#!/usr/bin/env python3
-
-"""Utilities related to logging."""
-
+# -*- coding: utf-8 -*-
+
+# © Copyright 2021-2022, Scott Gasch
+
+"""Utilities related to logging. To use it you must invoke
+:meth:`initialize_logging`. If you use the
+:meth:`bootstrap.initialize` decorator on your program's entry point,
+it will call this for you. See :meth:`python_modules.bootstrap.initialize`
+for more details. If you use this you get:
+
+* Ability to set logging level,
+* ability to define the logging format,
+* ability to tee all logging on stderr,
+* ability to tee all logging into a file,
+* ability to rotate said file as it grows,
+* ability to tee all logging into the system log (syslog) and
+ define the facility and level used to do so,
+* easy automatic pid/tid stamp on logging for debugging threads,
+* ability to squelch repeated log messages,
+* ability to log probabilistically in code,
+* ability to only see log messages from a particular module or
+ function,
+* ability to clear logging handlers added by earlier loaded modules.
+
+All of these are controlled via commandline arguments to your program,
+see the code below for details.
+"""
+
+import collections
import contextlib
import datetime
+import enum
+import io
import logging
-from logging.handlers import RotatingFileHandler, SysLogHandler
import os
-import pytz
+import random
import sys
+from logging.config import fileConfig
+from logging.handlers import RotatingFileHandler, SysLogHandler
+from typing import Any, Callable, Dict, Iterable, List, Optional
+
+import pytz
+from overrides import overrides
# This module is commonly used by others in here and should avoid
# taking any unnecessary dependencies back on them.
import argparse_utils
import config
-cfg = config.add_commandline_args(
- f'Logging ({__file__})',
- 'Args related to logging')
+cfg = config.add_commandline_args(f'Logging ({__file__})', 'Args related to logging')
cfg.add_argument(
'--logging_config_file',
type=argparse_utils.valid_filename,
default='INFO',
choices=['NOTSET', 'DEBUG', 'INFO', 'WARNING', 'ERROR', 'CRITICAL'],
metavar='LEVEL',
- help='The level below which to squelch log messages.',
+ help='The global default level below which to squelch log messages; see also --lmodule',
)
cfg.add_argument(
'--logging_format',
type=str,
- default='%(levelname)s:%(asctime)s: %(message)s',
- help='The format for lines logged via the logger module.'
+ default=None,
+ help='The format for lines logged via the logger module. See: https://docs.python.org/3/library/logging.html#formatter-objects',
)
cfg.add_argument(
'--logging_date_format',
type=str,
default='%Y/%m/%dT%H:%M:%S.%f%z',
metavar='DATEFMT',
- help='The format of any dates in --logging_format.'
+ help='The format of any dates in --logging_format.',
)
cfg.add_argument(
'--logging_console',
type=str,
default=None,
metavar='FILENAME',
- help='The filename of the logfile to write.'
+ help='The filename of the logfile to write.',
)
cfg.add_argument(
'--logging_filename_maxsize',
type=int,
- default=(1024*1024),
+ default=(1024 * 1024),
metavar='#BYTES',
- help='The maximum size (in bytes) to write to the logging_filename.'
+ help='The maximum size (in bytes) to write to the logging_filename.',
)
cfg.add_argument(
'--logging_filename_count',
type=int,
- default=2,
+ default=7,
metavar='COUNT',
- help='The number of logging_filename copies to keep before deleting.'
+ help='The number of logging_filename copies to keep before deleting.',
)
cfg.add_argument(
'--logging_syslog',
action=argparse_utils.ActionNoYes,
default=False,
- help='Should we log to localhost\'s syslog.'
+ help='Should we log to localhost\'s syslog.',
+)
+cfg.add_argument(
+ '--logging_syslog_facility',
+ type=str,
+ default='USER',
+ choices=[
+ 'NOTSET',
+ 'AUTH',
+ 'AUTH_PRIV',
+ 'CRON',
+ 'DAEMON',
+ 'FTP',
+ 'KERN',
+ 'LPR',
+ 'MAIL',
+ 'NEWS',
+ 'SYSLOG',
+ 'USER',
+ 'UUCP',
+ 'LOCAL0',
+ 'LOCAL1',
+ 'LOCAL2',
+ 'LOCAL3',
+ 'LOCAL4',
+ 'LOCAL5',
+ 'LOCAL6',
+ 'LOCAL7',
+ ],
+ metavar='SYSLOG_FACILITY_LIST',
+ help='The default syslog message facility identifier',
)
cfg.add_argument(
'--logging_debug_threads',
action=argparse_utils.ActionNoYes,
default=False,
- help='Should we prepend pid/tid data to all log messages?'
