#!/usr/bin/env python3
# -*- coding: utf-8 -*-
-"""Utilities related to logging."""
+# © 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
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.
+ .. 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.
"""
class SquelchRepeatedMessagesFilter(logging.Filter):
- """
- A filter that only logs messages from a given site with the same
+ """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; others are
- ignored.
+ 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 --no_logging_squelch_repeats commandline flag.
-
+ the :code:`--no_logging_squelch_repeats` commandline flag.
"""
def __init__(self) -> None:
class DynamicPerScopeLoggingLevelFilter(logging.Filter):
"""This filter only allows logging messages from an allow list of
- module names or module:function names. Blocks others.
-
+ module names or module:function names. Blocks all others.
"""
@staticmethod
@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
def logging_is_probabilistic(probability_of_logging: float) -> Callable:
- """
- A decorator that indicates that all logging statements within the
+ """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).
+ probabilistic (i.e. they log N% of the time, randomly).
- Note that this functionality can be disabled (forcing all logged
- messages to produce output) via the --no_logging_probabilistically
- cmdline argument.
-
- This affects *ALL* logging statements within the marked function.
+ .. 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):
This filter only affects logging messages from functions that have
been tagged with the @logging_utils.probabilistic_logging decorator.
-
"""
@overrides
class OnlyInfoFilter(logging.Filter):
- """
- A filter that only logs messages produced at the INFO logging
- level. This is used by the logging_info_is_print commandline
- option to select a subset of the logging stream to send to a
- stdout handler.
-
+ """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
"""
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
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(f'Initialized global logging; default logging level is {level_name}.')
+ logger.debug('Initialized global logging; default logging level is %s.', level_name)
if config.config['logging_clear_preexisting_handlers'] and preexisting_handlers_count > 0:
- msg = f'Logging cleared {preexisting_handlers_count} global handlers (--logging_clear_preexisting_handlers)'
- logger.warning(msg)
- logger.debug(f'Logging format specification is "{fmt}"')
+ 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)')
+ 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)'
+ '...Logging format spec captures files/functions/lineno. (--logging_debug_modules)'
)
if config.config['logging_syslog']:
- logger.debug(f'Logging to syslog as {facility_name} with priority mapping based on level')
+ logger.debug(
+ 'Logging to syslog as %s with priority mapping based on level. (--logging_syslog)',
+ facility_name,
+ )
if config.config['logging_filename']:
- logger.debug(f'Logging to filename {config.config["logging_filename"]}')
- logger.debug(f'...with {config.config["logging_filename_maxsize"]} bytes max file size.')
logger.debug(
- f'...and {config.config["logging_filename_count"]} rotating backup file count.'
+ '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).')
+ 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)'
+ '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)'
+ '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)'
+ '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)'
+ '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)'
+ '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"]})'
+ 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)'
+ 'Logging will capture printed data as logger.info messages. (--logging_captures_prints)'
)
def initialize_logging(logger=None) -> logging.Logger:
+ """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()
if logger is None:
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']:
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:
fileConfig(config.config['logging_config_file'])
return logger
handlers: List[logging.Handler] = []
handler: Optional[logging.Handler] = None
- # Global default logging level (--logging_level)
+ # 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"]}')
+ # Custom or default --logging_format?
if config.config['logging_format']:
fmt = config.config['logging_format']
else:
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 not in ('win32', 'cygwin'):
)
handlers.append(handler)
+ # --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'],
)
handlers.append(handler)
+ # --logging_console is, ahem, logging to the console.
if config.config['logging_console']:
handler = logging.StreamHandler(sys.stderr)
handler.setFormatter(
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)
+ # --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(
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 get_logger(name: str = ""):
+ """Get the global logger"""
logger = logging.getLogger(name)
return initialize_logging(logger)
"""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
"""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 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 OutputMultiplexerContext for an
- easy usage pattern.
-
+ """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):
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
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):
+ """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:
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)
hlog(buf)
def close(self):
+ """Close all open files."""
if self.f is not None:
for _ in self.f:
_.close()
class OutputMultiplexerContext(OutputMultiplexer, contextlib.ContextDecorator):
"""
- A context that uses an OutputMultiplexer. e.g.
+ A context that uses an :class:`OutputMultiplexer`. e.g.::
with OutputMultiplexerContext(
OutputMultiplexer.LOG_INFO |
handles = [ f, g ]
) as mplex:
mplex.print("This is a log message!")
-
"""
def __init__(
"""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
- --logging_syslog and --logging_syslog_facility but I can't
- actually say that's easier.
-
+ :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}'")
projects / python_utils.git / blobdiff