Merge pull request #1908 from Netflix/event_processor_extension

Allow customization of handling transient failures

core/src/main/java/com/netflix/conductor/core/events/SimpleEventProcessor.java

@@ -208,14 +208,24 @@ protected List<EventExecution> executeEvent(String event, Message msg) throws Ex
             CompletableFuture<List<EventExecution>> future = executeActionsForEventHandler(eventHandler, msg);
             future.whenComplete((result, error) -> result.forEach(eventExecution -> {
                 if (error != null || eventExecution.getStatus() == Status.IN_PROGRESS) {
-                    executionService.removeEventExecution(eventExecution);
                     transientFailures.add(eventExecution);
                 } else {
                     executionService.updateEventExecution(eventExecution);
                 }
             })).get();
         }
-        return transientFailures;
+        return processTransientFailures(transientFailures);
+    }
+
+    /**
+     * Remove the event executions which failed temporarily.
+     *
+     * @param eventExecutions The event executions which failed with a transient error.
+     * @return The event executions which failed with a transient error.
+     */
+    protected List<EventExecution> processTransientFailures(List<EventExecution> eventExecutions) {
+        eventExecutions.forEach(executionService::removeEventExecution);
+        return eventExecutions;
     }
 
     /**