mgr/dashboard: fix type error in get_rate function

Fixes: http://tracker.ceph.com/issues/20276
Signed-off-by: liuchang0812 <liuchang0812@gmail.com>

diff --git a/src/pybind/mgr/dashboard/module.py b/src/pybind/mgr/dashboard/module.py
index df0437da550b50638a4a02d9d6f8cdb535e86c51..78eeb7cbe98d55bc1c50c390eeb209692e805974 100644 (file)
--- a/src/pybind/mgr/dashboard/module.py
+++ b/src/pybind/mgr/dashboard/module.py
@@ -610,7 +610,7 @@ class Module(MgrModule):
 
                     def get_rate(series):
                         if len(series) >= 2:
-                            return (series[0][1] - series[1][1]) / float(series[0][0] - series[1][0])
+                            return (float(series[0][1]) - float(series[1][1])) / (float(series[0][0]) - float(series[1][0]))
                         else:
                             return 0