aws/aws-cdk

elasticache-alpha: dailyBackupTime field uses misleading Schedule type

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#36,981 opened on Feb 12, 2026

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Description

Describe the bug

The alpha elasticache module uses events.Schedule for dailyBackupTime. The expected elasticache type in the Cfn is just a time of day string HH:MM, but schedule is essentially a full cron interface leading to user potentially configuring a bunch of things that are irrelevant to the field.

https://github.com/aws/aws-cdk/blob/67f09c04ad860ff25494e1e76071c304adcf39b4/packages/%40aws-cdk/aws-elasticache-alpha/lib/serverless-cache.ts#L84

Proposal: Create a new helper type to specify time of day or revert back to expect a string on this field with validation in the construct that it matches expected string format.

Regression Issue

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

Last Known Working CDK Library Version

No response

Expected Behavior

Not to use Schedule type for this field

Current Behavior

uses overly broad Schedule type

Reproduction Steps

n/a

Possible Solution

No response

Additional Information/Context

No response

AWS CDK Library version (aws-cdk-lib)

n/a

AWS CDK CLI version

n/a

Node.js Version

n/a

OS

n/a

Language

TypeScript

Language Version

No response

Other information

No response

Contributor guide

Research direction
Examine the Schedule type from the events module, understand its interface, and propose or create a new TimeOfDay type that accepts HH:MM string format with validation. Then replace the dailyBackupTime field type from Schedule to the new TimeOfDay type in the serverless cache.ts file.
Tech stack
typescript
Domain
backendapi
Issue type
Bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
Half day
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
TypeScriptAWS CDK
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
45