[FIX] bus: fix websocket timeout burst

Before this commit, the keep alive timeout could occur for many websockets at
the same time resulting in a burst of transaction (cursor is open when connecting,
disconnecting a websocket).

This issue was even worse because the cursor was opened even when it was
not needed: we don't need to open a cursor if there is no callback
registered for the lifecycle event (OPEN/CLOSE).

This commit fixes those issues by:
- adding a random delay to the keep alive timeout of every websocket.
- not triggering lifecycle events if no callbacks are registered.

closes odoo/odoo#110127

X-original-commit: b4fb1359021b6c882ece3037c82aaaf65cfc2e1e
Signed-off-by: Julien Castiaux <juc@odoo.com>

addons/bus/tests/test_websocket_caryall.py

@@ -88,9 +88,9 @@ class TestWebsocketCaryall(WebsocketCase):
     def test_timeout_manager_keep_alive_timeout(self):
         with freeze_time('2022-08-19') as frozen_time:
             timeout_manager = TimeoutManager()
-            frozen_time.tick(delta=timedelta(seconds=TimeoutManager.KEEP_ALIVE_TIMEOUT / 2))
+            frozen_time.tick(delta=timedelta(seconds=timeout_manager._keep_alive_timeout / 2))
             self.assertFalse(timeout_manager.has_timed_out())
-            frozen_time.tick(delta=timedelta(seconds=TimeoutManager.KEEP_ALIVE_TIMEOUT / 2))
+            frozen_time.tick(delta=timedelta(seconds=timeout_manager._keep_alive_timeout / 2 + 1))
             self.assertTrue(timeout_manager.has_timed_out())
             self.assertEqual(timeout_manager.timeout_reason, TimeoutReason.KEEP_ALIVE)
 
@@ -284,3 +284,9 @@ class TestWebsocketCaryall(WebsocketCase):
                 'data': {'channels': ['my_channel'], 'last': client_last_notification_id}
             }))
             subscribe_done_event.wait()
+
+    def test_no_cursor_when_no_callback_for_lifecycle_event(self):
+        with patch.object(Websocket, '_event_callbacks', defaultdict(set)):
+            with patch('odoo.addons.bus.websocket.acquire_cursor') as mock:
+                self.websocket_connect()
+                self.assertFalse(mock.called)

addons/bus/websocket.py

@@ -602,6 +602,8 @@ class Websocket:
         registered for this event type. Every callback is given both the
         environment and the related websocket.
         """
+        if not type(self)._event_callbacks[event_type]:
+            return
         with closing(acquire_cursor(self._session.db)) as cr:
             env = api.Environment(cr, self._session.uid, self._session.context)
             for callback in type(self)._event_callbacks[event_type]:
@@ -646,8 +648,8 @@ class TimeoutManager:
     """
     This class handles the Websocket timeouts. If no response to a
     PING/CLOSE frame is received after `TIMEOUT` seconds or if the
-    connection is opened for more than `KEEP_ALIVE_TIMEOUT` seconds, the
-    connection is considered to have timed out. To determine if the
+    connection is opened for more than `self._keep_alive_timeout` seconds,
+    the connection is considered to have timed out. To determine if the
     connection has timed out, use the `has_timed_out` method.
     """
     TIMEOUT = 15
@@ -660,6 +662,11 @@ class TimeoutManager:
         self._awaited_opcode = None
         # Time in which the connection was opened.
         self._opened_at = time.time()
+        # Custom keep alive timeout for each TimeoutManager to avoid multiple
+        # connections timing out at the same time.
+        self._keep_alive_timeout = (
+            type(self).KEEP_ALIVE_TIMEOUT + random.uniform(0, type(self).KEEP_ALIVE_TIMEOUT / 2)
+        )
         self.timeout_reason = None
         # Start time recorded when we started awaiting an answer to a
         # PING/CLOSE frame.
@@ -689,10 +696,10 @@ class TimeoutManager:
         Determine whether the connection has timed out or not. The
         connection times out when the answer to a CLOSE/PING frame
         is not received within `TIMEOUT` seconds or if the connection
-        is opened for more than `KEEP_ALIVE_TIMEOUT` seconds.
+        is opened for more than `self._keep_alive_timeout` seconds.
         """
         now = time.time()
-        if now - self._opened_at >= type(self).KEEP_ALIVE_TIMEOUT:
+        if now - self._opened_at >= self._keep_alive_timeout:
             self.timeout_reason = TimeoutReason.KEEP_ALIVE
             return True
         if self._awaited_opcode and now - self._waiting_start_time >= type(self).TIMEOUT: