AutoScalingGroup Constructor: Overloaded Constructor / Different Props

[NeilGGopal]

Describe the feature

Create overloaded constructor(s) for AutoScalingGroup with different properties. These alternate constructors can contain either launchTemplate or mixedInstancesPolicy while simultaneously removing all properties that must not be specified when either of these two props are passed into the original constructor.

Use Case

When migrating my CFN templates to CDK, it is difficult for me to debug my AutoScalingGroup CDK code because of the way ASGs are described in the CDK documentation and because of the way ASGs are defined in code. Building my templates takes a long time (even for a single package), and running into an error with launchTemplate, mixedInstancesPolicy and machineImage is frustrating.

Properties such as instanceType specify that the launchTemplate / mixedInstancesPolicy must not be specified. However, launchTemplate and mixedInstancesPolicy do not specify the other properties that break them in return.

To fix these issues, we can both add more detail to launchTemplate / mixedInstancesPolicy in the documentation and split the AutoScalingGroupProps interface into different interfaces to prevent this collision in the first place.

Proposed Solution

constructor(scope: Construct, id: string, props: ASGLaunchTemplateProps);

// ASGLaunchTemplateProps is the same as AutoScalingGroupProps minus the properties
// that state launchTemplate must not be specified
export interface ASGLaunchTemplateProps extends CommonASGLaunchTemplateProps {
readonly vpc: ec2.IVpc;
readonly launchTemplate?: ec2.ILaunchTemplate;
readonly init?: ec2.CloudFormationInit;
readonly initOptions?: ApplyCloudFormationInitOptions;
readonly requireImdsv2?: boolean;
}

// CommonASGLaunchTemplateProps is the same as CommonAutoScalingGroupProps minus the properties
// that state launchTemplate must not be specified
export interface CommonAutoScalingGroupProps {
readonly minCapacity?: number;
readonly maxCapacity?: number;
readonly desiredCapacity?: number;
readonly vpcSubnets?: ec2.SubnetSelection;
readonly notifications?: NotificationConfiguration[];
readonly allowAllOutbound?: boolean;
readonly ignoreUnmodifiedSizeProperties?: boolean;
readonly cooldown?: Duration;
readonly healthCheck?: HealthCheck;
readonly maxInstanceLifetime?: Duration;
readonly groupMetrics?: GroupMetrics[];
readonly signals?: Signals;
readonly updatePolicy?: UpdatePolicy;
readonly newInstancesProtectedFromScaleIn?: boolean;
readonly autoScalingGroupName?: string;
readonly terminationPolicies?: TerminationPolicy[];
readonly defaultInstanceWarmup?: Duration;
readonly ssmSessionPermissions?: boolean;
}

// Note: The original CommonAutoScalingGroupProps can also be modified to move the properties
// that state "launchTemplate must not be specified" to AutoScalingGroupProps

Other Information

No response

Acknowledgements

• I may be able to implement this feature request
• This feature might incur a breaking change

CDK version used

2.87.0

Environment details (OS name and version, etc.)

OSX / Using AL2_x86_64

[khushail]

Hi @NeilGGopal ,thanks for reaching out with this request.
As you mentioned about 2 workarounds -

1. updating the documentation => Yes this could be done provided what larifications are needed exactly and how should we improve the existing documentation which might help in easier debugging. Sharing a snippet of error code or insights could be helpful here.
2. Splitting the interface into multiple interfaces => this might not be a good idea as it contradicts with the design of cdk and we won't recommend doing so.

[github-actions]

This issue has not received a response in a while. If you want to keep this issue open, please leave a comment below and auto-close will be canceled.