From b085f3bec5179ed568245b360a85f15b1ddb9f68 Mon Sep 17 00:00:00 2001
From: damencho <damencho@jitsi.org>
Date: Tue, 12 Dec 2023 10:34:26 -0600
Subject: [PATCH] feat: Adds detection of occupants with no connection.

We saw recently two occasions with rooms with participants but no prosody.full_sessions for those participants and when everyone leaves the meeting it never ends.
---
 resources/prosody-plugins/mod_muc_census.lua | 33 ++++++++++++++++++--
 1 file changed, 30 insertions(+), 3 deletions(-)

diff --git a/resources/prosody-plugins/mod_muc_census.lua b/resources/prosody-plugins/mod_muc_census.lua
index 5b466e6228b8..b63f3f501c6e 100644
--- a/resources/prosody-plugins/mod_muc_census.lua
+++ b/resources/prosody-plugins/mod_muc_census.lua
@@ -37,6 +37,8 @@ local tostring = tostring;
 -- required parameter for custom muc component prefix, defaults to "conference"
 local muc_domain_prefix = module:get_option_string("muc_mapper_domain_prefix", "conference");
 
+local leaked_rooms_since_last_stat = 0;
+
 --- handles request to get number of participants in all rooms
 -- @return GET response
 function handle_get_room_census(event)
@@ -49,15 +51,33 @@ function handle_get_room_census(event)
     for room in host_session.modules.muc.each_room() do
         if not is_healthcheck_room(room.jid) then
             local occupants = room._occupants;
+            local participant_count = 0;
+            local missing_connections_count = 0;
+
             if occupants then
-                participant_count = iterators.count(room:each_occupant()) - 1; -- subtract focus
-            else
-                participant_count = 0
+                for _, o in room:each_occupant() do
+                    participant_count = participant_count + 1;
+
+                    -- let's check whether that occupant has connection in the full_sessions of prosody
+                    -- attempt to detect leaked occupants/rooms.
+                    if prosody.full_sessions[o.jid] == nil then
+                        missing_connections_count = missing_connections_count + 1;
+                    end
+                end
+                participant_count = participant_count - 1; -- subtract focus
             end
+
+            local leaked = false;
+            if participant_count > 0 and missing_connections_count == participant_count then
+                leaked = true;
+                leaked_rooms_since_last_stat = leaked_rooms_since_last_stat + 1;
+            end
+
             table.insert(room_data, {
                 room_name = room.jid;
                 participants = participant_count;
                 created_time = room.created_timestamp;
+                leaked = leaked;
             });
         end
     end
@@ -77,3 +97,10 @@ function module.load()
                 };
         });
 end
+
+-- we calculate the stats on the configured interval (60 seconds by default)
+local measure_leaked_rooms = module:measure('leaked_rooms', 'amount');
+module:hook_global('stats-update', function ()
+    measure_leaked_rooms(leaked_rooms_since_last_stat);
+    leaked_rooms_since_last_stat = 0;
+end);