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, 16 insertions, 2 deletions

diff --git a/synapse/federation/sender/__init__.py b/synapse/federation/sender/__init__.py

index 4ebb0e8bc0..36c83c3027 100644
--- a/synapse/federation/sender/__init__.py
+++ b/synapse/federation/sender/__init__.py
@@ -21,6 +21,7 @@ from prometheus_client import Counter
 
 from twisted.internet import defer
 
+import synapse
 import synapse.metrics
 from synapse.federation.sender.per_destination_queue import PerDestinationQueue
 from synapse.federation.sender.transaction_manager import TransactionManager
@@ -54,7 +55,7 @@ sent_pdus_destination_dist_total = Counter(
 
 
 class FederationSender(object):
-    def __init__(self, hs):
+    def __init__(self, hs: "synapse.server.HomeServer"):
         self.hs = hs
         self.server_name = hs.hostname
 
@@ -482,7 +483,20 @@ class FederationSender(object):
 
     def send_device_messages(self, destination):
         if destination == self.server_name:
-            logger.info("Not sending device update to ourselves")
+            logger.warning("Not sending device update to ourselves")
+            return
+
+        self._get_per_destination_queue(destination).attempt_new_transaction()
+
+    def wake_destination(self, destination: str):
+        """Called when we want to retry sending transactions to a remote.
+
+        This is mainly useful if the remote server has been down and we think it
+        might have come back.
+        """
+
+        if destination == self.server_name:
+            logger.warning("Not waking up ourselves")
             return
 
         self._get_per_destination_queue(destination).attempt_new_transaction()