feat(sns): add fromTopicName api to import a sns topic via the topic name

packages/aws-cdk-lib/aws-sns/README.md

@@ -21,6 +21,26 @@ const topic = new sns.Topic(this, 'Topic', {
 
 Note that FIFO topics require a topic name to be provided. The required `.fifo` suffix will be automatically generated and added to the topic name if it is not explicitly provided.
 
+## Import
+
+Any SNS topics that has been created outside the stack can be imported into your CDK stack.
+
+Topics can be imported by their ARN via the `Topic.fromTopicArn()` API or using the topic name via the `StateMachine.fromTopicName()` API.
+
+```ts
+const topic = sns.Topic.fromTopicArn(
+  this,
+  'ViaArnImportedStateMachine',
+  'arn:aws:sns:us-east-1:123456789012:my-topic'
+);
+
+const topic = sns.Topic.fromTopicName(
+  this,
+  'ViaResourceNameImportedStateMachine',
+  'my-topic'
+);
+```
+
 ## Subscriptions
 
 Various subscriptions can be added to the topic by calling the

packages/aws-cdk-lib/aws-sns/lib/topic.ts

@@ -71,6 +71,21 @@ export class Topic extends TopicBase {
     return new Import(scope, id);
   }
 
+  /**
+   * Import an existing SNS topic provided the topic name
+   * @param scope The parent creating construct
+   * @param id The construct's name
+   * @param topicName The topic name (i.e. MyTopic)
+   */
+  public static fromTopicName(scope: Construct, id: string, topicName: string): ITopic {
+    const topicArn = Stack.of(scope).formatArn({
+      service: 'sns',
+      resource: topicName,
+      arnFormat: ArnFormat.COLON_RESOURCE_NAME,
+    });
+    return this.fromTopicArn(scope, id, topicArn);
+  }
+
   public readonly topicArn: string;
   public readonly topicName: string;
   public readonly fifo: boolean;

packages/aws-cdk-lib/aws-sns/test/sns.test.ts

@@ -349,6 +349,33 @@ describe('Topic', () => {
     expect(imported.fifo).toEqual(true);
   });
 
+  test('fromTopicName', () => {
+    // GIVEN
+    const stack2 = new cdk.Stack();
+
+    // WHEN
+    const imported = sns.Topic.fromTopicName(stack2, 'Imported', 'my_corporate_topic');
+
+    // THEN
+    expect(imported.topicName).toEqual('my_corporate_topic');
+    expect(imported.topicArn).toEqual('arn:aws:sns:*:123456789012:my_corporate_topic');
+    expect(imported.fifo).toEqual(false);
+
+  });
+
+  test('fromTopicName fifo', () => {
+    // GIVEN
+    const stack = new cdk.Stack();
+
+    // WHEN
+    const imported = sns.Topic.fromTopicName(stack, 'Imported', 'mytopic.fifo');
+
+    // THEN
+    expect(imported.topicName).toEqual('mytopic.fifo');
+    expect(imported.topicArn).toEqual('arn:aws:sns:*:123456789012:mytopic.fifo');
+    expect(imported.fifo).toEqual(true);
+  });
+
   test('test metrics', () => {
     // GIVEN
     const stack = new cdk.Stack();