Use DeferredLock instead of threading.Lock

Signed-off-by: Olivier Wilkinson (reivilibre) <olivier@librepush.net>

synapse/handlers/stats.py

@@ -66,12 +66,13 @@ class StatsHandler(StateDeltasHandler):
 
         @defer.inlineCallbacks
         def process():
+            yield lock.acquire()
             try:
                 yield self._unsafe_process()
             finally:
-                lock.release()
+                yield lock.release()
 
-        if lock.acquire(blocking=False):
+        if not lock.locked:
             # we only want to run this process one-at-a-time,
             # and also, if the initial background updater wants us to keep out,
             # we should respect that.

synapse/storage/stats.py

@@ -16,7 +16,8 @@
 
 import logging
 from itertools import chain
-from threading import Lock
+
+from twisted.internet.defer import DeferredLock
 
 from synapse.storage.state_deltas import StateDeltasStore
 from synapse.util.caches.descriptors import cached
@@ -57,7 +58,7 @@ class StatsStore(StateDeltasStore):
         self.stats_enabled = hs.config.stats_enabled
         self.stats_bucket_size = hs.config.stats_bucket_size
 
-        self.stats_delta_processing_lock = Lock()
+        self.stats_delta_processing_lock = DeferredLock()
 
         self.register_noop_background_update("populate_stats_createtables")
         self.register_noop_background_update("populate_stats_process_rooms")