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
-
-
|
