feat(efs): add support for backup policy (#10524)

Add support for setting `BackupPolicy` to the `FileSystem` L2 construct. [Reference](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-resource-efs-filesystem.html#cfn-efs-filesystem-backuppolicy)

closes #10414 

----

*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

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

@@ -76,7 +76,8 @@ const fileSystem = new efs.FileSystem(this, 'MyEfsFileSystem', {
   encrypted: true,
   lifecyclePolicy: efs.LifecyclePolicy.AFTER_14_DAYS,
   performanceMode: efs.PerformanceMode.GENERAL_PURPOSE,
-  throughputMode: efs.ThroughputMode.BURSTING
+  throughputMode: efs.ThroughputMode.BURSTING,
+  enableAutomaticBackups: true
 });
 
 const inst = new Instance(this, 'inst', {

packages/@aws-cdk/aws-efs/lib/efs-file-system.ts

@@ -171,6 +171,13 @@ export interface FileSystemProps {
    * @default RemovalPolicy.RETAIN
    */
   readonly removalPolicy?: RemovalPolicy;
+
+  /**
+   * Whether to enable automatic backups for the file system.
+   *
+   * @default false
+   */
+  readonly enableAutomaticBackups?: boolean;
 }
 
 /**
@@ -252,6 +259,7 @@ export class FileSystem extends Resource implements IFileSystem {
       performanceMode: props.performanceMode,
       throughputMode: props.throughputMode,
       provisionedThroughputInMibps: props.provisionedThroughputPerSecond?.toMebibytes(),
+      backupPolicy: props.enableAutomaticBackups ? { status: 'ENABLED' } : undefined,
     });
     filesystem.applyRemovalPolicy(props.removalPolicy);
 

packages/@aws-cdk/aws-efs/test/efs-file-system.test.ts

@@ -7,7 +7,7 @@ import { FileSystem, LifecyclePolicy, PerformanceMode, ThroughputMode } from '..
 let stack = new Stack();
 let vpc = new ec2.Vpc(stack, 'VPC');
 
-beforeEach( () => {
+beforeEach(() => {
   stack = new Stack();
   vpc = new ec2.Vpc(stack, 'VPC');
 });
@@ -216,11 +216,24 @@ test('auto-named if none provided', () => {
 });
 
 test('removalPolicy is DESTROY', () => {
+  // WHEN
   new FileSystem(stack, 'EfsFileSystem', { vpc, removalPolicy: RemovalPolicy.DESTROY });
 
+  // THEN
   expectCDK(stack).to(haveResource('AWS::EFS::FileSystem', {
     DeletionPolicy: 'Delete',
     UpdateReplacePolicy: 'Delete',
   }, ResourcePart.CompleteDefinition));
+});
+
+test('can specify backup policy', () => {
+  // WHEN
+  new FileSystem(stack, 'EfsFileSystem', { vpc, enableAutomaticBackups: true });
 
+  // THEN
+  expectCDK(stack).to(haveResource('AWS::EFS::FileSystem', {
+    BackupPolicy: {
+      Status: 'ENABLED',
+    },
+  }));
 });