feat(rds): database instance - auto scale allocated storage

packages/@aws-cdk/aws-rds/README.md

@@ -58,6 +58,21 @@ const instance = new DatabaseInstance(stack, 'Instance', {
 ```
 By default, the master password will be generated and stored in AWS Secrets Manager.
 
+To use the storage auto scaling option of RDS you can specify the maximum allocated storage.
+This is the upper limit to which RDS can automatically scale the storage. More info can be found
+[here](https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/USER_PIOPS.StorageTypes.html#USER_PIOPS.Autoscaling)
+Example for max storage configuration:
+
+```ts
+const instance = new DatabaseInstance(stack, 'Instance', {
+    engine: rds.DatabaseInstanceEngine.ORACLE_SE1,
+    instanceClass: ec2.InstanceType.of(ec2.InstanceClass.BURSTABLE2, ec2.InstanceSize.SMALL),
+    masterUsername: 'syscdk',
+    vpc,
+    maxAllocatedStorage: 200
+});
+```
+
 Use `DatabaseInstanceFromSnapshot` and `DatabaseInstanceReadReplica` to create an instance from snapshot or
 a source database respectively:
 
@@ -76,6 +91,7 @@ new DatabaseInstanceReadReplica(stack, 'ReadReplica', {
     vpc
 });
 ```
+
 Creating a "production" Oracle database instance with option and parameter groups:
 
 [example of setting up a production oracle instance](test/integ.instance.lit.ts)

packages/@aws-cdk/aws-rds/lib/instance.ts

@@ -478,6 +478,13 @@ export interface DatabaseInstanceNewProps {
    * @default RemovalPolicy.Retain
    */
   readonly removalPolicy?: RemovalPolicy
+
+  /**
+   * Upper limit to which RDS can scale the storage in GiB(Gibibyte).
+   * @see https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/USER_PIOPS.StorageTypes.html#USER_PIOPS.Autoscaling
+   * @default - No autoscaling of RDS instance
+   */
+  readonly maxAllocatedStorage?: number;
 }
 
 /**
@@ -567,7 +574,8 @@ abstract class DatabaseInstanceNew extends DatabaseInstanceBase implements IData
       processorFeatures: props.processorFeatures && renderProcessorFeatures(props.processorFeatures),
       publiclyAccessible: props.vpcPlacement && props.vpcPlacement.subnetType === ec2.SubnetType.PUBLIC,
       storageType,
-      vpcSecurityGroups: securityGroups.map(s => s.securityGroupId)
+      vpcSecurityGroups: securityGroups.map(s => s.securityGroupId),
+      maxAllocatedStorage: props.maxAllocatedStorage
     };
   }
 

packages/@aws-cdk/aws-rds/test/test.instance.ts

@@ -716,6 +716,52 @@ export = {
       }), /timezone property can be configured only for Microsoft SQL Server/);
     });
 
+    test.done();
+  },
+
+  'create an instance from snapshot with maximum allocated storage'(test: Test) {
+    // GIVEN
+    const stack = new cdk.Stack();
+    const vpc = new ec2.Vpc(stack, 'VPC');
+
+    // WHEN
+    new rds.DatabaseInstanceFromSnapshot(stack, 'Instance', {
+      snapshotIdentifier: 'my-snapshot',
+      engine: rds.DatabaseInstanceEngine.POSTGRES,
+      instanceClass: ec2.InstanceType.of(ec2.InstanceClass.BURSTABLE2, ec2.InstanceSize.LARGE),
+      vpc,
+      maxAllocatedStorage: 200
+    });
+
+    expect(stack).to(haveResource('AWS::RDS::DBInstance', {
+      DBSnapshotIdentifier: 'my-snapshot',
+      MaxAllocatedStorage: 200
+    }));
+
+    test.done();
+  },
+
+  'create a DB instance with maximum allocated storage'(test: Test) {
+    // GIVEN
+    const stack = new cdk.Stack();
+    const vpc = new ec2.Vpc(stack, 'VPC');
+
+    // WHEN
+    new rds.DatabaseInstance(stack, 'Instance', {
+      engine: rds.DatabaseInstanceEngine.MYSQL,
+      instanceClass: ec2.InstanceType.of(ec2.InstanceClass.BURSTABLE2, ec2.InstanceSize.SMALL),
+      masterUsername: 'admin',
+      vpc,
+      backupRetention: cdk.Duration.seconds(0),
+      maxAllocatedStorage: 250
+    });
+
+    // THEN
+    expect(stack).to(haveResource('AWS::RDS::DBInstance', {
+      BackupRetentionPeriod: 0,
+      MaxAllocatedStorage: 250
+    }));
+
     test.done();
   }
 };