From 8942e23a6941dc740f6f703f7e353f273874f104 Mon Sep 17 00:00:00 2001
From: 14mRh4X0r <14mRh4X0r@gmail.com>
Date: Mon, 7 Jun 2021 16:42:05 +0200
Subject: Always update AS last_pos, even on no events (#10107)

Fixes #1834.

`get_new_events_for_appservice` internally calls `get_events_as_list`, which will filter out any rejected events. If all returned events are filtered out, `_notify_interested_services` will return without updating the last handled stream position. If there are 100 consecutive such events, processing will halt altogether.

Breaking the loop is now done by checking whether we're up-to-date with `current_max` in the loop condition, instead of relying on an empty `events` list.


Signed-off-by: Willem Mulder <14mRh4X0r@gmail.com>
---
 synapse/handlers/appservice.py | 25 ++++++++++++-------------
 1 file changed, 12 insertions(+), 13 deletions(-)

(limited to 'synapse')

diff --git a/synapse/handlers/appservice.py b/synapse/handlers/appservice.py
index 177310f0be..862638cc4f 100644
--- a/synapse/handlers/appservice.py
+++ b/synapse/handlers/appservice.py
@@ -87,7 +87,8 @@ class ApplicationServicesHandler:
             self.is_processing = True
             try:
                 limit = 100
-                while True:
+                upper_bound = -1
+                while upper_bound < self.current_max:
                     (
                         upper_bound,
                         events,
@@ -95,9 +96,6 @@ class ApplicationServicesHandler:
                         self.current_max, limit
                     )
 
-                    if not events:
-                        break
-
                     events_by_room = {}  # type: Dict[str, List[EventBase]]
                     for event in events:
                         events_by_room.setdefault(event.room_id, []).append(event)
@@ -153,9 +151,6 @@ class ApplicationServicesHandler:
 
                     await self.store.set_appservice_last_pos(upper_bound)
 
-                    now = self.clock.time_msec()
-                    ts = await self.store.get_received_ts(events[-1].event_id)
-
                     synapse.metrics.event_processing_positions.labels(
                         "appservice_sender"
                     ).set(upper_bound)
@@ -168,12 +163,16 @@ class ApplicationServicesHandler:
 
                     event_processing_loop_counter.labels("appservice_sender").inc()
 
-                    synapse.metrics.event_processing_lag.labels(
-                        "appservice_sender"
-                    ).set(now - ts)
-                    synapse.metrics.event_processing_last_ts.labels(
-                        "appservice_sender"
-                    ).set(ts)
+                    if events:
+                        now = self.clock.time_msec()
+                        ts = await self.store.get_received_ts(events[-1].event_id)
+
+                        synapse.metrics.event_processing_lag.labels(
+                            "appservice_sender"
+                        ).set(now - ts)
+                        synapse.metrics.event_processing_last_ts.labels(
+                            "appservice_sender"
+                        ).set(ts)
             finally:
                 self.is_processing = False
 
-- 
cgit 1.4.1