+ help='Should we prepend pid/tid data to all log messages?',
+)
+cfg.add_argument(
+ '--logging_debug_modules',
+ action=argparse_utils.ActionNoYes,
+ default=False,
+ help='Should we prepend module/function data to all log messages?',
)
cfg.add_argument(
'--logging_info_is_print',
action=argparse_utils.ActionNoYes,
default=False,
- help='logging.info also prints to stdout.'
+ help='logging.info also prints to stdout.',
)
+cfg.add_argument(
+ '--logging_squelch_repeats',
+ action=argparse_utils.ActionNoYes,
+ default=True,
+ help='Do we allow code to indicate that it wants to squelch repeated logging messages or should we always log?',
+)
+cfg.add_argument(
+ '--logging_probabilistically',
+ action=argparse_utils.ActionNoYes,
+ default=True,
+ help='Do we allow probabilistic logging (for code that wants it) or should we always log?',
+)
+# See also: OutputMultiplexer
+cfg.add_argument(
+ '--logging_captures_prints',
+ action=argparse_utils.ActionNoYes,
+ default=False,
+ help='When calling print, also log.info automatically.',
+)
+cfg.add_argument(
+ '--lmodule',
+ type=str,
+ metavar='<SCOPE>=<LEVEL>[,<SCOPE>=<LEVEL>...]',
+ help=(
+ 'Allows per-scope logging levels which override the global level set with --logging-level.'
+ + 'Pass a space separated list of <scope>=<level> where <scope> is one of: module, '
+ + 'module:function, or :function and <level> is a logging level (e.g. INFO, DEBUG...)'
+ ),
+)
+cfg.add_argument(
+ '--logging_clear_preexisting_handlers',
+ action=argparse_utils.ActionNoYes,
+ default=True,
+ help=(
+ 'Should logging code clear preexisting global logging handlers and thus insist that is '
+ + 'alone can add handlers. Use this to work around annoying modules that insert global '
+ + 'handlers with formats and logging levels you might now want. Caveat emptor, this may '
+ + 'cause you to miss logging messages.'
+ ),
+)
+
+BUILT_IN_PRINT = print
+LOGGING_INITIALIZED = False
+
+
+# A map from logging_callsite_id -> count of logged messages.
+squelched_logging_counts: Dict[str, int] = {}
+
+
+def squelch_repeated_log_messages(squelch_after_n_repeats: int) -> Callable:
+ """
+ A decorator that marks a function as interested in having the logging
+ messages that it produces be squelched (ignored) after it logs the
+ same message more than N times.
+
+ .. note::
+
+ This decorator affects *ALL* logging messages produced
+ within the decorated function. That said, messages must be
+ identical in order to be squelched. For example, if the same line
+ of code produces different messages (because of, e.g., a format
+ string), the messages are considered to be different.
+
+ """
+
+ def squelch_logging_wrapper(f: Callable):
+ import function_utils
+
+ identifier = function_utils.function_identifier(f)
+ squelched_logging_counts[identifier] = squelch_after_n_repeats
+ return f
+
+ return squelch_logging_wrapper
+
+
+class SquelchRepeatedMessagesFilter(logging.Filter):
+ """A filter that only logs messages from a given site with the same
+ (exact) message at the same logging level N times and ignores
+ subsequent attempts to log.
+
+ This filter only affects logging messages that repeat more than a
+ threshold number of times from functions that are tagged with the
+ @logging_utils.squelched_logging_ok decorator (see above); others
+ are ignored.
+
+ This functionality is enabled by default but can be disabled via
+ the :code:`--no_logging_squelch_repeats` commandline flag.
