Run the reactor with the sentinel logcontext

This fixes a class of 'Unexpected logcontext' messages, which were happening
because the logcontext was somewhat arbitrarily swapping between the sentinel
and the `run` logcontext.

1 files changed, 7 insertions, 2 deletions

diff --git a/synapse/app/homeserver.py b/synapse/app/homeserver.py
index 0b9d78c13c..2cdd2d39ff 100755
--- a/synapse/app/homeserver.py
+++ b/synapse/app/homeserver.py
@@ -52,7 +52,7 @@ from synapse.api.urls import (
 )
 from synapse.config.homeserver import HomeServerConfig
 from synapse.crypto import context_factory
-from synapse.util.logcontext import LoggingContext
+from synapse.util.logcontext import LoggingContext, PreserveLoggingContext
 from synapse.metrics import register_memory_metrics, get_metrics_for
 from synapse.metrics.resource import MetricsResource, METRICS_PREFIX
 from synapse.replication.resource import ReplicationResource, REPLICATION_PREFIX
@@ -456,7 +456,12 @@ def run(hs):
     def in_thread():
         # Uncomment to enable tracing of log context changes.
         # sys.settrace(logcontext_tracer)
-        with LoggingContext("run"):
+
+        # make sure that we run the reactor with the sentinel log context,
+        # otherwise other PreserveLoggingContext instances will get confused
+        # and complain when they see the logcontext arbitrarily swapping
+        # between the sentinel and `run` logcontexts.
+        with PreserveLoggingContext():
             change_resource_limit(hs.config.soft_file_limit)
             if hs.config.gc_thresholds:
                 gc.set_threshold(*hs.config.gc_thresholds)