Merge pull request #4749 from matrix-org/erikj/replication_connection_backoff

Fix tightloop over connecting to replication server

1 files changed, 18 insertions, 4 deletions

diff --git a/synapse/replication/tcp/client.py b/synapse/replication/tcp/client.py
index 586dddb40b..e558f90e1a 100644
--- a/synapse/replication/tcp/client.py
+++ b/synapse/replication/tcp/client.py
@@ -39,7 +39,7 @@ class ReplicationClientFactory(ReconnectingClientFactory):
     Accepts a handler that will be called when new data is available or data
     is required.
     """
-    maxDelay = 5  # Try at least once every N seconds
+    maxDelay = 30  # Try at least once every N seconds
 
     def __init__(self, hs, client_name, handler):
         self.client_name = client_name
@@ -54,7 +54,6 @@ class ReplicationClientFactory(ReconnectingClientFactory):
 
     def buildProtocol(self, addr):
         logger.info("Connected to replication: %r", addr)
-        self.resetDelay()
         return ClientReplicationStreamProtocol(
             self.client_name, self.server_name, self._clock, self.handler
         )
@@ -90,15 +89,18 @@ class ReplicationClientHandler(object):
         # Used for tests.
         self.awaiting_syncs = {}
 
+        # The factory used to create connections.
+        self.factory = None
+
     def start_replication(self, hs):
         """Helper method to start a replication connection to the remote server
         using TCP.
         """
         client_name = hs.config.worker_name
-        factory = ReplicationClientFactory(hs, client_name, self)
+        self.factory = ReplicationClientFactory(hs, client_name, self)
         host = hs.config.worker_replication_host
         port = hs.config.worker_replication_port
-        hs.get_reactor().connectTCP(host, port, factory)
+        hs.get_reactor().connectTCP(host, port, self.factory)
 
     def on_rdata(self, stream_name, token, rows):
         """Called when we get new replication data. By default this just pokes
@@ -140,6 +142,7 @@ class ReplicationClientHandler(object):
             args["account_data"] = user_account_data
         elif room_account_data:
             args["account_data"] = room_account_data
+
         return args
 
     def get_currently_syncing_users(self):
@@ -204,3 +207,14 @@ class ReplicationClientHandler(object):
             for cmd in self.pending_commands:
                 connection.send_command(cmd)
             self.pending_commands = []
+
+    def finished_connecting(self):
+        """Called when we have successfully subscribed and caught up to all
+        streams we're interested in.
+        """
+        logger.info("Finished connecting to server")
+
+        # We don't reset the delay any earlier as otherwise if there is a
+        # problem during start up we'll end up tight looping connecting to the
+        # server.
+        self.factory.resetDelay()