+ """
+
+ def __init__(self) -> None:
+ super().__init__()
+ self.counters: collections.Counter = collections.Counter()
+
+ @overrides
+ def filter(self, record: logging.LogRecord) -> bool:
+ id1 = f'{record.module}:{record.funcName}'
+ if id1 not in squelched_logging_counts:
+ return True
+ threshold = squelched_logging_counts[id1]
+ logsite = f'{record.pathname}+{record.lineno}+{record.levelno}+{record.msg}'
+ count = self.counters[logsite]
+ self.counters[logsite] += 1
+ return count < threshold
+
+
+class DynamicPerScopeLoggingLevelFilter(logging.Filter):
+ """This filter only allows logging messages from an allow list of
+ module names or module:function names. Blocks all others.
+ """
+
+ @staticmethod
+ def level_name_to_level(name: str) -> int:
+ numeric_level = getattr(logging, name, None)
+ if not isinstance(numeric_level, int):
+ raise ValueError(f'Invalid level: {name}')
+ return numeric_level
+
+ def __init__(
+ self,
+ default_logging_level: int,
+ per_scope_logging_levels: str,
+ ) -> None:
+ super().__init__()
+ self.valid_levels = set(['NOTSET', 'DEBUG', 'INFO', 'WARNING', 'ERROR', 'CRITICAL'])
+ self.default_logging_level = default_logging_level
+ self.level_by_scope = {}
+ if per_scope_logging_levels is not None:
+ for chunk in per_scope_logging_levels.split(','):
+ if '=' not in chunk:
+ print(
+ f'Malformed lmodule directive: "{chunk}", missing "=". Ignored.',
+ file=sys.stderr,
+ )
+ continue
+ try:
+ (scope, level) = chunk.split('=')
+ except ValueError:
+ print(
+ f'Malformed lmodule directive: "{chunk}". Ignored.',
+ file=sys.stderr,
+ )
+ continue
+ scope = scope.strip()
+ level = level.strip().upper()
+ if level not in self.valid_levels:
+ print(
+ f'Malformed lmodule directive: "{chunk}", bad level. Ignored.',
+ file=sys.stderr,
+ )
+ continue
+ self.level_by_scope[scope] = DynamicPerScopeLoggingLevelFilter.level_name_to_level(
+ level
+ )
+
+ @overrides
+ def filter(self, record: logging.LogRecord) -> bool:
+ """Decides whether or not to log based on an allow list."""
+
+ # First try to find a logging level by scope (--lmodule)
+ if len(self.level_by_scope) > 0:
+ min_level = None
+ for scope in (
+ record.module,
+ f'{record.module}:{record.funcName}',
+ f':{record.funcName}',
+ ):
+ level = self.level_by_scope.get(scope, None)
+ if level is not None:
+ if min_level is None or level < min_level:
+ min_level = level
+
+ # If we found one, use it instead of the global default level.
+ if min_level is not None:
+ return record.levelno >= min_level
+
+ # Otherwise, use the global logging level (--logging_level)
+ return record.levelno >= self.default_logging_level
+
+
+# A map from function_identifier -> probability of logging (0.0%..100.0%)
+probabilistic_logging_levels: Dict[str, float] = {}
+
+
+def logging_is_probabilistic(probability_of_logging: float) -> Callable:
+ """A decorator that indicates that all logging statements within the
+ scope of a particular (marked) function are not deterministic
+ (i.e. they do not always unconditionally log) but rather are
+ probabilistic (i.e. they log N% of the time, randomly).
+
+ .. note::
+ This affects *ALL* logging statements within the marked function.
+
+ That this functionality can be disabled (forcing all logged
+ messages to produce output) via the
+ :code:`--no_logging_probabilistically` cmdline argument.
+ """
+
+ def probabilistic_logging_wrapper(f: Callable):
+ import function_utils
+
+ identifier = function_utils.function_identifier(f)
+ probabilistic_logging_levels[identifier] = probability_of_logging
+ return f
+
+ return probabilistic_logging_wrapper
+
+
+class ProbabilisticFilter(logging.Filter):
+ """
+ A filter that logs messages probabilistically (i.e. randomly at some
+ percent chance).
+
+ This filter only affects logging messages from functions that have
+ been tagged with the @logging_utils.probabilistic_logging decorator.
