From 39230d217104f3cd7aba9065dc478f935ce1e614 Mon Sep 17 00:00:00 2001 From: Richard van der Hoff <1389908+richvdh@users.noreply.github.com> Date: Tue, 24 Mar 2020 14:45:33 +0000 Subject: Clean up some LoggingContext stuff (#7120) * Pull Sentinel out of LoggingContext ... and drop a few unnecessary references to it * Factor out LoggingContext.current_context move `current_context` and `set_context` out to top-level functions. Mostly this means that I can more easily trace what's actually referring to LoggingContext, but I think it's generally neater. * move copy-to-parent into `stop` this really just makes `start` and `stop` more symetric. It also means that it behaves correctly if you manually `set_log_context` rather than using the context manager. * Replace `LoggingContext.alive` with `finished` Turn `alive` into `finished` and make it a bit better defined. --- synapse/logging/_structured.py | 4 +- synapse/logging/context.py | 234 +++++++++++++++++---------------- synapse/logging/scopecontextmanager.py | 13 +- 3 files changed, 125 insertions(+), 126 deletions(-) (limited to 'synapse/logging') diff --git a/synapse/logging/_structured.py b/synapse/logging/_structured.py index ffa7b20ca8..7372450b45 100644 --- a/synapse/logging/_structured.py +++ b/synapse/logging/_structured.py @@ -42,7 +42,7 @@ from synapse.logging._terse_json import ( TerseJSONToConsoleLogObserver, TerseJSONToTCPLogObserver, ) -from synapse.logging.context import LoggingContext +from synapse.logging.context import current_context def stdlib_log_level_to_twisted(level: str) -> LogLevel: @@ -86,7 +86,7 @@ class LogContextObserver(object): ].startswith("Timing out client"): return - context = LoggingContext.current_context() + context = current_context() # Copy the context information to the log event. if context is not None: diff --git a/synapse/logging/context.py b/synapse/logging/context.py index 860b99a4c6..a8eafb1c7c 100644 --- a/synapse/logging/context.py +++ b/synapse/logging/context.py @@ -175,7 +175,54 @@ class ContextResourceUsage(object): return res -LoggingContextOrSentinel = Union["LoggingContext", "LoggingContext.Sentinel"] +LoggingContextOrSentinel = Union["LoggingContext", "_Sentinel"] + + +class _Sentinel(object): + """Sentinel to represent the root context""" + + __slots__ = ["previous_context", "finished", "request", "scope", "tag"] + + def __init__(self) -> None: + # Minimal set for compatibility with LoggingContext + self.previous_context = None + self.finished = False + self.request = None + self.scope = None + self.tag = None + + def __str__(self): + return "sentinel" + + def copy_to(self, record): + pass + + def copy_to_twisted_log_entry(self, record): + record["request"] = None + record["scope"] = None + + def start(self): + pass + + def stop(self): + pass + + def add_database_transaction(self, duration_sec): + pass + + def add_database_scheduled(self, sched_sec): + pass + + def record_event_fetch(self, event_count): + pass + + def __nonzero__(self): + return False + + __bool__ = __nonzero__ # python3 + + +SENTINEL_CONTEXT = _Sentinel() class LoggingContext(object): @@ -199,76 +246,33 @@ class LoggingContext(object): "_resource_usage", "usage_start", "main_thread", - "alive", + "finished", "request", "tag", "scope", ] - thread_local = threading.local() - - class Sentinel(object): - """Sentinel to represent the root context""" - - __slots__ = ["previous_context", "alive", "request", "scope", "tag"] - - def __init__(self) -> None: - # Minimal set for compatibility with LoggingContext - self.previous_context = None - self.alive = None - self.request = None - self.scope = None - self.tag = None - - def __str__(self): - return "sentinel" - - def copy_to(self, record): - pass - - def copy_to_twisted_log_entry(self, record): - record["request"] = None - record["scope"] = None - - def start(self): - pass - - def stop(self): - pass - - def add_database_transaction(self, duration_sec): - pass - - def add_database_scheduled(self, sched_sec): - pass - - def record_event_fetch(self, event_count): - pass - - def __nonzero__(self): - return False - - __bool__ = __nonzero__ # python3 - - sentinel = Sentinel() - def __init__(self, name=None, parent_context=None, request=None) -> None: - self.previous_context = LoggingContext.current_context() + self.previous_context = current_context() self.name = name # track the resources used by this context so far self._resource_usage = ContextResourceUsage() - # If alive has the thread resource usage when the logcontext last - # became active. + # The thread resource usage when the logcontext became active. None + # if the context is not currently active. self.usage_start = None self.main_thread = get_thread_id() self.request = None self.tag = "" - self.alive = True self.scope = None # type: Optional[_LogContextScope] + # keep track of