Enable passing typing stream writers as a list. (#11237)

This makes the typing stream writer config match the other stream writers
that only currently support a single worker.

8 files changed, 24 insertions, 16 deletions

diff --git a/changelog.d/11237.misc b/changelog.d/11237.misc
new file mode 100644
index 0000000000..b90efc6535
--- /dev/null
+++ b/changelog.d/11237.misc
@@ -0,0 +1 @@
+Allow `stream_writers.typing` config to be a list of one worker.
diff --git a/synapse/config/workers.py b/synapse/config/workers.py
index 462630201d..4507992031 100644
--- a/synapse/config/workers.py
+++ b/synapse/config/workers.py
@@ -63,7 +63,8 @@ class WriterLocations:
 
     Attributes:
         events: The instances that write to the event and backfill streams.
-        typing: The instance that writes to the typing stream.
+        typing: The instances that write to the typing stream. Currently
+            can only be a single instance.
         to_device: The instances that write to the to_device stream. Currently
             can only be a single instance.
         account_data: The instances that write to the account data streams. Currently
@@ -75,9 +76,15 @@ class WriterLocations:
     """
 
     events = attr.ib(
-        default=["master"], type=List[str], converter=_instance_to_list_converter
+        default=["master"],
+        type=List[str],
+        converter=_instance_to_list_converter,
+    )
+    typing = attr.ib(
+        default=["master"],
+        type=List[str],
+        converter=_instance_to_list_converter,
     )
-    typing = attr.ib(default="master", type=str)
     to_device = attr.ib(
         default=["master"],
         type=List[str],
@@ -217,6 +224,11 @@ class WorkerConfig(Config):
                         % (instance, stream)
                     )
 
+        if len(self.writers.typing) != 1:
+            raise ConfigError(
+                "Must only specify one instance to handle `typing` messages."
+            )
+
         if len(self.writers.to_device) != 1:
             raise ConfigError(
                 "Must only specify one instance to handle `to_device` messages."
diff --git a/synapse/federation/federation_server.py b/synapse/federation/federation_server.py
index 32a75993d9..42e3acecb4 100644
--- a/synapse/federation/federation_server.py
+++ b/synapse/federation/federation_server.py
@@ -1232,10 +1232,6 @@ class FederationHandlerRegistry:
 
         self.query_handlers[query_type] = handler
 
-    def register_instance_for_edu(self, edu_type: str, instance_name: str) -> None:
-        """Register that the EDU handler is on a different instance than master."""
-        self._edu_type_to_instance[edu_type] = [instance_name]
-
     def register_instances_for_edu(
         self, edu_type: str, instance_names: List[str]
     ) -> None:
diff --git a/synapse/handlers/typing.py b/synapse/handlers/typing.py
index c411d69924..22c6174821 100644
--- a/synapse/handlers/typing.py
+++ b/synapse/handlers/typing.py
@@ -62,8 +62,8 @@ class FollowerTypingHandler:
         if hs.should_send_federation():
             self.federation = hs.get_federation_sender()
 
-        if hs.config.worker.writers.typing != hs.get_instance_name():
-            hs.get_federation_registry().register_instance_for_edu(
+        if hs.get_instance_name() not in hs.config.worker.writers.typing:
+            hs.get_federation_registry().register_instances_for_edu(
                 "m.typing",
                 hs.config.worker.writers.typing,
             )
@@ -205,7 +205,7 @@ class TypingWriterHandler(FollowerTypingHandler):
     def __init__(self, hs: "HomeServer"):
         super().__init__(hs)
 
-        assert hs.config.worker.writers.typing == hs.get_instance_name()
+        assert hs.get_instance_name() in hs.config.worker.writers.typing
 
         self.auth = hs.get_auth()
         self.notifier = hs.get_notifier()
diff --git a/synapse/replication/tcp/handler.py b/synapse/replication/tcp/handler.py
index 06fd06fdf3..21293038ef 100644
--- a/synapse/replication/tcp/handler.py
+++ b/synapse/replication/tcp/handler.py
@@ -138,7 +138,7 @@ class ReplicationCommandHandler:
             if isinstance(stream, TypingStream):
                 # Only add TypingStream as a source on the instance in charge of
                 # typing.
-                if hs.config.worker.writers.typing == hs.get_instance_name():
+                if hs.get_instance_name() in hs.config.worker.writers.typing:
                     self._streams_to_replicate.append(stream)
 
                 continue
diff --git a/synapse/replication/tcp/streams/_base.py b/synapse/replication/tcp/streams/_base.py
index c8b188ae4e..743a01da08 100644
--- a/synapse/replication/tcp/streams/_base.py
+++ b/synapse/replication/tcp/streams/_base.py
@@ -328,8 +328,7 @@ class TypingStream(Stream):
     ROW_TYPE = TypingStreamRow
 
     def __init__(self, hs: "HomeServer"):
-        writer_instance = hs.config.worker.writers.typing
-        if writer_instance == hs.get_instance_name():
+        if hs.get_instance_name() in hs.config.worker.writers.typing:
             # On the writer, query the typing handler
             typing_writer_handler = hs.get_typing_writer_handler()
             update_function: Callable[
diff --git a/synapse/rest/client/room.py b/synapse/rest/client/room.py
index ed95189b6d..6a876cfa2f 100644
--- a/synapse/rest/client/room.py
+++ b/synapse/rest/client/room.py
@@ -914,7 +914,7 @@ class RoomTypingRestServlet(RestServlet):
         # If we're not on the typing writer instance we should scream if we get
         # requests.
         self._is_typing_writer = (
-            hs.config.worker.writers.typing == hs.get_instance_name()
+            hs.get_instance_name() in hs.config.worker.writers.typing
         )
 
     async def on_PUT(
diff --git a/synapse/server.py b/synapse/server.py
index 0fbf36ba99..013a7bacaa 100644
--- a/synapse/server.py
+++ b/synapse/server.py
@@ -463,7 +463,7 @@ class HomeServer(metaclass=abc.ABCMeta):
 
     @cache_in_self
     def get_typing_writer_handler(self) -> TypingWriterHandler:
-        if self.config.worker.writers.typing == self.get_instance_name():
+        if self.get_instance_name() in self.config.worker.writers.typing:
             return TypingWriterHandler(self)
         else:
             raise Exception("Workers cannot write typing")
@@ -474,7 +474,7 @@ class HomeServer(metaclass=abc.ABCMeta):
 
     @cache_in_self
     def get_typing_handler(self) -> FollowerTypingHandler:
-        if self.config.worker.writers.typing == self.get_instance_name():
+        if self.get_instance_name() in self.config.worker.writers.typing:
             # Use get_typing_writer_handler to ensure that we use the same
             # cached version.
             return self.get_typing_writer_handler()