+ """
+
+ @overrides
+ def filter(self, record: logging.LogRecord) -> bool:
+ id1 = f'{record.module}:{record.funcName}'
+ if id1 not in probabilistic_logging_levels:
+ return True
+ threshold = probabilistic_logging_levels[id1]
+ return (random.random() * 100.0) <= threshold
class OnlyInfoFilter(logging.Filter):
- def filter(self, record):
+ """A filter that only logs messages produced at the INFO logging
+ level. This is used by the ::code`--logging_info_is_print`
+ commandline option to select a subset of the logging stream to
+ send to a stdout handler.
+ """
+
+ @overrides
+ def filter(self, record: logging.LogRecord):
return record.levelno == logging.INFO
class MillisecondAwareFormatter(logging.Formatter):
- converter = datetime.datetime.fromtimestamp
+ """
+ A formatter for adding milliseconds to log messages which, for
+ whatever reason, the default python logger doesn't do.
+ """
+
+ converter = datetime.datetime.fromtimestamp # type: ignore
+ @overrides
def formatTime(self, record, datefmt=None):
- ct = self.converter(record.created, pytz.timezone("US/Pacific"))
+ ct = MillisecondAwareFormatter.converter(record.created, pytz.timezone("US/Pacific"))
if datefmt:
s = ct.strftime(datefmt)
else:
t = ct.strftime("%Y-%m-%d %H:%M:%S")
- s = "%s,%03d" % (t, record.msecs)
+ s = f"{t},{record.msecs:%03d}"
return s
+def log_about_logging(
+ logger,
+ default_logging_level,
+ preexisting_handlers_count,
+ fmt,
+ facility_name,
+):
+ """Some of the initial messages in the debug log are about how we
+ have set up logging itself."""
+
+ level_name = logging._levelToName.get(default_logging_level, str(default_logging_level))
+ logger.debug('Initialized global logging; default logging level is %s.', level_name)
+ if config.config['logging_clear_preexisting_handlers'] and preexisting_handlers_count > 0:
+ logger.debug(
+ 'Logging cleared %d global handlers (--logging_clear_preexisting_handlers)',
+ preexisting_handlers_count,
+ )
+ logger.debug('Logging format specification is "%s"', fmt)
+ if config.config['logging_debug_threads']:
+ logger.debug('...Logging format spec captures tid/pid. (--logging_debug_threads)')
+ if config.config['logging_debug_modules']:
+ logger.debug(
+ '...Logging format spec captures files/functions/lineno. (--logging_debug_modules)'
+ )
+ if config.config['logging_syslog']:
+ logger.debug(
+ 'Logging to syslog as %s with priority mapping based on level. (--logging_syslog)',
+ facility_name,
+ )
+ if config.config['logging_filename']:
+ logger.debug(
+ 'Logging to file "%s". (--logging_filename)', config.config["logging_filename"]
+ )
+ logger.debug(
+ '...with %d bytes max file size. (--logging_filename_maxsize)',
+ config.config["logging_filename_maxsize"],
+ )
+ logger.debug(
+ '...and %d rotating backup file count. (--logging_filename_count)',
+ config.config["logging_filename_count"],
+ )
+ if config.config['logging_console']:
+ logger.debug('Logging to the console (stderr). (--logging_console)')
+ if config.config['logging_info_is_print']:
+ logger.debug(
+ 'Logging logger.info messages will be repeated on stdout. (--logging_info_is_print)'
+ )
+ if config.config['logging_squelch_repeats']:
+ logger.debug(
+ 'Logging code allowed to request repeated messages be squelched. (--logging_squelch_repeats)'
+ )
+ else:
+ logger.debug(
+ 'Logging code forbidden to request messages be squelched; all messages logged. (--no_logging_squelch_repeats)'
+ )
+ if config.config['logging_probabilistically']:
+ logger.debug(
+ 'Logging code is allowed to request probabilistic logging. (--logging_probabilistically)'
+ )
+ else:
+ logger.debug(
+ 'Logging code is forbidden to request probabilistic logging; messages always logged. (--no_logging_probabilistically)'
+ )
+ if config.config['lmodule']:
+ logger.debug(
+ f'Logging dynamic per-module logging enabled. (--lmodule={config.config["lmodule"]})'
+ )
+ if config.config['logging_captures_prints']:
+ logger.debug(
+ 'Logging will capture printed data as logger.info messages. (--logging_captures_prints)'
+ )
+
+
def initialize_logging(logger=None) -> logging.Logger:
- assert config.has_been_parsed()
+ """Initialize logging for the program. This must be called if you want
+ to use any of the functionality provided by this module such as:
+
+ * Ability to set logging level,
+ * ability to define the logging format,
+ * ability to tee all logging on stderr,
+ * ability to tee all logging into a file,
+ * ability to rotate said file as it grows,
+ * ability to tee all logging into the system log (syslog) and
+ define the facility and level used to do so,
+ * easy automatic pid/tid stamp on logging for debugging threads,
+ * ability to squelch repeated log messages,
+ * ability to log probabilistically in code,
+ * ability to only see log messages from a particular module or
+ function,
+ * ability to clear logging handlers added by earlier loaded modules.
