fix(autoscale): Fix when making CFN update, an autoscaled instance should not fail the CFN deploy

aws-rds-dbinstance/src/main/java/software/amazon/rds/dbinstance/BaseHandlerStd.java

@@ -386,12 +386,14 @@ protected ProgressEvent<ResourceModel, CallbackContext> updateDbInstance(
             final AmazonWebServicesClientProxy proxy,
             final ResourceHandlerRequest<ResourceModel> request,
             final ProxyClient<RdsClient> rdsProxyClient,
-            final ProgressEvent<ResourceModel, CallbackContext> progress
+            final ProgressEvent<ResourceModel, CallbackContext> progress,
+            final DBInstance dbInstance
     ) {
         return proxy.initiate("rds::modify-db-instance", rdsProxyClient, progress.getResourceModel(), progress.getCallbackContext())
                 .translateToServiceRequest(resourceModel -> Translator.modifyDbInstanceRequest(
                         request.getPreviousResourceState(),
                         request.getDesiredResourceState(),
+                        dbInstance,
                         BooleanUtils.isTrue(request.getRollback()))
                 )
                 .backoffDelay(config.getBackoff())

aws-rds-dbinstance/src/main/java/software/amazon/rds/dbinstance/Translator.java

@@ -28,6 +28,7 @@
 import software.amazon.awssdk.services.rds.model.CloudwatchLogsExportConfiguration;
 import software.amazon.awssdk.services.rds.model.CreateDbInstanceReadReplicaRequest;
 import software.amazon.awssdk.services.rds.model.CreateDbInstanceRequest;
+import software.amazon.awssdk.services.rds.model.DBInstance;
 import software.amazon.awssdk.services.rds.model.DeleteDbInstanceRequest;
 import software.amazon.awssdk.services.rds.model.DescribeDbClusterSnapshotsRequest;
 import software.amazon.awssdk.services.rds.model.DescribeDbClustersRequest;
@@ -46,6 +47,7 @@
 import software.amazon.awssdk.services.rds.model.StartDbInstanceAutomatedBackupsReplicationRequest;
 import software.amazon.awssdk.services.rds.model.StopDbInstanceAutomatedBackupsReplicationRequest;
 import software.amazon.awssdk.utils.StringUtils;
+import software.amazon.cloudformation.exceptions.CfnInvalidRequestException;
 import software.amazon.rds.common.handler.Commons;
 import software.amazon.rds.common.handler.Tagging;
 import software.amazon.rds.dbinstance.util.ResourceModelHelper;
@@ -444,6 +446,7 @@ public static ModifyDbInstanceRequest modifyDbInstanceRequestV12(
     public static ModifyDbInstanceRequest modifyDbInstanceRequest(
             final ResourceModel previousModel,
             final ResourceModel desiredModel,
+            final DBInstance physicalDBInstance,
             final Boolean isRollback
     ) {
         final ModifyDbInstanceRequest.Builder builder = ModifyDbInstanceRequest.builder()
@@ -495,16 +498,29 @@ public static ModifyDbInstanceRequest modifyDbInstanceRequest(
 
         if (BooleanUtils.isTrue(isRollback)) {
             if (isProvisionedIoStorage(desiredModel)) {
-                builder.allocatedStorage(max(getAllocatedStorage(previousModel), getAllocatedStorage(desiredModel)));
+                // 3-way max between previous model, desired model and current instance storage
+                // because you cannot shrink storage in RDS
+                final Integer allocatedStorage = max(getAllocatedStorage(previousModel), getAllocatedStorage(desiredModel));
+                builder.allocatedStorage(max(physicalDBInstance.allocatedStorage(), allocatedStorage));
                 builder.iops(desiredModel.getIops());
             }
         } else {
             builder.engineVersion(diff(previousModel.getEngineVersion(), desiredModel.getEngineVersion()));
+            final Integer allocatedStorageDiff = diff(getAllocatedStorage(previousModel), getAllocatedStorage(desiredModel));
+
+            // When you have an IOPS configurable storage type
+            // both parameters, allocatedStorage and iops MUST be specified in the modifyDBInstance call
             if (isProvisionedIoStorage(desiredModel)) {
-                builder.allocatedStorage(getAllocatedStorage(desiredModel));
+                if (allocatedStorageDiff != null) {
+                    // if user specifies allocated storage, then use it
+                    builder.allocatedStorage(allocatedStorageDiff);
+                } else {
+                    // if not, we should take max of physical and the template's in case their instance has scaled out
+                    builder.allocatedStorage(max(physicalDBInstance.allocatedStorage(), getAllocatedStorage(desiredModel)));
+                }
                 builder.iops(desiredModel.getIops());
             } else {
-                builder.allocatedStorage(diff(getAllocatedStorage(previousModel), getAllocatedStorage(desiredModel)));
+                builder.allocatedStorage(allocatedStorageDiff);
                 builder.iops(diff(previousModel.getIops(), desiredModel.getIops()));
             }
         }

aws-rds-dbinstance/src/main/java/software/amazon/rds/dbinstance/UpdateHandler.java

@@ -145,7 +145,10 @@ protected ProgressEvent<ResourceModel, CallbackContext> handleRequest(
                     progress.getCallbackContext().timestampOnce(RESOURCE_UPDATED_AT, Instant.now());
                     return versioned(proxy, rdsProxyClient, progress, null, ImmutableMap.of(
                             ApiVersion.V12, (pxy, pcl, prg, tgs) -> updateDbInstanceV12(pxy, request, pcl, prg),
-                            ApiVersion.DEFAULT, (pxy, pcl, prg, tgs) -> updateDbInstance(pxy, request, pcl, prg)
+                            ApiVersion.DEFAULT, (pxy, pcl, prg, tgs) -> {
+                            final DBInstance dbInstance = fetchDBInstance(rdsProxyClient.defaultClient(), progress.getResourceModel());
+                            return updateDbInstance(pxy, request, pcl, prg, dbInstance);
+                        }
                     )).then(p -> Events.checkFailedEvents(
                             rdsProxyClient.defaultClient(),
                             p.getResourceModel().getDBInstanceIdentifier(),