class _LogManager(object):
"""
Twisted logger manager: tracks filtering predicates to support dynamic
per-namespace log level changes at runtime and supports adding/removing
observers at runtime.
"""
def __init__(self):
self._predicate = None
# Track dynamically added/removed observers:
# - keys: observers
# - values: FilteringLogObserver instances
self._observers = {}
def setup(self, level='warn', namespace_levels=None, text_file=sys.stderr,
time_format='%H:%M:%S.%f', handle_stdlib=True, stdlib_level='notset',
stdlib_prefix='stdlib.'):
"""
Initiates the twisted.logger system:
- level: default log level as a string (ie: 'warn', 'info', ....).
- namespace_levels: a dict of namespaces/log level names.
- text_file: where to write the log to.
- time_format: as supported by datetime.strftime.
- handle_stdlib: True/False.
- stdlib_level: level name, above which stdlib logging is handled.
- stdlib_prefix: added to stdlib logger name, used as namespace.
"""
file_observer = textFileLogObserver(text_file, timeFormat=time_format)
self._predicate = LogLevelFilterPredicate(
defaultLogLevel=LogLevel.levelWithName(level),
)
if namespace_levels:
for namespace, level_name in namespace_levels.items():
level = LogLevel.levelWithName(level_name)
self._predicate.setLogLevelForNamespace(namespace, level)
globalLogBeginner.beginLoggingTo([self._filtered_observer(file_observer)])
if handle_stdlib:
self._handle_stdlib(stdlib_level, stdlib_prefix)
def _filtered_observer(self, observer):
# Wraps `observer` in a t.l.FilteringLogObserver using the
# shared t.l.LogLevelFilterPredicate in `self._predicate`
return FilteringLogObserver(observer, [self._predicate])
@staticmethod
def _handle_stdlib(level_name, prefix):
"""
Directs standard library logging records to twisted.logger.
Standard library log recods will be handled at `level_name` or
above and logged to a namespace prefixed by `prefix`.
"""
stdlib_root_logger = logging.getLogger()
try:
level = getattr(logging, level_name.upper())
except AttributeError:
raise ValueError(level_name)
stdlib_root_logger.setLevel(level)
handler = _TwistedLoggerHandler(prefix)
stdlib_root_logger.addHandler(handler)
def set_level(self, namespace=None, level_name=None):
"""
Change the logging level of namespace to level.
If namespace is None, sets all namespaces to level_name.
If level_name is None, uses the default log level.
"""
if level_name:
level = LogLevel.levelWithName(level_name)
else:
level = self._predicate.defaultLogLevel
if namespace:
self._predicate.setLogLevelForNamespace(namespace, level)
else:
self._predicate.defaultLogLevel = level
self._predicate.clearLogLevels()
def add_observer(self, observer):
"""
Wraps `observer` in a FilteringLogObserver and adds it to the global
log publisher (filtering agrees with `setup` and `set_level` calls).
"""
filtered_observer = self._filtered_observer(observer)
globalLogPublisher.addObserver(filtered_observer)
self._observers[observer] = filtered_observer
def remove_observer(self, observer):
"""
Locates the FilteringLogObserver wrapping `observer` and removes it
from the global log publisher.
"""
filtered_observer = self._observers[observer]
globalLogPublisher.removeObserver(filtered_observer)