+
+ All of these are controlled via commandline arguments to your program,
+ see the code below for details.
+
+ If you use the
+ :meth:`bootstrap.initialize` decorator on your program's entry point,
+ it will call this for you. See :meth:`python_modules.bootstrap.initialize`
+ for more details.
+ """
+ global LOGGING_INITIALIZED
+ if LOGGING_INITIALIZED:
+ return logging.getLogger()
+ LOGGING_INITIALIZED = True
+
if logger is None:
- logger = logging.getLogger() # Root logger
+ logger = logging.getLogger()
+
+ # --logging_clear_preexisting_handlers removes logging handlers
+ # that were registered by global statements during imported module
+ # setup.
+ preexisting_handlers_count = 0
+ assert config.has_been_parsed()
+ if config.config['logging_clear_preexisting_handlers']:
+ while logger.hasHandlers():
+ logger.removeHandler(logger.handlers[0])
+ preexisting_handlers_count += 1
+ # --logging_config_file pulls logging settings from a config file
+ # skipping the rest of this setup.
if config.config['logging_config_file'] is not None:
- logging.config.fileConfig('logging.conf')
+ fileConfig(config.config['logging_config_file'])
return logger
- handlers = []
- numeric_level = getattr(
- logging,
- config.config['logging_level'].upper(),
- None
- )
- if not isinstance(numeric_level, int):
- raise ValueError('Invalid level: %s' % config.config['logging_level'])
+ handlers: List[logging.Handler] = []
+ handler: Optional[logging.Handler] = None
+
+ # Global default logging level (--logging_level); messages below
+ # this level will be silenced.
+ default_logging_level = getattr(logging, config.config['logging_level'].upper(), None)
+ if not isinstance(default_logging_level, int):
+ raise ValueError(f'Invalid level: {config.config["logging_level"]}')
- fmt = config.config['logging_format']
+ # Custom or default --logging_format?
+ if config.config['logging_format']:
+ fmt = config.config['logging_format']
+ else:
+ if config.config['logging_syslog']:
+ fmt = '%(levelname).1s:%(filename)s[%(process)d]: %(message)s'
+ else:
+ fmt = '%(levelname).1s:%(asctime)s: %(message)s'
+
+ # --logging_debug_threads and --logging_debug_modules both affect
+ # the format by prepending information about the pid/tid or
+ # file/function.
if config.config['logging_debug_threads']:
fmt = f'%(process)d.%(thread)d|{fmt}'
+ if config.config['logging_debug_modules']:
+ fmt = f'%(filename)s:%(funcName)s:%(lineno)s|{fmt}'
+ # --logging_syslog (optionally with --logging_syslog_facility)
+ # sets up for logging to use the standard system syslogd as a
+ # sink.
+ facility_name = None
if config.config['logging_syslog']:
- if sys.platform in ('win32', 'cygwin'):
- print(
- "WARNING: Current platform does not support syslog; IGNORING.",
- file=sys.stderr
- )
- else:
- handler = SysLogHandler()
-# for k, v in encoded_priorities.items():
-# handler.encodePriority(k, v)
+ if sys.platform not in ('win32', 'cygwin'):
+ if config.config['logging_syslog_facility']:
+ facility_name = 'LOG_' + config.config['logging_syslog_facility']
+ facility = SysLogHandler.__dict__.get(facility_name, SysLogHandler.LOG_USER) # type: ignore
+ assert facility is not None
+ handler = SysLogHandler(facility=facility, address='/dev/log')
handler.setFormatter(
MillisecondAwareFormatter(
fmt=fmt,
datefmt=config.config['logging_date_format'],
)
)
- handler.setLevel(numeric_level)
handlers.append(handler)
- if config.config['logging_filename'] is not None:
+ # --logging_filename (with friends --logging_filename_count and
+ # --logging_filename_maxsize) set up logging to a file on the
+ # filesystem with automatic rotation when it gets too big.
