diff options
Diffstat (limited to 'synapse/util/logcontext.py')
| -rw-r--r-- | synapse/util/logcontext.py | 401 |
1 files changed, 272 insertions, 129 deletions
diff --git a/synapse/util/logcontext.py b/synapse/util/logcontext.py index 990216145e..8dcae50b39 100644 --- a/synapse/util/logcontext.py +++ b/synapse/util/logcontext.py @@ -22,10 +22,10 @@ them. See doc/log_contexts.rst for details on how this works. """ -from twisted.internet import defer - -import threading import logging +import threading + +from twisted.internet import defer logger = logging.getLogger(__name__) @@ -42,23 +42,128 @@ try: def get_thread_resource_usage(): return resource.getrusage(RUSAGE_THREAD) -except: +except Exception: # If the system doesn't support resource.getrusage(RUSAGE_THREAD) then we # won't track resource usage by returning None. def get_thread_resource_usage(): return None +class ContextResourceUsage(object): + """Object for tracking the resources used by a log context + + Attributes: + ru_utime (float): user CPU time (in seconds) + ru_stime (float): system CPU time (in seconds) + db_txn_count (int): number of database transactions done + db_sched_duration_sec (float): amount of time spent waiting for a + database connection + db_txn_duration_sec (float): amount of time spent doing database + transactions (excluding scheduling time) + evt_db_fetch_count (int): number of events requested from the database + """ + + __slots__ = [ + "ru_stime", "ru_utime", + "db_txn_count", "db_txn_duration_sec", "db_sched_duration_sec", + "evt_db_fetch_count", + ] + + def __init__(self, copy_from=None): + """Create a new ContextResourceUsage + + Args: + copy_from (ContextResourceUsage|None): if not None, an object to + copy stats from + """ + if copy_from is None: + self.reset() + else: + self.ru_utime = copy_from.ru_utime + self.ru_stime = copy_from.ru_stime + self.db_txn_count = copy_from.db_txn_count + + self.db_txn_duration_sec = copy_from.db_txn_duration_sec + self.db_sched_duration_sec = copy_from.db_sched_duration_sec + self.evt_db_fetch_count = copy_from.evt_db_fetch_count + + def copy(self): + return ContextResourceUsage(copy_from=self) + + def reset(self): + self.ru_stime = 0. + self.ru_utime = 0. + self.db_txn_count = 0 + + self.db_txn_duration_sec = 0 + self.db_sched_duration_sec = 0 + self.evt_db_fetch_count = 0 + + def __repr__(self): + return ("<ContextResourceUsage ru_stime='%r', ru_utime='%r', " + "db_txn_count='%r', db_txn_duration_sec='%r', " + "db_sched_duration_sec='%r', evt_db_fetch_count='%r'>") % ( + self.ru_stime, + self.ru_utime, + self.db_txn_count, + self.db_txn_duration_sec, + self.db_sched_duration_sec, + self.evt_db_fetch_count,) + + def __iadd__(self, other): + """Add another ContextResourceUsage's stats to this one's. + + Args: + other (ContextResourceUsage): the other resource usage object + """ + self.ru_utime += other.ru_utime + self.ru_stime += other.ru_stime + self.db_txn_count += other.db_txn_count + self.db_txn_duration_sec += other.db_txn_duration_sec + self.db_sched_duration_sec += other.db_sched_duration_sec + self.evt_db_fetch_count += other.evt_db_fetch_count + return self + + def __isub__(self, other): + self.ru_utime -= other.ru_utime + self.ru_stime -= other.ru_stime + self.db_txn_count -= other.db_txn_count + self.db_txn_duration_sec -= other.db_txn_duration_sec + self.db_sched_duration_sec -= other.db_sched_duration_sec + self.evt_db_fetch_count -= other.evt_db_fetch_count + return self + + def __add__(self, other): + res = ContextResourceUsage(copy_from=self) + res += other + return res + + def __sub__(self, other): + res = ContextResourceUsage(copy_from=self) + res -= other + return res + + class LoggingContext(object): """Additional context for log formatting. Contexts are scoped within a "with" block. + + If a parent is given when creating a new context, then: + - logging fields are copied from the parent to the new context on entry + - when the new context exits, the cpu usage stats are copied from the + child to the parent + Args: name (str): Name for the context for debugging. + parent_context (LoggingContext|None): The parent of the new context """ __slots__ = [ - "previous_context", "name", "usage_start", "usage_end", "main_thread", - "__dict__", "tag", "alive", + "previous_context", "name", "parent_context", + "_resource_usage", + "usage_start", + "main_thread", "alive", + "request", "tag", ] thread_local = threading.local() @@ -80,32 +185,49 @@ class LoggingContext(object): def stop(self): pass - def add_database_transaction(self, duration_ms): + 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): + def __init__(self, name=None, parent_context=None): self.previous_context = LoggingContext.current_context() self.name = name - self.ru_stime = 0. - self.ru_utime = 0. - self.db_txn_count = 0 - self.db_txn_duration = 0. + + # 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. self.usage_start = None + self.main_thread = threading.current_thread() + self.request = None self.tag = "" self.alive = True + self.parent_context = parent_context + def __str__(self): return "%s@%x" % (self.name, id(self)) @classmethod def current_context(cls): - """Get the current logging context from thread local storage""" + """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 @@ -133,18 +255,22 @@ class LoggingContext(object): self.previous_context, old_context ) self.alive = True + + if self.parent_context