Merge "Make the cron trigger execution interval configurable"

mistral/config.py

@@ -251,6 +251,20 @@ cron_trigger_opts = [
             ' performance.'
         )
     ),
+    cfg.IntOpt(
+        'execution_interval',
+        default=1,
+        min=1,
+        help=(
+            'This setting defines how frequently Mistral checks for cron ',
+            'triggers that need execution. By default this is every second ',
+            'which can lead to high system load. Increasing the number will ',
+            'reduce the load but also limit the minimum freqency. For ',
+            'example, a cron trigger can be configured to run every second ',
+            'but if the execution_interval is set to 60, it will only run ',
+            'once per minute.'
+        )
+    )
 ]
 
 event_engine_opts = [

mistral/services/periodic.py

@@ -35,7 +35,8 @@ _periodic_tasks = {}
 
 
 class MistralPeriodicTasks(periodic_task.PeriodicTasks):
-    @periodic_task.periodic_task(spacing=1, run_immediately=True)
+    @periodic_task.periodic_task(spacing=CONF.cron_trigger.execution_interval,
+                                 run_immediately=True)
     def process_cron_triggers_v2(self, ctx):
         LOG.debug("Processing cron triggers...")