+ if config.config['logging_filename']:
handler = RotatingFileHandler(
config.config['logging_filename'],
- maxBytes = config.config['logging_filename_maxsize'],
- backupCount = config.config['logging_filename_count'],
+ maxBytes=config.config['logging_filename_maxsize'],
+ backupCount=config.config['logging_filename_count'],
)
- handler.setLevel(numeric_level)
handler.setFormatter(
MillisecondAwareFormatter(
fmt=fmt,
)
handlers.append(handler)
+ # --logging_console is, ahem, logging to the console.
if config.config['logging_console']:
handler = logging.StreamHandler(sys.stderr)
- handler.setLevel(numeric_level)
handler.setFormatter(
MillisecondAwareFormatter(
fmt=fmt,
if len(handlers) == 0:
handlers.append(logging.NullHandler())
-
for handler in handlers:
logger.addHandler(handler)
+
+ # --logging_info_is_print echoes any message to logger.info(x) as
+ # a print statement on stdout.
if config.config['logging_info_is_print']:
handler = logging.StreamHandler(sys.stdout)
handler.addFilter(OnlyInfoFilter())
logger.addHandler(handler)
- logger.setLevel(numeric_level)
+
+ # --logging_squelch_repeats allows code to request repeat logging
+ # messages (identical log site and message contents) to be
+ # silenced. Logging code must request this explicitly, it isn't
+ # automatic. This option just allows the silencing to happen.
+ if config.config['logging_squelch_repeats']:
+ for handler in handlers:
+ handler.addFilter(SquelchRepeatedMessagesFilter())
+
+ # --logging_probabilistically allows code to request
+ # non-deterministic logging where messages have some probability
+ # of being produced. Logging code must request this explicitly.
+ # This option just allows the non-deterministic behavior to
+ # happen. Disabling it will cause every log message to be
+ # produced.
+ if config.config['logging_probabilistically']:
+ for handler in handlers:
+ handler.addFilter(ProbabilisticFilter())
+
+ # --lmodule is a way to have a special logging level for just on
+ # module or one set of modules that is different than the one set
+ # globally via --logging_level.
+ for handler in handlers:
+ handler.addFilter(
+ DynamicPerScopeLoggingLevelFilter(
+ default_logging_level,
+ config.config['lmodule'],
+ )
+ )
+ logger.setLevel(0)
logger.propagate = False
+
+ # --logging_captures_prints, if set, will capture and log.info
+ # anything printed on stdout.
+ if config.config['logging_captures_prints']:
+ import builtins
+
+ def print_and_also_log(*arg, **kwarg):
+ f = kwarg.get('file', None)
+ if f == sys.stderr:
+ logger.warning(*arg)
+ else:
+ logger.info(*arg)
+ BUILT_IN_PRINT(*arg, **kwarg)
+
+ builtins.print = print_and_also_log
+
+ # At this point the logger is ready, handlers are set up,
+ # etc... so log about the logging configuration.
+ log_about_logging(
+ logger,
+ default_logging_level,
+ preexisting_handlers_count,
+ fmt,
+ facility_name,
+ )
return logger
def get_logger(name: str = ""):
+ """Get the global logger"""
logger = logging.getLogger(name)
return initialize_logging(logger)
def tprint(*args, **kwargs) -> None:
+ """Legacy function for printing a message augmented with thread id
+ still needed by some code. Please use --logging_debug_threads in
+ new code.
+ """
if config.config['logging_debug_threads']:
from thread_utils import current_thread_id
+
print(f'{current_thread_id()}', end="")
print(*args, **kwargs)
else:
def dprint(*args, **kwargs) -> None:
+ """Legacy function used to print to stderr still needed by some code.
+ Please just use normal logging with --logging_console which
+ accomplishes the same thing in new code.
+ """
print(*args, file=sys.stderr, **kwargs)
-class OutputSink(object):
-
- # Bits in the destination_bitv bitvector. Used to indicate the
- # output destination.
