Fix bug when running presence off master

changelog.d/10149.bugfix

@@ -0,0 +1 @@
+Fix bug where presence updates would stop working when using a presence writer worker.

synapse/storage/databases/main/presence.py

@@ -50,7 +50,7 @@ def __init__(
                 instance_name=self._instance_name,
                 tables=[("presence_stream", "instance_name", "stream_id")],
                 sequence_name="presence_stream_sequence",
-                writers=hs.config.worker.writers.to_device,
+                writers=hs.config.worker.writers.presence,
             )
         else:
             self._presence_id_gen = StreamIdGenerator(

synapse/storage/util/id_generators.py

@@ -397,6 +397,10 @@ def get_next(self):
                 # ... persist event ...
         """
 
+        # If we have a list of instance that are allowed to write to this
+        # stream, make sure we're in it.
+        assert not self._writers or self._instance_name in self._writers
+
         return _MultiWriterCtxManager(self)
 
     def get_next_mult(self, n: int):
@@ -406,6 +410,10 @@ def get_next_mult(self, n: int):
                 # ... persist events ...
         """
 
+        # If we have a list of instance that are allowed to write to this
+        # stream, make sure we're in it.
+        assert not self._writers or self._instance_name in self._writers
+
         return _MultiWriterCtxManager(self, n)
 
     def get_next_txn(self, txn: LoggingTransaction):
@@ -416,6 +424,10 @@ def get_next_txn(self, txn: LoggingTransaction):
             # ... persist event ...
         """
 
+        # If we have a list of instance that are allowed to write to this
+        # stream, make sure we're in it.
+        assert not self._writers or self._instance_name in self._writers
+
         next_id = self._load_next_id_txn(txn)
 
         with self._lock: