feat(s3-deployment): add additional sources with addSource (aws#23321)

PR aws#22857 is introducing a use case where we need to be able to add additional sources after the `BucketDeployment` resource is created.

This PR adds an `addSource` method and changes all the sources evaluation within the construct to be lazy.


----

### All Submissions:

* [ ] Have you followed the guidelines in our [Contributing guide?](https://github.com/aws/aws-cdk/blob/main/CONTRIBUTING.md)

### Adding new Construct Runtime Dependencies:

* [ ] This PR adds new construct runtime dependencies following the process described [here](https://github.com/aws/aws-cdk/blob/main/CONTRIBUTING.md/#adding-construct-runtime-dependencies)

### New Features

* [ ] Have you added the new feature to an [integration test](https://github.com/aws/aws-cdk/blob/main/INTEGRATION_TESTS.md)?
	* [ ] Did you use `yarn integ` to deploy the infrastructure and generate the snapshot (i.e. `yarn integ` without `--dry-run`)?

*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-s3-deployment/README.md

@@ -61,6 +61,20 @@ new ConstructThatReadsFromTheBucket(this, 'Consumer', {
 });
 ```
 
+It is also possible to add additional sources using the `addSource` method.
+
+```ts
+declare const websiteBucket: s3.IBucket;
+
+const deployment = new s3deploy.BucketDeployment(this, 'DeployWebsite', {
+  sources: [s3deploy.Source.asset('./website-dist')],
+  destinationBucket: websiteBucket,
+  destinationKeyPrefix: 'web/static', // optional prefix in destination bucket
+});
+
+deployment.addSource(s3deploy.Source.asset('./another-asset'));
+```
+
 ## Supported sources
 
 The following source types are supported for bucket deployments:

packages/@aws-cdk/aws-s3-deployment/lib/bucket-deployment.ts

@@ -253,6 +253,8 @@ export class BucketDeployment extends Construct {
   private readonly cr: cdk.CustomResource;
   private _deployedBucket?: s3.IBucket;
   private requestDestinationArn: boolean = false;
+  private readonly sources: SourceConfig[];
+  private readonly handlerRole: iam.IRole;
 
   constructor(scope: Construct, id: string, props: BucketDeploymentProps) {
     super(scope, id);
@@ -327,8 +329,9 @@ export class BucketDeployment extends Construct {
 
     const handlerRole = handler.role;
     if (!handlerRole) { throw new Error('lambda.SingletonFunction should have created a Role'); }
+    this.handlerRole = handlerRole;
 
-    const sources: SourceConfig[] = props.sources.map((source: ISource) => source.bind(this, { handlerRole }));
+    this.sources = props.sources.map((source: ISource) => source.bind(this, { handlerRole: this.handlerRole }));
 
     props.destinationBucket.grantReadWrite(handler);
     if (props.accessControl) {
@@ -342,24 +345,35 @@ export class BucketDeployment extends Construct {
       }));
     }
 
-    // to avoid redundant stack updates, only include "SourceMarkers" if one of
-    // the sources actually has markers.
-    const hasMarkers = sources.some(source => source.markers);
-
     // Markers are not replaced if zip sources are not extracted, so throw an error
     // if extraction is not wanted and sources have markers.
-    if (hasMarkers && props.extract == false) {
-      throw new Error('Some sources are incompatible with extract=false; sources with deploy-time values (such as \'snsTopic.topicArn\') must be extracted.');
-    }
+    const _this = this;
+    this.node.addValidation({
+      validate(): string[] {
+        if (_this.sources.some(source => source.markers) && props.extract == false) {
+          return ['Some sources are incompatible with extract=false; sources with deploy-time values (such as \'snsTopic.topicArn\') must be extracted.'];
+        }
+        return [];
+      },
+    });
 
     const crUniqueId = `CustomResource${this.renderUniqueId(props.memoryLimit, props.ephemeralStorageSize, props.vpc)}`;
     this.cr = new cdk.CustomResource(this, crUniqueId, {
       serviceToken: handler.functionArn,
       resourceType: 'Custom::CDKBucketDeployment',
       properties: {
-        SourceBucketNames: sources.map(source => source.bucket.bucketName),
-        SourceObjectKeys: sources.map(source => source.zipObjectKey),