- STDOUT = 0x1
- STDERR = 0x2
- LOG_DEBUG = 0x4 # -\
- LOG_INFO = 0x8 # |
- LOG_WARNING = 0x10 # > Should provide logger to the c'tor.
- LOG_ERROR = 0x20 # |
- LOG_CRITICAL = 0x40 # _/
- FILENAME = 0x80 # Must provide a filename to the c'tor.
- HLOG = 0x100
-
- ALL_LOG_DESTINATIONS = (
- LOG_DEBUG | LOG_INFO | LOG_WARNING | LOG_ERROR | LOG_CRITICAL
- )
- ALL_OUTPUT_DESTINATIONS = 0x1FF
-
- def __init__(self,
- destination_bitv: int,
- *,
- logger=None,
- filename=None):
+class OutputMultiplexer(object):
+ """A class that broadcasts printed messages to several sinks
+ (including various logging levels, different files, different file
+ handles, the house log, etc...). See also
+ :class:`OutputMultiplexerContext` for an easy usage pattern.
+ """
+
+ class Destination(enum.IntEnum):
+ """Bits in the destination_bitv bitvector. Used to indicate the
+ output destination."""
+
+ # fmt: off
+ LOG_DEBUG = 0x01 # ⎫
+ LOG_INFO = 0x02 # ⎪
+ LOG_WARNING = 0x04 # ⎬ Must provide logger to the c'tor.
+ LOG_ERROR = 0x08 # ⎪
+ LOG_CRITICAL = 0x10 # ⎭
+ FILENAMES = 0x20 # Must provide a filename to the c'tor.
+ FILEHANDLES = 0x40 # Must provide a handle to the c'tor.
+ HLOG = 0x80
+ ALL_LOG_DESTINATIONS = (
+ LOG_DEBUG | LOG_INFO | LOG_WARNING | LOG_ERROR | LOG_CRITICAL
+ )
+ ALL_OUTPUT_DESTINATIONS = 0x8F
+ # fmt: on
+
+ def __init__(
+ self,
+ destination_bitv: int,
+ *,
+ logger=None,
+ filenames: Optional[Iterable[str]] = None,
+ handles: Optional[Iterable[io.TextIOWrapper]] = None,
+ ):
+ """
+ Constructs the OutputMultiplexer instance.
+
+ Args:
+ destination_bitv: a bitvector where each bit represents an
+ output destination. Multiple bits may be set.
+ logger: if LOG_* bits are set, you must pass a logger here.
+ filenames: if FILENAMES bit is set, this should be a list of
+ files you'd like to output into. This code handles opening
+ and closing said files.
+ handles: if FILEHANDLES bit is set, this should be a list of
+ already opened filehandles you'd like to output into. The
+ handles will remain open after the scope of the multiplexer.
+ """
if logger is None:
logger = logging.getLogger(None)
self.logger = logger
- if filename is not None:
- self.f = open(filename, "wb", buffering=0)
+ self.f: Optional[List[Any]] = None
+ if filenames is not None:
+ self.f = [open(filename, 'wb', buffering=0) for filename in filenames]
else:
- if self.destination_bitv & OutputSink.FILENAME:
- raise ValueError(
- "Filename argument is required if bitv & FILENAME"
- )
+ if destination_bitv & OutputMultiplexer.Destination.FILENAMES:
+ raise ValueError("Filenames argument is required if bitv & FILENAMES")
self.f = None
+
+ self.h: Optional[List[Any]] = None
+ if handles is not None:
+ self.h = list(handles)
+ else:
+ if destination_bitv & OutputMultiplexer.Destination.FILEHANDLES:
+ raise ValueError("Handle argument is required if bitv & FILEHANDLES")
+ self.h = None
+
self.set_destination_bitv(destination_bitv)
def get_destination_bitv(self):
+ """Where are we outputting?"""
return self.destination_bitv
def set_destination_bitv(self, destination_bitv: int):
- if destination_bitv & self.FILENAME and self.f is None:
- raise ValueError(
- "Filename argument is required if bitv & FILENAME"
- )
+ """Change the output destination_bitv to the one provided."""
