tornado: Use spiffy new `call_later` rather than `add_timeout`.

This method was new in Tornado 4.0.  It saves us from having to get
the time ourselves and do the arithmetic -- which not only makes the
code a bit shorter, but also easier to get right.  Tornado docs (see
http://www.tornadoweb.org/en/stable/ioloop.html) say we should have
been getting the time from `ioloop.time()` rather than hardcoding
`time.time()`, because the loop could e.g. be running on the
`time.monotonic()` clock.

tools/run-dev.py

@@ -380,7 +380,7 @@ def shutdown_handler(*args, **kwargs):
     # type: (*Any, **Any) -> None
     io_loop = IOLoop.instance()
     if io_loop._callbacks:
-        io_loop.add_timeout(time.time() + 1, shutdown_handler)
+        io_loop.call_later(1, shutdown_handler)
     else:
         io_loop.stop()
 

zerver/lib/queue.py

@@ -221,9 +221,9 @@ class TornadoQueueClient(SimpleQueueClient):
                 self._reconnect()
             except pika.exceptions.AMQPConnectionError:
                 self.log.critical("Failed to reconnect to RabbitMQ, retrying...")
-                ioloop.IOLoop.instance().add_timeout(time.time() + retry_seconds, on_timeout)
+                ioloop.IOLoop.instance().call_later(retry_seconds, on_timeout)
 
-        ioloop.IOLoop.instance().add_timeout(time.time() + retry_seconds, on_timeout)
+        ioloop.IOLoop.instance().call_later(retry_seconds, on_timeout)
 
     def ensure_queue(self, queue_name: str, callback: Callable[[], None]) -> None:
         def finish(frame: Any) -> None:

zerver/tornado/event_queue.py

@@ -78,7 +78,7 @@ class ClientDescriptor:
         self.client_gravatar = client_gravatar
         self.all_public_streams = all_public_streams
         self.client_type_name = client_type_name
-        self._timeout_handle = None  # type: Any # TODO: should be return type of ioloop.add_timeout
+        self._timeout_handle = None  # type: Any # TODO: should be return type of ioloop.call_later
         self.narrow = narrow
         self.narrow_filter = build_narrow_filter(narrow)
 
@@ -189,9 +189,9 @@ class ClientDescriptor:
             # All clients get heartbeat events
             self.add_event(dict(type='heartbeat'))
         ioloop = tornado.ioloop.IOLoop.instance()
-        heartbeat_time = time.time() + HEARTBEAT_MIN_FREQ_SECS + random.randint(0, 10)
+        interval = HEARTBEAT_MIN_FREQ_SECS + random.randint(0, 10)
         if self.client_type_name != 'API: heartbeat test':
-            self._timeout_handle = ioloop.add_timeout(heartbeat_time, timeout_callback)
+            self._timeout_handle = ioloop.call_later(interval, timeout_callback)
 
     def disconnect_handler(self, client_closed: bool=False) -> None:
         if self.current_handler_id:

zerver/tornado/socket.py

@@ -103,7 +103,7 @@ class SocketConnection(sockjs.tornado.SockJSConnection):
             self.close_info = CloseErrorInfo(408, "Timeout while waiting for authentication")
             self.close()
 
-        self.timeout_handle = ioloop.add_timeout(time.time() + 10, auth_timeout)
+        self.timeout_handle = ioloop.call_later(10, auth_timeout)
         write_log_line(log_data, path='/socket/open', method='SOCKET',
                        remote_ip=info.ip, email='unknown', client_name='?')