Wake up transaction queue when remote server comes back online (#6706)

This will be used to retry outbound transactions to a remote server if
we think it might have come back up.

1 files changed, 9 insertions, 0 deletions

diff --git a/synapse/replication/tcp/resource.py b/synapse/replication/tcp/resource.py
index b1752e88cd..6ebf944f66 100644
--- a/synapse/replication/tcp/resource.py
+++ b/synapse/replication/tcp/resource.py
@@ -120,6 +120,7 @@ class ReplicationStreamer(object):
             self.federation_sender = hs.get_federation_sender()
 
         self.notifier.add_replication_callback(self.on_notifier_poke)
+        self.notifier.add_remote_server_up_callback(self.send_remote_server_up)
 
         # Keeps track of whether we are currently checking for updates
         self.is_looping = False
@@ -288,6 +289,14 @@ class ReplicationStreamer(object):
         )
         await self._server_notices_sender.on_user_ip(user_id)
 
+    @measure_func("repl.on_remote_server_up")
+    def on_remote_server_up(self, server: str):
+        self.notifier.notify_remote_server_up(server)
+
+    def send_remote_server_up(self, server: str):
+        for conn in self.connections:
+            conn.send_remote_server_up(server)
+
     def send_sync_to_all_connections(self, data):
         """Sends a SYNC command to all clients.