+ if destination_bitv & self.Destination.FILENAMES and self.f is None:
+ raise ValueError("Filename argument is required if bitv & FILENAMES")
+ if destination_bitv & self.Destination.FILEHANDLES and self.h is None:
+ raise ValueError("Handle argument is required if bitv & FILEHANDLES")
self.destination_bitv = destination_bitv
def print(self, *args, **kwargs):
+ """Produce some output to all sinks."""
from string_utils import sprintf, strip_escape_sequences
+
end = kwargs.pop("end", None)
if end is not None:
if not isinstance(end, str):
sep = " "
if end is None:
end = "\n"
- if self.destination_bitv & self.STDOUT:
- print(buf, file=sys.stdout, sep=sep, end=end)
- if self.destination_bitv & self.STDERR:
- print(buf, file=sys.stderr, sep=sep, end=end)
if end == '\n':
buf += '\n'
- if self.destination_bitv & self.FILENAME and self.f is not None:
- self.f.write(buf.encode('utf-8'))
- self.f.flush()
+ if self.destination_bitv & self.Destination.FILENAMES and self.f is not None:
+ for _ in self.f:
+ _.write(buf.encode('utf-8'))
+ _.flush()
+
+ if self.destination_bitv & self.Destination.FILEHANDLES and self.h is not None:
+ for _ in self.h:
+ _.write(buf)
+ _.flush()
+
buf = strip_escape_sequences(buf)
if self.logger is not None:
- if self.destination_bitv & self.LOG_DEBUG:
+ if self.destination_bitv & self.Destination.LOG_DEBUG:
self.logger.debug(buf)
- if self.destination_bitv & self.LOG_INFO:
+ if self.destination_bitv & self.Destination.LOG_INFO:
self.logger.info(buf)
- if self.destination_bitv & self.LOG_WARNING:
+ if self.destination_bitv & self.Destination.LOG_WARNING:
self.logger.warning(buf)
- if self.destination_bitv & self.LOG_ERROR:
+ if self.destination_bitv & self.Destination.LOG_ERROR:
self.logger.error(buf)
- if self.destination_bitv & self.LOG_CRITICAL:
+ if self.destination_bitv & self.Destination.LOG_CRITICAL:
self.logger.critical(buf)
- if self.destination_bitv & self.HLOG:
+ if self.destination_bitv & self.Destination.HLOG:
hlog(buf)
def close(self):
+ """Close all open files."""
if self.f is not None:
- self.f.close()
-
-
-class OutputContext(OutputSink, contextlib.ContextDecorator):
- def __init__(self,
- destination_bitv: int,
- *,
- logger=None,
- filename=None):
- super().__init__(destination_bitv, logger=logger, filename=filename)
+ for _ in self.f:
+ _.close()
+
+
+class OutputMultiplexerContext(OutputMultiplexer, contextlib.ContextDecorator):
+ """
+ A context that uses an :class:`OutputMultiplexer`. e.g.::
+
+ with OutputMultiplexerContext(
+ OutputMultiplexer.LOG_INFO |
+ OutputMultiplexer.LOG_DEBUG |
+ OutputMultiplexer.FILENAMES |
+ OutputMultiplexer.FILEHANDLES,
+ filenames = [ '/tmp/foo.log', '/var/log/bar.log' ],
+ handles = [ f, g ]
+ ) as mplex:
+ mplex.print("This is a log message!")
+ """
+
+ def __init__(
+ self,
+ destination_bitv: OutputMultiplexer.Destination,
+ *,
+ logger=None,
+ filenames=None,
+ handles=None,
+ ):
+ super().__init__(
+ destination_bitv,
+ logger=logger,
+ filenames=filenames,
+ handles=handles,
+ )
def __enter__(self):
return self
- def __exit__(self, etype, value, traceback):
+ def __exit__(self, etype, value, traceback) -> bool:
super().close()
if etype is not None:
return False
def hlog(message: str) -> None:
+ """Write a message to the house log (syslog facility local7 priority
+ info) by calling /usr/bin/logger. This is pretty hacky but used
+ by a bunch of code. Another way to do this would be to use
+ :code:`--logging_syslog` and :code:`--logging_syslog_facility` but
+ I can't actually say that's easier.
+ """
message = message.replace("'", "'\"'\"'")
os.system(f"/usr/bin/logger -p local7.info -- '{message}'")
+
+
+if __name__ == '__main__':
+ import doctest
+
+ doctest.testmod()
projects / python_utils.git / blobdiff