1 files changed, 10 insertions, 2 deletions
diff --git a/synapse/logging/opentracing.py b/synapse/logging/opentracing.py
index 10bd4a1461..b8081f197e 100644
--- a/synapse/logging/opentracing.py
+++ b/synapse/logging/opentracing.py
@@ -169,7 +169,7 @@ import inspect
 import logging
 import re
 from functools import wraps
-from typing import TYPE_CHECKING, Dict, Optional, Type
+from typing import TYPE_CHECKING, Dict, Optional, Pattern, Type
 
 import attr
 
@@ -259,10 +259,18 @@ except ImportError:
 logger = logging.getLogger(__name__)
 
 
+class SynapseTags:
+    # The message ID of any to_device message processed
+    TO_DEVICE_MESSAGE_ID = "to_device.message_id"
+
+    # Whether the sync response has new data to be returned to the client.
+    SYNC_RESULT = "sync.new_data"
+
+
 # Block everything by default
 # A regex which matches the server_names to expose traces for.
 # None means 'block everything'.
-_homeserver_whitelist = None
+_homeserver_whitelist = None  # type: Optional[Pattern[str]]
 
 # Util methods