feat(ec2): add versionDescription property for LaunchTemplate (aw…

…s#30837)

### Issue # (if applicable)

### Reason for this change
The change introduces the `versionDescription` property to the `LaunchTemplate`

### Description of changes
- Add the `versionDescription` property for `LaunchTemplateProps`, which was missing in the L2 construct.
- Add validation for character limit 

### Description of how you validated changes
I Added a unit test for launch template and added the `versionDescription` property in the integration tests.

### 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-testing/framework-integ/test/aws-ec2/test/integ.launch-template.js.snapshot/aws-cdk-ec2-lt-metadata-1.template.json

@@ -211,7 +211,8 @@
        }
       ]
      }
-    ]
+    ],
+    "VersionDescription": "test template v1"
    }
   },
   "sg2860DD91F": {

packages/@aws-cdk-testing/framework-integ/test/aws-ec2/test/integ.launch-template.ts

@@ -16,6 +16,7 @@ const sg1 = new ec2.SecurityGroup(stack, 'sg1', {
 });
 
 const lt = new ec2.LaunchTemplate(stack, 'LT', {
+  versionDescription: 'test template v1',
   httpEndpoint: true,
   httpProtocolIpv6: true,
   httpPutResponseHopLimit: 2,

packages/aws-cdk-lib/aws-ec2/README.md

@@ -2287,6 +2287,8 @@ const instanceProfile = new iam.InstanceProfile(this, 'InstanceProfile', {
 });
 
 const template = new ec2.LaunchTemplate(this, 'LaunchTemplate', {
+  launchTemplateName: 'MyTemplateV1',
+  versionDescription: 'This is my v1 template',
   machineImage: ec2.MachineImage.latestAmazonLinux2023(),
   securityGroup: new ec2.SecurityGroup(this, 'LaunchTemplateSG', {
     vpc: vpc,

packages/aws-cdk-lib/aws-ec2/lib/launch-template.ts

@@ -221,6 +221,17 @@ export interface LaunchTemplateProps {
    */
   readonly launchTemplateName?: string;
 
+  /**
+   * A description for the first version of the launch template.
+   *
+   * The version description must be maximum 255 characters long.
+   *
+   * @see http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-resource-ec2-launchtemplate.html#cfn-ec2-launchtemplate-versiondescription
+   *
+   * @default - No description
+   */
+  readonly versionDescription?: string;
+
   /**
    * Type of instance to launch.
    *
@@ -735,8 +746,13 @@ export class LaunchTemplate extends Resource implements ILaunchTemplate, iam.IGr
       ? [{ deviceIndex: 0, associatePublicIpAddress: props.associatePublicIpAddress, groups: securityGroupsToken }]
       : undefined;
 
+    if (props.versionDescription && !Token.isUnresolved(props.versionDescription) && props.versionDescription.length > 255) {
+      throw new Error(`versionDescription must be less than or equal to 255 characters, got ${props.versionDescription.length}`);
+    }
+
     const resource = new CfnLaunchTemplate(this, 'Resource', {
       launchTemplateName: props?.launchTemplateName,
+      versionDescription: props?.versionDescription,
       launchTemplateData: {
         blockDeviceMappings: props?.blockDevices !== undefined ? launchTemplateBlockDeviceMappings(this, props.blockDevices) : undefined,
         creditSpecification: props?.cpuCredits !== undefined ? {

packages/aws-cdk-lib/aws-ec2/test/launch-template.test.ts

@@ -147,6 +147,28 @@ describe('LaunchTemplate', () => {
     });
   });
 
+  test('Given versionDescription', () => {
+    // WHEN
+    new LaunchTemplate(stack, 'Template', {
+      versionDescription: 'test template',
+    });
+
+    // THEN
+    Template.fromStack(stack).hasResourceProperties('AWS::EC2::LaunchTemplate', {
+      VersionDescription: 'test template',
+    });
+  });
+
+  test('throw error when versionDescription is too long', () => {
+    const tooLongDescription = 'a'.repeat(256);
+    // WHEN / THEN
+    expect(() => {
+      new LaunchTemplate(stack, 'TemplateWithTooLongDescription', {
+        versionDescription: tooLongDescription,
+      });
+    }).toThrow('versionDescription must be less than or equal to 255 characters, got 256');
+  });
+
   test('Given instanceType', () => {
     // WHEN
     new LaunchTemplate(stack, 'Template', {