diff options
Diffstat (limited to 'synapse/util')
| -rw-r--r-- | synapse/util/logcontext.py | 51 |
1 files changed, 37 insertions, 14 deletions
diff --git a/synapse/util/logcontext.py b/synapse/util/logcontext.py index 46a2855a15..13176b05ce 100644 --- a/synapse/util/logcontext.py +++ b/synapse/util/logcontext.py @@ -1,15 +1,23 @@ -from functools import wraps - import threading import logging + class LoggingContext(object): + """Additional context for log formatting. Contexts are scoped within a + "with" block. Contexts inherit the state of their parent contexts. + Args: + name (str): Name for the context for debugging. + """ + __slots__ = ["parent_context", "name", "__dict__"] thread_local = threading.local() class Sentinel(object): + """Sentinel to represent the root context""" + __slots__ = [] + def copy_to(self, record): pass @@ -20,13 +28,15 @@ class LoggingContext(object): self.name = name def __str__(self): - return "%s@%x" % (self.name, id(self)) + return "%s@%x" % (self.name, id(self)) @classmethod def current_context(cls): + """Get the current logging context from thread local storage""" return getattr(cls.thread_local, "current_context", cls.sentinel) def __enter__(self): + """Enters this logging context into thread local storage""" if self.parent_context is not None: raise Exception("Attempt to enter logging context multiple times") self.parent_context = self.current_context() @@ -34,6 +44,11 @@ class LoggingContext(object): return self def __exit__(self, type, value, traceback): + """Restore the logging context in thread local storage to the state it + was before this context was entered. + Returns: + None to avoid suppressing any exeptions that were thrown. + """ if self.thread_local.current_context is not self: logging.error( "Current logging context %s is not the expected context %s", @@ -44,29 +59,32 @@ class LoggingContext(object): self.parent_context = None def __getattr__(self, name): + """Delegate member lookup to parent context""" return getattr(self.parent_context, name) def copy_to(self, record): + """Copy fields from this context and its parents to the record""" if self.parent_context is not None: self.parent_context.copy_to(record) for key, value in self.__dict__.items(): setattr(record, key, value) - @classmethod - def wrap_callback(cls, callback): - context = cls.current_context() - @wraps(callback) - def wrapped(*args, **kargs): - cls.thread_local.current_context = context - return callback(*args, **kargs) - return wrapped - class LoggingContextFilter(logging.Filter): + """Logging filter that adds values from the current logging context to each + record. + Args: + **defaults: Default values to avoid formatters complaining about + missing fields + """ def __init__(self, **defaults): self.defaults = defaults def filter(self, record): + """Add each fields from the logging contexts to the record. + Returns: + True to include the record in the log output. + """ context = LoggingContext.current_context() for key, value in self.defaults.items(): setattr(record, key, value) @@ -75,11 +93,16 @@ class LoggingContextFilter(logging.Filter): class PreserveLoggingContext(object): + """Captures the current logging context and restores it when the scope is + exited. Used to restore the context after a function using + @defer.inlineCallbacks is resumed by a callback from the reactor.""" + __slots__ = ["current_context"] + def __enter__(self): + """Captures the current logging context""" self.current_context = LoggingContext.current_context() def __exit__(self, type, value, traceback): + """Restores the current logging context""" LoggingContext.thread_local.current_context = self.current_context - - |