Fix tightloop on sending transaction

synapse/federation/transaction_queue.py

@@ -209,11 +209,13 @@ class TransactionQueue(object):
                         )
                         return
 
-                    yield self._send_new_transaction(
+                    success = yield self._send_new_transaction(
                         destination, pending_pdus, pending_edus, pending_failures,
                         device_stream_id,
                         should_delete_from_device_stream=bool(device_message_edus)
                     )
+                    if not success:
+                        break
         finally:
             # We want to be *very* sure we delete this after we stop processing
             self.pending_transactions.pop(destination, None)
@@ -248,6 +250,8 @@ class TransactionQueue(object):
         edus = pending_edus
         failures = [x.get_dict() for x in pending_failures]
 
+        success = True
+
         try:
             logger.debug("TX [%s] _attempt_new_transaction", destination)
 
@@ -347,6 +351,7 @@ class TransactionQueue(object):
                     logger.info(
                         "Failed to send event %s to %s", p.event_id, destination
                     )
+                success = False
             else:
                 # Remove the acknowledged device messages from the database
                 if should_delete_from_device_stream:
@@ -360,6 +365,7 @@ class TransactionQueue(object):
                 "dropping transaction for now",
                 destination,
             )
+            success = False
         except RuntimeError as e:
             # We capture this here as there as nothing actually listens
             # for this finishing functions deferred.
@@ -369,6 +375,8 @@ class TransactionQueue(object):
                 e,
             )
 
+            success = False
+
             for p in pdus:
                 logger.info("Failed to send event %s to %s", p.event_id, destination)
         except Exception as e:
@@ -380,5 +388,9 @@ class TransactionQueue(object):
                 e,
             )
 
+            success = False
+
             for p in pdus:
                 logger.info("Failed to send event %s to %s", p.event_id, destination)
+
+        defer.returnValue(success)