(aws-elasticache-alpha): ServerlessCache deployment fails when serverlessCacheName is not specified

[mazyu36]

Describe the bug

When deploying a ServerlessCache without explicitly specifying serverlessCacheName, the auto-generated name using Names.uniqueId() can exceed the AWS ElastiCache 40 character limit, causing deployment failure.

Current implementation in serverless-cache.ts:

this.serverlessCacheName = props.serverlessCacheName ?? Lazy.string({ produce: () => Names.uniqueId(this) });

Names.uniqueId() has no length limit, so when the stack name or construct path is long, the generated name exceeds 40 characters.

Regression Issue

• Select this option if this issue appears to be a regression.

Last Known Working CDK Library Version

No response

Expected Behavior

ServerlessCache should deploy successfully with an auto-generated name that respects the AWS 40 character limit. It should use Names.uniqueResourceName() with maxLength like other CDK constructs.

Current Behavior

Deployment fails with the following error:

Resource handler returned message: "Serverless Cache Name cannot be longer than 40 characters. 
(Service: ElastiCache, Status Code: 400, Request ID: xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx)" 
(RequestToken: xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx, HandlerErrorCode: InvalidRequest)

Reproduction Steps

import { App, Stack } from 'aws-cdk-lib';
import { Vpc } from 'aws-cdk-lib/aws-ec2';
import { ServerlessCache, CacheEngine } from '@aws-cdk/aws-elasticache-alpha';

const app = new App();
// Use a long stack name to reproduce the issue
const stack = new Stack(app, 'my-application-serverless-cache-stack');

const vpc = new Vpc(stack, 'VPC');

// Do not specify serverlessCacheName - rely on auto-generation
new ServerlessCache(stack, 'MyServerlessCache', {
  vpc,
  engine: CacheEngine.MEMCACHED_1_6,
});

Possible Solution

Replace Names.uniqueId() with Names.uniqueResourceName() and specify maxLength: 40:

this.serverlessCacheName = props.serverlessCacheName ?? Lazy.string({
  produce: () => Names.uniqueResourceName(this, { maxLength: 40 }),
});

This is consistent with other CDK constructs:

• aws-appconfig: Names.uniqueResourceName(this, { maxLength: 64 })
• aws-cloudfront: Names.uniqueResourceName(this, { maxLength: 64 })
• aws-rds/proxy: Names.uniqueResourceName(this, { maxLength: 60 })

Note: user-group.ts has the same issue (also uses Names.uniqueId()).

Additional Information/Context

No response

AWS CDK Library version (aws-cdk-lib)

v2.233.0

AWS CDK CLI version

2.1033.0

Node.js Version

v22.14.0

OS

OSX

Language

TypeScript

Language Version

No response

Other information

No response

[pahud]

Hi @mazyu36,

Thank you for reporting this issue with a clear reproduction case and proposed solution!

From my analysis, the current implementation uses Names.uniqueId() which has no length limit, causing deployment failures when the generated name exceeds ElastiCache's 40 character limit.

Your proposed fix is correct and follows the established CDK pattern:

this.serverlessCacheName = props.serverlessCacheName ?? Lazy.string({
  produce: () => Names.uniqueResourceName(this, { maxLength: 40 }),
});

This is consistent with how other CDK constructs handle name length limits (appconfig, cloudfront, rds/proxy).

Good catch on user-group.ts having the same issue - that should be fixed as well.

Since this is a straightforward fix, would you be interested in submitting a PR? We'd welcome your contribution! 🙏