Displaying roll back reason after both ROLLBACK_COMPLETE or UPDATE_ROLLBACK_COMPLETE

Author: Garison Draper

stacker/actions/build.py

@@ -310,8 +310,11 @@ def _launch_stack(self, stack, **kwargs):
                 reason = old_status.reason
                 if 'rolling' in reason:
                     reason = reason.replace('rolling', 'rolled')
-
+                status_reason = provider.get_rollback_status_reason(stack.fqn)
+                logger.info(
+                    "%s Stack Roll Back Reason: " + status_reason, stack.fqn)
                 return FailedStatus(reason)
+
             elif provider.is_stack_completed(provider_stack):
                 stack.set_outputs(
                     provider.get_output_dict(provider_stack))

stacker/providers/aws/default.py

@@ -624,7 +624,7 @@ def _tail_print(e):
                             e['ResourceType'],
                             e['EventId']))
 
-    def get_events(self, stack_name):
+    def get_events(self, stack_name, chronological=True):
         """Get the events in batches and return in chronological order"""
         next_token = None
         event_list = []
@@ -642,7 +642,25 @@ def get_events(self, stack_name):
             if next_token is None:
                 break
             time.sleep(GET_EVENTS_SLEEP)
-        return reversed(sum(event_list, []))
+        if chronological:
+            return reversed(sum(event_list, []))
+        else:
+            return sum(event_list, [])
+
+    def get_rollback_status_reason(self, stack_name):
+        """Process events and returns latest roll back reason"""
+        event = next((item for item in self.get_events(stack_name,
+                      False) if item["ResourceStatus"] ==
+                      "UPDATE_ROLLBACK_IN_PROGRESS"), None)
+        if event:
+            reason = event["ResourceStatusReason"]
+            return reason
+        else:
+            event = next((item for item in self.get_events(stack_name)
+                          if item["ResourceStatus"] ==
+                          "ROLLBACK_IN_PROGRESS"), None)
+            reason = event["ResourceStatusReason"]
+            return reason
 
     def tail(self, stack_name, cancel, log_func=_tail_print, sleep_time=5,
              include_initial=True):