is not None: + self.parent_context.copy_to(self) + 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. + None to avoid suppressing any exceptions that were thrown. """ current = self.set_current_context(self.previous_context) if current is not self: if current is self.sentinel: - logger.debug("Expected logging context %s has been lost", self) + logger.warn("Expected logging context %s has been lost", self) else: logger.warn( "Current logging context %s is not expected context %s", @@ -154,47 +280,91 @@ class LoggingContext(object): self.previous_context = None self.alive = False + # if we have a parent, pass our CPU usage stats on + if self.parent_context is not None: + self.parent_context._resource_usage += self._resource_usage + + # reset them in case we get entered again + self._resource_usage.reset() + def copy_to(self, record): - """Copy fields from this context to the record""" - for key, value in self.__dict__.items(): - setattr(record, key, value) + """Copy logging fields from this context to a log record or + another LoggingContext + """ - record.ru_utime, record.ru_stime = self.get_resource_usage() + # 'request' is the only field we currently use in the logger, so that's + # all we need to copy + record.request = self.request def start(self): if threading.current_thread() is not self.main_thread: + logger.warning("Started logcontext %s on different thread", self) return - if self.usage_start and self.usage_end: - self.ru_utime += self.usage_end.ru_utime - self.usage_start.ru_utime - self.ru_stime += self.usage_end.ru_stime - self.usage_start.ru_stime - self.usage_start = None - self.usage_end = None - + # If we haven't already started record the thread resource usage so + # far if not self.usage_start: self.usage_start = get_thread_resource_usage() def stop(self): if threading.current_thread() is not self.main_thread: + logger.warning("Stopped logcontext %s on different thread", self) + return + + # When we stop, let's record the cpu used since we started + if not self.usage_start: + logger.warning( + "Called stop on logcontext %s without calling start", self, + ) return - if self.usage_start: - self.usage_end = get_thread_resource_usage() + usage_end = get_thread_resource_usage() + + self._resource_usage.ru_utime += usage_end.ru_utime - self.usage_start.ru_utime + self._resource_usage.ru_stime += usage_end.ru_stime - self.usage_start.ru_stime + + self.usage_start = None def get_resource_usage(self): - ru_utime = self.ru_utime - ru_stime = self.ru_stime + """Get resources used by this logcontext so far. - if self.usage_start and threading.current_thread() is self.main_thread: + Returns: + ContextResourceUsage: a *copy* of the object tracking resource + usage so far + """ + # we always return a copy, for consistency + res = self._resource_usage.copy() + + # If we are on the correct thread and we're currently running then we + # can include resource usage so far. + is_main_thread = threading.current_thread() is self.main_thread + if self.alive and self.usage_start and is_main_thread: current = get_thread_resource_usage() - ru_utime += current.ru_utime - self.usage_start.ru_utime - ru_stime += current.ru_stime - self.usage_start.ru_stime + res.ru_utime += current.ru_utime - self.usage_start.ru_utime + res.ru_stime += current.ru_stime - self.usage_start.ru_stime - return ru_utime, ru_stime + return res - def add_database_transaction(self, duration_ms): - self.db_txn_count += 1 - self.db_txn_duration += duration_ms / 1000. + def add_database_transaction(self, duration_sec): + self._resource_usage.db_txn_count += 1 + self._resource_usage.db_txn_duration_sec += duration_sec + + def add_database_scheduled(self, sched_sec): + """Record a use of the database pool + + Args: + sched_sec (float): number of seconds it took us to get a + connection + """ + self._resource_usage.db_sched_duration_sec += sched_sec + + def record_event_fetch(self, event_count): + """Record a number of events being fetched from the db + + Args: + event_count (int): number of events being fetched + """ + self._resource_usage.evt_db_fetch_count += event_count class LoggingContextFilter(logging.Filter): @@ -248,7 +418,7 @@ class PreserveLoggingContext(object): context = LoggingContext.set_current_context(self.current_context) if context != self.new_context: - logger.debug( + logger.warn( "Unexpected logging context: %s is not %s", context, self.new_context, ) @@ -261,105 +431,62 @@ class PreserveLoggingContext(object): ) -class _PreservingContextDeferred(defer.Deferred): - """A deferred that ensures that all callbacks and errbacks are called with - the given logging context. - """ - def __init__(self, context): - self._log_context = context - defer.Deferred.__init__(self) - - def addCallbacks(self, callback, errback=None, - callbackArgs=None, callbackKeywords=None, - errbackArgs=None, errbackKeywords=None): - callback = self._wrap_callback(callback) - errback = self._wrap_callback(errback) - return defer.Deferred.addCallbacks( - self, callback, - errback=errback, - callbackArgs=callbackArgs, - callbackKeywords=callbackKeywords, - errbackArgs=errbackArgs, - errbackKeywords=errbackKeywords, - ) +def preserve_fn(f): + """Function decorator which wraps the function with run_in_background""" + def g(*args, **kwargs): + return run_in_background(f, *args, **kwargs) + return g - def _wrap_callback(self, f): - def g(res, *args, **kwargs): - with PreserveLoggingContext(self._log_context): - res = f(res, *args, **kwargs) - return res - return g +def run_in_background(f, *args, **kwargs): + """Calls a function, ensuring that the current context is restored after + return from the function, and that the sentinel context is set once the + deferred returned by the function completes. -def preserve_context_over_fn(fn, *args, **kwargs): - """Takes a function and invokes it with the given arguments, but removes - and restores the current logging context while doing so. + Useful for wrapping functions that return a deferred which you don't yield + on (for instance because you want to pass it to deferred.gatherResults()). - If the result is a deferred, call preserve_context_over_deferred before - returning it. + Note that if you completely discard the result, you should make sure that + `f` doesn't raise any deferred exceptions, otherwise a scary-looking + CRITICAL error about an unhandled error will be logged without much + indication about where it came from. """ - with PreserveLoggingContext(): - res = fn(*args, **kwargs) + current = LoggingContext.current_context() + try: + res = f(*args, **kwargs) + except: # noqa: E722 + # the assumption here is that the caller doesn't want to be disturbed + # by synchronous exceptions, so let's turn them into Failures. + return defer.fail() - if isinstance(res, defer.Deferred): - return preserve_context_over_deferred(res) - else: + if not isinstance(res, defer.Deferred): return res - -def preserve_context_over_deferred(deferred, context=None): - """Given a deferred wrap it such that any callbacks added later to it will - be invoked with the current context. - - Deprecated: this almost certainly doesn't do want you want, ie make - the deferred follow the synapse logcontext rules: try - ``make_deferred_yieldable`` instead. - """ - if context is None: - context = LoggingContext.current_context() - d = _PreservingContextDeferred(context) - deferred.chainDeferred(d) - return d - - -def preserve_fn(f): - """Wraps a function, to ensure that the current context is restored after - return from the function, and that the sentinel context is set once the - deferred returned by the funtion completes. - - Useful for wrapping functions that return a deferred which you don't yield - on. - """ - def reset_context(result): - LoggingContext.set_current_context(LoggingContext.sentinel) - return result - - def g(*args, **kwargs): - current = LoggingContext.current_context() - res = f(*args, **kwargs) - if isinstance(res, defer.Deferred) and not res.called: - # The function will have reset the context before returning, so - # we need to restore it now. - LoggingContext.set_current_context(current) - - # The original context will be restored when the deferred - # completes, but there is nothing waiting for it, so it will - # get leaked into the reactor or some other function which - # wasn't expecting it. We therefore need to reset the context - # here. - # - # (If this feels asymmetric, consider it this way: we are - # effectively forking a new thread of execution. We are - # probably currently within a ``with LoggingContext()`` block, - # which is supposed to have a single entry and exit point. But - # by spawning off another deferred, we are effectively - # adding a new exit point.) - res.addBoth(reset_context) + if res.called and not res.paused: + # The function should have maintained the logcontext, so we can + # optimise out the messing about return res - return g + + # The function may have reset the context before returning, so + # we need to restore it now. + ctx = LoggingContext.set_current_context(current) + + # The original context will be restored when the deferred + # completes, but there is nothing waiting for it, so it will + # get leaked into the reactor or some other function which + # wasn't expecting it. We therefore need to reset the context + # here. + # + # (If this feels asymmetric, consider it this way: we are + # effectively forking a new thread of execution. We are + # probably currently within a ``with LoggingContext()`` block, + # which is supposed to have a single entry and exit point. But + # by spawning off another deferred, we are effectively + # adding a new exit point.) + res.addBoth(_set_context_cb, ctx) + return res -@defer.inlineCallbacks def make_deferred_yieldable(deferred): """Given a deferred, make it follow the Synapse logcontext rules: @@ -371,11 +498,27 @@ def make_deferred_yieldable(deferred): returning a deferred. Then, when the deferred completes, restores the current logcontext before running callbacks/errbacks. - (This is more-or-less the opposite operation to preserve_fn.) + (This is more-or-less the opposite operation to run_in_background.) """ - with PreserveLoggingContext(): - r = yield deferred - defer.returnValue(r) + if not isinstance(deferred, defer.Deferred): + return deferred + + if deferred.called and not deferred.paused: + # it looks like this deferred is ready to run any callbacks we give it + # immediately. We may as well optimise out the logcontext faffery. + return 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) + deferred.addBoth(_set_context_cb, prev_context) + return deferred + + +def _set_context_cb(result, context): + """A callback function which just sets the logging context""" + LoggingContext.set_current_context(context) + return result # modules to ignore in `logcontext_tracer` |