Fix `PeriodicCallback' when callback function return `Future' and has

`Exception' will silence ignore

diff --git a/tornado/ioloop.py b/tornado/ioloop.py
index 738cc96440ecc60da71764c0e1801d0f23da8023..e15252d3450c779ca3b124db4da0a6840314b8ae 100644 (file)
--- a/tornado/ioloop.py
+++ b/tornado/ioloop.py
@@ -969,10 +969,11 @@ class PeriodicCallback(object):
         if not self._running:
             return
         try:
-            self.callback()
+            return self.callback()
         except Exception:
             self.io_loop.handle_callback_exception(self.callback)
-        self._schedule_next()
+        finally:
+            self._schedule_next()
 
     def _schedule_next(self):
         if self._running: