feat(cloudfront): distribution ARN property (#32531)

### Issue # (if applicable)

Closes #32530

### Reason for this change

Give the user access to a distribution's ARN via the existing `distributionId` value.

### Description of changes

Implemented by proxying the existing `formatDistributionArn` function via a getter method.

### Description of how you validated changes

Unit tests were added for both created and imported distributions.

Additionally, missing coverage for `Distribution.fromDistributionAttributes` was added, by copying the existing unit test for `CloudFrontWebDistribution.fromDistributionAttributes`.

### Checklist
- [x] My code adheres to the [CONTRIBUTING GUIDE](https://github.com/aws/aws-cdk/blob/main/CONTRIBUTING.md) and [DESIGN GUIDELINES](https://github.com/aws/aws-cdk/blob/main/docs/DESIGN_GUIDELINES.md)

----

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

Author: nmussy

packages/aws-cdk-lib/aws-cloudfront/lib/distribution.ts

@@ -44,6 +44,13 @@ export interface IDistribution extends IResource {
    */
   readonly distributionId: string;
 
+  /**
+   * The distribution ARN for this distribution.
+   *
+   * @attribute
+   */
+  readonly distributionArn: string;
+
   /**
    * Adds an IAM policy statement associated with this distribution to an IAM
    * principal's policy.
@@ -291,6 +298,9 @@ export class Distribution extends Resource implements IDistribution {
         this.distributionId = attrs.distributionId;
       }
 
+      public get distributionArn(): string {
+        return formatDistributionArn(this);
+      }
       public grant(grantee: iam.IGrantable, ...actions: string[]): iam.Grant {
         return iam.Grant.addToPrincipal({ grantee, actions, resourceArns: [formatDistributionArn(this)] });
       }
@@ -389,6 +399,10 @@ export class Distribution extends Resource implements IDistribution {
     }
   }
 
+  public get distributionArn(): string {
+    return formatDistributionArn(this);
+  }
+
   /**
    * Return the given named metric for this Distribution
    */

packages/aws-cdk-lib/aws-cloudfront/lib/web-distribution.ts

@@ -761,6 +761,9 @@ export class CloudFrontWebDistribution extends cdk.Resource implements IDistribu
         this.distributionId = attrs.distributionId;
       }
 
+      public get distributionArn(): string {
+        return formatDistributionArn(this);
+      }
       public grant(grantee: iam.IGrantable, ...actions: string[]): iam.Grant {
         return iam.Grant.addToPrincipal({ grantee, actions, resourceArns: [formatDistributionArn(this)] });
       }
@@ -992,6 +995,10 @@ export class CloudFrontWebDistribution extends cdk.Resource implements IDistribu
     this.distributionId = distribution.ref;
   }
 
+  public get distributionArn(): string {
+    return formatDistributionArn(this);
+  }
+
   /**
    * Adds an IAM policy statement associated with this distribution to an IAM
    * principal's policy.

packages/aws-cdk-lib/aws-cloudfront/test/distribution.test.ts

@@ -6,7 +6,7 @@ import * as iam from '../../aws-iam';
 import * as kinesis from '../../aws-kinesis';
 import * as lambda from '../../aws-lambda';
 import * as s3 from '../../aws-s3';
-import { App, Duration, Stack } from '../../core';
+import { App, Aws, Duration, Stack } from '../../core';
 import {
   CfnDistribution,
   Distribution,
@@ -36,7 +36,7 @@ beforeEach(() => {
 
 test('minimal example renders correctly', () => {
   const origin = defaultOrigin();
-  new Distribution(stack, 'MyDist', { defaultBehavior: { origin } });
+  const dist = new Distribution(stack, 'MyDist', { defaultBehavior: { origin } });
 
   Template.fromStack(stack).hasResourceProperties('AWS::CloudFront::Distribution', {
     DistributionConfig: {
@@ -58,6 +58,19 @@ test('minimal example renders correctly', () => {
       }],
     },
   });
+
+  expect(dist.distributionArn).toEqual(`arn:${Aws.PARTITION}:cloudfront::1234:distribution/${dist.distributionId}`);
+});
+
+test('existing distributions can be imported', () => {
+  const dist = Distribution.fromDistributionAttributes(stack, 'ImportedDist', {
+    domainName: 'd111111abcdef8.cloudfront.net',
+    distributionId: '012345ABCDEF',
+  });
+
+  expect(dist.distributionDomainName).toEqual('d111111abcdef8.cloudfront.net');
+  expect(dist.distributionId).toEqual('012345ABCDEF');
+  expect(dist.distributionArn).toEqual(`arn:${Aws.PARTITION}:cloudfront::1234:distribution/012345ABCDEF`);
 });
 
 test('exhaustive example of props renders correctly and SSL method sni-only', () => {

packages/aws-cdk-lib/aws-cloudfront/test/web-distribution.test.ts

@@ -133,7 +133,7 @@ describe('web distribution', () => {
     const stack = new cdk.Stack();
     const sourceBucket = new s3.Bucket(stack, 'Bucket');
 
-    new CloudFrontWebDistribution(stack, 'AnAmazingWebsiteProbably', {
+    const dist = new CloudFrontWebDistribution(stack, 'AnAmazingWebsiteProbably', {
       originConfigs: [
         {
           s3OriginSource: {
@@ -204,6 +204,7 @@ describe('web distribution', () => {
       },
     });
 
+    expect(dist.distributionArn).toEqual(`arn:${cdk.Aws.PARTITION}:cloudfront::${cdk.Aws.ACCOUNT_ID}:distribution/${dist.distributionId}`);
   });
 
   test('can disable distribution', () => {
@@ -1722,6 +1723,7 @@ added the ellipsis so a user would know there was more to r...`,
 
     expect(dist.distributionDomainName).toEqual('d111111abcdef8.cloudfront.net');
     expect(dist.distributionId).toEqual('012345ABCDEF');
+    expect(dist.distributionArn).toEqual(`arn:${cdk.Aws.PARTITION}:cloudfront::${cdk.Aws.ACCOUNT_ID}:distribution/012345ABCDEF`);
 
   });
 });