whether we have hit the __exit__ block for this context + # (suggesting that the the thing that created the context thinks it should + # be finished, and that re-activating it would suggest an error). + self.finished = False + self.parent_context = parent_context if self.parent_context is not None: @@ -283,44 +287,15 @@ class LoggingContext(object): return str(self.request) return "%s@%x" % (self.name, id(self)) - @classmethod - def current_context(cls) -> LoggingContextOrSentinel: - """Get the current logging context from thread local storage - - Returns: - LoggingContext: the current logging context - """ - return getattr(cls.thread_local, "current_context", cls.sentinel) - - @classmethod - def set_current_context( - cls, context: LoggingContextOrSentinel - ) -> LoggingContextOrSentinel: - """Set the current logging context in thread local storage - Args: - context(LoggingContext): The context to activate. - Returns: - The context that was previously active - """ - current = cls.current_context() - - if current is not context: - current.stop() - cls.thread_local.current_context = context - context.start() - return current - def __enter__(self) -> "LoggingContext": """Enters this logging context into thread local storage""" - old_context = self.set_current_context(self) + old_context = set_current_context(self) if self.previous_context != old_context: logger.warning( "Expected previous context %r, found %r", self.previous_context, old_context, ) - self.alive = True - return self def __exit__(self, type, value, traceback) -> None: @@ -329,24 +304,19 @@ class LoggingContext(object): Returns: None to avoid suppressing any exceptions that were thrown. """ - current = self.set_current_context(self.previous_context) + current = set_current_context(self.previous_context) if current is not self: - if current is self.sentinel: + if current is SENTINEL_CONTEXT: logger.warning("Expected logging context %s was lost", self) else: logger.warning( "Expected logging context %s but found %s", self, current ) - self.alive = False - - # if we have a parent, pass our CPU usage stats on - if self.parent_context is not None and hasattr( - self.parent_context, "_resource_usage" - ): - self.parent_context._resource_usage += self._resource_usage - # reset them in case we get entered again - self._resource_usage.reset() + # the fact that we are here suggests that the caller thinks that everything + # is done and dusted for this logcontext, and further activity will not get + # recorded against the correct metrics. + self.finished = True def copy_to(self, record) -> None: """Copy logging fields from this context to a log record or @@ -371,9 +341,14 @@ class LoggingContext(object): logger.warning("Started logcontext %s on different thread", self) return + if self.finished: + logger.warning("Re-starting finished log context %s", self) + # If we haven't already started record the thread resource usage so # far - if not self.usage_start: + if self.usage_start: + logger.warning("Re-starting already-active log context %s", self) + else: self.usage_start = get_thread_resource_usage() def stop(self) -> None: @@ -396,6 +371,15 @@ class LoggingContext(object): self.usage_start = None + # if we have a parent, pass our CPU usage stats on + if self.parent_context is not None and hasattr( + self.parent_context, "_resource_usage" + ): + self.parent_context._resource_usage += self._resource_usage + + # reset them in case we get entered again + self._resource_usage.reset() + def get_resource_usage(self) -> ContextResourceUsage: """Get resources used by this logcontext so far. @@ -409,7 +393,7 @@ class LoggingContext(object): # If we are on the correct thread and we're currently running then we # can include resource usage so far. is_main_thread = get_thread_id() == self.main_thread - if self.alive and self.usage_start and is_main_thread: + if self.usage_start and is_main_thread: utime_delta, stime_delta = self._get_cputime() res.ru_utime += utime_delta res.ru_stime += stime_delta @@ -492,7 +476,7 @@ class LoggingContextFilter(logging.Filter): Returns: True to include the record in the log output. """ - context = LoggingContext.current_context() + context = current_context() for key, value in self.defaults.items(): setattr(record, key, value) @@ -512,27 +496,24 @@ class PreserveLoggingContext(object): __slots__ = ["current_context", "new_context", "has_parent"] - def __init__(self, new_context: Optional[LoggingContextOrSentinel] = None) -> None: - if new_context is None: - self.new_context = LoggingContext.sentinel # type: LoggingContextOrSentinel - else: - self.new_context = new_context + def __init__( + self, new_context: LoggingContextOrSentinel = SENTINEL_CONTEXT + ) -> None: + self.new_context = new_context def __enter__(self) -> None: """Captures the current logging context""" - self.current_context = LoggingContext.set_current_context(self.new_context) + self.current_context = set_current_context(self.new_context) if self.current_context: self.has_parent = self.current_context.previous_context is not None - if not self.current_context.alive: - logger.debug("Entering dead context: %s", self.current_context) def __exit__(self, type, value, traceback) -> None: """Restores the current logging context""" - context = LoggingContext.set_current_context(self.current_context) + context = set_current_context(self.current_context) if context != self.new_context: - if context is LoggingContext.sentinel: + if not context: logger.warning("Expected logging context %s was lost", self.new_context) else: logger.warning( @@ -541,9 +522,30 @@ class PreserveLoggingContext(object): context, ) - if self.current_context is not LoggingContext.sentinel: - if not self.current_context.alive: - logger.debug("Restoring dead context: %s", self.current_context) + +_thread_local = threading.local() +_thread_local.current_context = SENTINEL_CONTEXT + + +def current_context() -> LoggingContextOrSentinel: + """Get the current logging context from thread local storage""" + return getattr(_thread_local, "current_context", SENTINEL_CONTEXT) + + +def set_current_context(context: LoggingContextOrSentinel) -> LoggingContextOrSentinel: + """Set the current logging context in thread local storage + Args: + context(LoggingContext): The context to activate. + Returns: + The context that was previously active + """ + current = current_context() + + if current is not context: + current.stop() + _thread_local.current_context = context + context.start() + return current def nested_logging_context( @@ -572,7 +574,7 @@ def nested_logging_context( if parent_context is not None: context = parent_context # type: LoggingContextOrSentinel else: - context = LoggingContext.current_context() + context = current_context() return LoggingContext( parent_context=context, request=str(context.request) + "-" + suffix ) @@ -604,7 +606,7 @@ def run_in_background(f, *args, **kwargs): CRITICAL error about an unhandled error will be logged without much indication about where it came from. """ - current = LoggingContext.current_context() + current = current_context() try: res = f(*args, **kwargs) except: # noqa: E722 @@ -625,7 +627,7 @@ def run_in_background(f, *args, **kwargs): # The function may have reset the context before returning, so # we need to restore it now. - ctx = LoggingContext.set_current_context(current) + ctx = set_current_context(current) # The original context will be restored when the deferred # completes, but there is nothing waiting for it, so it will @@ -674,7 +676,7 @@ def make_deferred_yieldable(deferred): # ok, we can't be sure that a yield won't block, so let's reset the # logcontext, and add a callback to the deferred to restore it. - prev_context = LoggingContext.set_current_context(LoggingContext.sentinel) + prev_context = set_current_context(SENTINEL_CONTEXT) deferred.addBoth(_set_context_cb, prev_context) return deferred @@ -684,7 +686,7 @@ ResultT = TypeVar("ResultT") def _set_context_cb(result: ResultT, context: LoggingContext) -> ResultT: """A callback function which just sets the logging context""" - LoggingContext.set_current_context(context) + set_current_context(context) return result @@ -752,7 +754,7 @@ def defer_to_threadpool(reactor, threadpool, f, *args, **kwargs): Deferred: A Deferred which fires a callback with the result of `f`, or an errback if `f` throws an exception. """ - logcontext = LoggingContext.current_context() + logcontext = current_context() def g(): with LoggingContext(parent_context=logcontext): diff --git a/synapse/logging/scopecontextmanager.py b/synapse/logging/scopecontextmanager.py index 4eed4f2338..dc3ab00cbb 100644 --- a/synapse/logging/scopecontextmanager.py +++ b/synapse/logging/scopecontextmanager.py @@ -19,7 +19,7 @@ from opentracing import Scope, ScopeManager import twisted -from synapse.logging.context import LoggingContext, nested_logging_context +from synapse.logging.context import current_context, nested_logging_context logger = logging.getLogger(__name__) @@ -49,11 +49,8 @@ class LogContextScopeManager(ScopeManager): (Scope) : the Scope that is active, or None if not available. """ - ctx = LoggingContext.current_context() - if ctx is LoggingContext.sentinel: - return None - else: - return ctx.scope + ctx = current_context() + return ctx.scope def activate(self, span, finish_on_close): """ @@ -70,9 +67,9 @@ class LogContextScopeManager(ScopeManager): """ enter_logcontext = False - ctx = LoggingContext.current_context() + ctx = current_context() - if ctx is LoggingContext.sentinel: + if not ctx: # We don't want this scope to affect. logger.error("Tried to activate scope outside of loggingcontext") return Scope(None, span) -- cgit 1.4.1