diff --git a/synapse/util/logcontext.py b/synapse/util/logcontext.py
index d660ec785b..a58c723403 100644
--- a/synapse/util/logcontext.py
+++ b/synapse/util/logcontext.py
@@ -59,8 +59,8 @@ class LoggingContext(object):
__slots__ = [
"previous_context", "name", "ru_stime", "ru_utime",
- "db_txn_count", "db_txn_duration_ms", "db_sched_duration_ms",
- "usage_start", "usage_end",
+ "db_txn_count", "db_txn_duration_sec", "db_sched_duration_sec",
+ "usage_start",
"main_thread", "alive",
"request", "tag",
]
@@ -84,14 +84,15 @@ 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_ms):
+ def add_database_scheduled(self, sched_sec):
pass
def __nonzero__(self):
return False
+ __bool__ = __nonzero__ # python3
sentinel = Sentinel()
@@ -102,14 +103,16 @@ class LoggingContext(object):
self.ru_utime = 0.
self.db_txn_count = 0
- # ms spent waiting for db txns, excluding scheduling time
- self.db_txn_duration_ms = 0
+ # sec spent waiting for db txns, excluding scheduling time
+ self.db_txn_duration_sec = 0
- # ms spent waiting for db txns to be scheduled
- self.db_sched_duration_ms = 0
+ # sec spent waiting for db txns to be scheduled
+ self.db_sched_duration_sec = 0
+ # If alive has the thread resource usage when the logcontext last
+ # became active.
self.usage_start = None
- self.usage_end = None
+
self.main_thread = threading.current_thread()
self.request = None
self.tag = ""
@@ -158,12 +161,12 @@ class LoggingContext(object):
"""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",
@@ -184,47 +187,61 @@ class LoggingContext(object):
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 resource used since we started
if self.usage_start:
- self.usage_end = get_thread_resource_usage()
+ usage_end = get_thread_resource_usage()
+
+ self.ru_utime += usage_end.ru_utime - self.usage_start.ru_utime
+ self.ru_stime += usage_end.ru_stime - self.usage_start.ru_stime
+
+ self.usage_start = None
+ else:
+ logger.warning("Called stop on logcontext %s without calling start", self)
def get_resource_usage(self):
+ """Get CPU time used by this logcontext so far.
+
+ Returns:
+ tuple[float, float]: The user and system CPU usage in seconds
+ """
ru_utime = self.ru_utime
ru_stime = self.ru_stime
- if self.usage_start and threading.current_thread() is self.main_thread:
+ # 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
return ru_utime, ru_stime
- def add_database_transaction(self, duration_ms):
+ def add_database_transaction(self, duration_sec):
self.db_txn_count += 1
- self.db_txn_duration_ms += duration_ms
+ self.db_txn_duration_sec += duration_sec
- def add_database_scheduled(self, sched_ms):
+ def add_database_scheduled(self, sched_sec):
"""Record a use of the database pool
Args:
- sched_ms (int): number of milliseconds it took us to get a
+ sched_sec (float): number of seconds it took us to get a
connection
"""
- self.db_sched_duration_ms += sched_ms
+ self.db_sched_duration_sec += sched_sec
class LoggingContextFilter(logging.Filter):
@@ -278,7 +295,7 @@ 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,
)
@@ -301,31 +318,49 @@ def preserve_fn(f):
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 funtion completes.
+ deferred returned by the function completes.
Useful for wrapping functions that return a deferred which you don't yield
- on.
+ on (for instance because you want to pass it to deferred.gatherResults()).
+
+ 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.
"""
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(_set_context_cb, LoggingContext.sentinel)
+ 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 not isinstance(res, defer.Deferred):
+ return res
+
+ if res.called and not res.paused:
+ # The function should have maintained the logcontext, so we can
+ # optimise out the messing about
+ return res
+
+ # 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
@@ -340,11 +375,20 @@ 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.)
"""
- if isinstance(deferred, defer.Deferred) and not deferred.called:
- prev_context = LoggingContext.set_current_context(LoggingContext.sentinel)
- deferred.addBoth(_set_context_cb, prev_context)
+ 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
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