Fix rare notifier bug where listeners dont timeout

There was a race condition that caused the notifier to 'miss' the
timeout notification, since there were no other checks for the timeout
this caused listeners to get stuck in a loop until something happened.
This commit is contained in:
Erik Johnston 2016-12-09 15:43:18 +00:00
parent 1697f6a323
commit be14c24cea
2 changed files with 10 additions and 11 deletions

View File

@ -510,6 +510,7 @@ class SyncHandler(object):
Returns:
Deferred(SyncResult)
"""
logger.info("Calculating sync response for %r", sync_config.user)
# NB: The now_token gets changed by some of the generate_sync_* methods,
# this is due to some of the underlying streams not supporting the ability

View File

@ -294,14 +294,7 @@ class Notifier(object):
result = None
if timeout:
# Will be set to a _NotificationListener that we'll be waiting on.
# Allows us to cancel it.
listener = None
def timed_out():
if listener:
listener.deferred.cancel()
timer = self.clock.call_later(timeout / 1000., timed_out)
end_time = self.clock.time_msec() + timeout
prev_token = from_token
while not result:
@ -312,6 +305,10 @@ class Notifier(object):
if result:
break
now = self.clock.time_msec()
if end_time <= now:
break
# Now we wait for the _NotifierUserStream to be told there
# is a new token.
# We need to supply the token we supplied to callback so
@ -319,11 +316,12 @@ class Notifier(object):
prev_token = current_token
listener = user_stream.new_listener(prev_token)
with PreserveLoggingContext():
yield listener.deferred
yield self.clock.time_bound_deferred(
listener.deferred,
time_out=(end_time - now) / 1000.
)
except defer.CancelledError:
break
self.clock.cancel_call_later(timer, ignore_errs=True)
else:
current_token = user_stream.current_token
result = yield callback(from_token, current_token)