
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(conf.log_level) # Set up the stdout handler sh = StreamHandler() 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 conf.log_to_file: log_file_path = conf.log_file_path # "None" as a string because it comes from config try: _ASTROPY_TEST_ testing_mode = True except NameError: testing_mode = False try: if log_file_path == '' or testing_mode: log_file_path = os.path.join( _config.get_config_dir('astropy'), "astropy.log") else: log_file_path = os.path.expanduser(log_file_path) encoding = conf.log_file_encoding if conf.log_file_encoding else None fh = logging.FileHandler(log_file_path, encoding=encoding) except OSError as e: warnings.warn( f'log file {log_file_path!r} could not be opened for writing: {str(e)}', RuntimeWarning) else: formatter = logging.Formatter(conf.log_file_format) fh.setFormatter(formatter) fh.setLevel(conf.log_file_level) self.addHandler(fh) if conf.log_warnings: self.enable_warnings_logging() if conf.log_exceptions: self.enable_exception_logging()
class StreamHandler(logging.StreamHandler): """ A specialized StreamHandler that logs INFO and DEBUG messages to stdout, and all other messages to stderr. Also provides coloring of the output, if enabled in the parent logger. """ def emit(self, record): ''' The formatter for stderr ''' if record.levelno <= logging.INFO: stream = sys.stdout else: stream = sys.stderr if record.levelno < logging.DEBUG or not _conf.use_color: print(record.levelname, end='', file=stream) else: # Import utils.console only if necessary and at the latest because # the import takes a significant time [#4649] from .utils.console import color_print if record.levelno < logging.INFO: color_print(record.levelname, 'magenta', end='', file=stream) elif record.levelno < logging.WARN: color_print(record.levelname, 'green', end='', file=stream) elif record.levelno < logging.ERROR: color_print(record.levelname, 'brown', end='', file=stream) else: color_print(record.levelname, 'red', end='', file=stream) record.message = f"{record.msg} [{record.origin:s}]" print(": " + record.message, file=stream) class FilterOrigin: '''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)