Add stop_on_exception to TG timers

ThreadGroup add_dynamic_timer_args and add_timer_args use
DynamicLoopingCall and FixedIntervalLoopingCall respectively.  Both
classes have support for stop_on_exception, but this parameter was not
exposed in ThreadGroup functions to create timers.

This change adds the missing stop_on_exception to the timer functions so
that ThreadGroup timers can continue on exceptions if the user chooses
to do so.

Change-Id: If03276f290e86e95ddc0b1d749b7460ed752b8ef
Co-Authored-By: Zane Bitter <zbitter@redhat.com>

oslo_service/tests/test_threadgroup.py

@@ -55,7 +55,8 @@ class ThreadGroupTestCase(test_base.BaseTestCase):
 
         self.tg.add_dynamic_timer_args(foo, ['arg'], {'kwarg': 'kwarg'},
                                        initial_delay=1,
-                                       periodic_interval_max=2)
+                                       periodic_interval_max=2,
+                                       stop_on_exception=False)
 
         self.assertEqual(1, len(self.tg.timers))
 
@@ -83,7 +84,7 @@ class ThreadGroupTestCase(test_base.BaseTestCase):
             pass
 
         self.tg.add_timer_args(1, foo, ['arg'], {'kwarg': 'kwarg'},
-                               initial_delay=1)
+                               initial_delay=1, stop_on_exception=False)
 
         self.assertEqual(1, len(self.tg.timers))
 

oslo_service/threadgroup.py

@@ -89,12 +89,14 @@ class ThreadGroup(object):
             periodic_interval_max=periodic_interval_max)
 
     def add_dynamic_timer_args(self, callback, args=None, kwargs=None,
-                               initial_delay=None, periodic_interval_max=None):
+                               initial_delay=None, periodic_interval_max=None,
+                               stop_on_exception=True):
         args = args or []
         kwargs = kwargs or {}
         timer = loopingcall.DynamicLoopingCall(callback, *args, **kwargs)
         timer.start(initial_delay=initial_delay,
-                    periodic_interval_max=periodic_interval_max)
+                    periodic_interval_max=periodic_interval_max,
+                    stop_on_exception=stop_on_exception)
         self.timers.append(timer)
         return timer
 
@@ -109,12 +111,13 @@ class ThreadGroup(object):
                                    initial_delay=initial_delay)
 
     def add_timer_args(self, interval, callback, args=None, kwargs=None,
-                       initial_delay=None):
+                       initial_delay=None, stop_on_exception=True):
         args = args or []
         kwargs = kwargs or {}
         pulse = loopingcall.FixedIntervalLoopingCall(callback, *args, **kwargs)
         pulse.start(interval=interval,
-                    initial_delay=initial_delay)
+                    initial_delay=initial_delay,
+                    stop_on_exception=stop_on_exception)
         self.timers.append(pulse)
         return pulse
 

releasenotes/notes/timer-stop_on_exception-9f21d7c4d6d1b0d9.yaml

@@ -0,0 +1,6 @@
+---
+features:
+  - |
+    The ThreadGroup add_timer_args() and add_dynamic_timer_args() methods now
+    support passing a stop_on_exception=False argument to allow the timer to
+    keep running even when an exception is raised by the callback function.