-        SourceMarkers: hasMarkers ? sources.map(source => source.markers ?? {}) : undefined,
+        SourceBucketNames: cdk.Lazy.list({ produce: () => this.sources.map(source => source.bucket.bucketName) }),
+        SourceObjectKeys: cdk.Lazy.list({ produce: () => this.sources.map(source => source.zipObjectKey) }),
+        SourceMarkers: cdk.Lazy.any({
+          produce: () => {
+            return this.sources.reduce((acc, source) => {
+              if (source.markers) {
+                acc.push(source.markers);
+              }
+              return acc;
+            }, [] as Array<Record<string, any>>);
+          },
+        }, { omitEmptyArray: true }),
         DestinationBucketName: props.destinationBucket.bucketName,
         DestinationBucketKeyPrefix: props.destinationKeyPrefix,
         RetainOnDelete: props.retainOnDelete,
@@ -465,6 +479,22 @@ export class BucketDeployment extends Construct {
     return objectKeys;
   }
 
+  /**
+   * Add an additional source to the bucket deployment
+   *
+   * @example
+   * declare const websiteBucket: s3.IBucket;
+   * const deployment = new s3deploy.BucketDeployment(this, 'Deployment', {
+   *   sources: [s3deploy.Source.asset('./website-dist')],
+   *   destinationBucket: websiteBucket,
+   * });
+   *
+   * deployment.addSource(s3deploy.Source.asset('./another-asset'));
+   */
+  public addSource(source: ISource): void {
+    this.sources.push(source.bind(this, { handlerRole: this.handlerRole }));
+  }
+
   private renderUniqueId(memoryLimit?: number, ephemeralStorageSize?: cdk.Size, vpc?: ec2.IVpc) {
     let uuid = '';
 

packages/@aws-cdk/aws-s3-deployment/test/bucket-deployment.test.ts

@@ -997,14 +997,15 @@ test('given a source with markers and extract is false, BucketDeployment throws
       },
     },
   });
+  new s3deploy.BucketDeployment(stack, 'Deploy', {
+    sources: [file],
+    destinationBucket: bucket,
+    extract: false,
+  });
 
   // THEN
   expect(() => {
-    new s3deploy.BucketDeployment(stack, 'Deploy', {
-      sources: [file],
-      destinationBucket: bucket,
-      extract: false,
-    });
+    Template.fromStack(stack);
   }).toThrow('Some sources are incompatible with extract=false; sources with deploy-time values (such as \'snsTopic.topicArn\') must be extracted.');
 });
 
@@ -1360,6 +1361,29 @@ test('Source.jsonData() can be used to create a file with a JSON object', () =>
   });
 });
 
+test('can add sources with addSource', () => {
+  const app = new cdk.App();
+  const stack = new cdk.Stack(app, 'Test');
+  const bucket = new s3.Bucket(stack, 'Bucket');
+  const deployment = new s3deploy.BucketDeployment(stack, 'Deploy', {
+    sources: [s3deploy.Source.data('my/path.txt', 'helloWorld')],
+    destinationBucket: bucket,
+  });
+  deployment.addSource(s3deploy.Source.data('my/other/path.txt', 'hello world'));
+
+  const result = app.synth();
+  const content = readDataFile(result, 'my/path.txt');
+  const content2 = readDataFile(result, 'my/other/path.txt');
+  expect(content).toStrictEqual('helloWorld');
+  expect(content2).toStrictEqual('hello world');
+  Template.fromStack(stack).hasResourceProperties('Custom::CDKBucketDeployment', {
+    SourceMarkers: [
+      {},
+      {},
+    ],
+  });
+});
+
 
 function readDataFile(casm: cxapi.CloudAssembly, relativePath: string): string {
   const assetDirs = readdirSync(casm.directory).filter(f => f.startsWith('asset.'));

packages/@aws-cdk/aws-s3-deployment/test/integ.bucket-deployment-data.ts

@@ -10,13 +10,14 @@ const file1 = Source.data('file1.txt', 'boom');
 const file2 = Source.data('path/to/file2.txt', `bam! ${bucket.bucketName}`);
 const file3 = Source.jsonData('my/config.json', { website_url: bucket.bucketWebsiteUrl });
 
-new BucketDeployment(stack, 'DeployMeHere', {
+const deployment = new BucketDeployment(stack, 'DeployMeHere', {
   destinationBucket: bucket,
-  sources: [file1, file2, file3],
+  sources: [file1, file2],
   destinationKeyPrefix: 'deploy/here/',
   retainOnDelete: false, // default is true, which will block the integration test cleanup
 });
+deployment.addSource(file3);
 
 new CfnOutput(stack, 'BucketName', { value: bucket.bucketName });
 
-app.synth();
+app.synth();