From da2ec75f6bc8f2e28b07cdf1307b22c83bb652d5 Mon Sep 17 00:00:00 2001
From: soso <sonishimura15@gmail.com>
Date: Mon, 29 Jul 2024 11:44:46 +0900
Subject: [PATCH] feat(sns): add validation of `displayName` for topic (#30770)

### Issue # (if applicable)

--

### Reason for this change

Display errors before deploying

### Description of changes

- Implement length check for displayName (maximum 100 characters long)
    - [AWS::SNS::Topic](https://docs.aws.amazon.com/ja_jp/AWSCloudFormation/latest/UserGuide/aws-resource-sns-topic.html#cfn-sns-topic-displayname)

### Description of how you validated changes

I added unit tests and confirmed all tests passed.

### 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*
---
 packages/aws-cdk-lib/aws-sns/lib/topic.ts     |  7 +++++++
 packages/aws-cdk-lib/aws-sns/test/sns.test.ts | 10 ++++++++++
 2 files changed, 17 insertions(+)

diff --git a/packages/aws-cdk-lib/aws-sns/lib/topic.ts b/packages/aws-cdk-lib/aws-sns/lib/topic.ts
index a57569060be8d..f78b32bf8cfe3 100644
--- a/packages/aws-cdk-lib/aws-sns/lib/topic.ts
+++ b/packages/aws-cdk-lib/aws-sns/lib/topic.ts
@@ -12,6 +12,9 @@ export interface TopicProps {
   /**
    * A developer-defined string that can be used to identify this SNS topic.
    *
+   * The display name must be maximum 100 characters long, including hyphens (-),
+   * underscores (_), spaces, and tabs.
+   *
    * @default None
    */
   readonly displayName?: string;
@@ -296,6 +299,10 @@ export class Topic extends TopicBase {
       throw new Error(`signatureVersion must be "1" or "2", received: "${props.signatureVersion}"`);
     }
 
+    if (props.displayName && !Token.isUnresolved(props.displayName) && props.displayName.length > 100) {
+      throw new Error(`displayName must be less than or equal to 100 characters, got ${props.displayName.length}`);
+    }
+
     const resource = new CfnTopic(this, 'Resource', {
       archivePolicy: props.messageRetentionPeriodInDays ? {
         MessageRetentionPeriod: props.messageRetentionPeriodInDays,
diff --git a/packages/aws-cdk-lib/aws-sns/test/sns.test.ts b/packages/aws-cdk-lib/aws-sns/test/sns.test.ts
index fc1f1cd4c2846..6c8f04fb096b6 100644
--- a/packages/aws-cdk-lib/aws-sns/test/sns.test.ts
+++ b/packages/aws-cdk-lib/aws-sns/test/sns.test.ts
@@ -176,6 +176,16 @@ describe('Topic', () => {
         signatureVersion: '3',
       })).toThrow(/signatureVersion must be "1" or "2", received: "3"/);
     });
+
+    test('throw error when displayName is too long', () => {
+      const stack = new cdk.Stack();
+
+      expect(() => {
+        new sns.Topic(stack, 'MyTopic', {
+          displayName: 'a'.repeat(101),
+        });
+      }).toThrow('displayName must be less than or equal to 100 characters, got 101');
+    });
   });
 
   test('can add a policy to the topic', () => {