Alerting: Create annotation if Firing alert is removed (#45703)

This commit changes staleResultsHandler to create an annotation if the current state is Alerting and the result is being removed from the state cache as it has not been updated since 2x the evaluation interval.

pkg/services/ngalert/state/manager.go

@@ -189,7 +189,7 @@ func (st *Manager) setNextState(ctx context.Context, alertRule *ngModels.AlertRu
 
 	st.set(currentState)
 	if oldState != currentState.State {
-		go st.createAlertAnnotation(ctx, alertRule, currentState.Labels, result.EvaluatedAt, currentState.State, oldState)
+		go st.annotateState(ctx, alertRule, currentState.Labels, result.EvaluatedAt, currentState.State, oldState)
 	}
 	return currentState
 }
@@ -237,7 +237,7 @@ func translateInstanceState(state ngModels.InstanceStateType) eval.State {
 	}
 }
 
-func (st *Manager) createAlertAnnotation(ctx context.Context, alertRule *ngModels.AlertRule, labels data.Labels, evaluatedAt time.Time, state eval.State, previousState eval.State) {
+func (st *Manager) annotateState(ctx context.Context, alertRule *ngModels.AlertRule, labels data.Labels, evaluatedAt time.Time, state eval.State, previousState eval.State) {
 	st.log.Debug("alert state changed creating annotation", "alertRuleUID", alertRule.UID, "newState", state.String(), "oldState", previousState.String())
 
 	labels = removePrivateLabels(labels)
@@ -300,6 +300,10 @@ func (st *Manager) staleResultsHandler(ctx context.Context, alertRule *ngModels.
 			if err = st.instanceStore.DeleteAlertInstance(ctx, s.OrgID, s.AlertRuleUID, labelsHash); err != nil {
 				st.log.Error("unable to delete stale instance from database", "error", err.Error(), "orgID", s.OrgID, "alertRuleUID", s.AlertRuleUID, "cacheID", s.CacheId)
 			}
+
+			if s.State == eval.Alerting {
+				st.annotateState(ctx, alertRule, s.Labels, time.Now(), eval.Normal, s.State)
+			}
 		}
 	}
 }