(aws-cdk-lib.aws_lambda): First lambda autoscaling example has incorrect import

[mpetito-envative]

Describe the issue

The first lambda autoscaling example has an incorrect import. Instead of importing from aws-cdk-lib/aws-autoscaling it should instead be importing from aws-cdk-lib/aws-applicationautoscaling.

The use of the Schedule class from the autoscaling lib generates a string value that will synth but produces incompatible cron expressions for the Schedule attribute since they will not be wrapped with cron(...).

Links

https://docs.aws.amazon.com/cdk/api/v2/docs/aws-cdk-lib.aws_lambda-readme.html#autoscaling

[ashishdhingra]

The first example at https://docs.aws.amazon.com/cdk/api/v2/docs/aws-cdk-lib.aws_lambda-readme.html#autoscaling, modified version below:

import * as cdk from 'aws-cdk-lib';
import * as autoscaling from 'aws-cdk-lib/aws-autoscaling';
import * as lambda from 'aws-cdk-lib/aws-lambda';

export class CdktestStackNew extends cdk.Stack {
  constructor(scope: cdk.App, id: string, props?: cdk.StackProps) {
    super(scope, id, props);

    const fn = new lambda.Function(this, 'MyLambda', {
      code: new lambda.InlineCode('exports.handler = async () => { console.log(\'hello world\'); };'),
      handler: 'index.handler',
      runtime: lambda.Runtime.NODEJS_LATEST,
    });

    const alias = fn.addAlias('prod');

    // Create AutoScaling target
    const as = alias.addAutoScaling({ maxCapacity: 50 });

    // Configure Target Tracking
    as.scaleOnUtilization({
      utilizationTarget: 0.5,
    });

    // Configure Scheduled Scaling
    as.scaleOnSchedule('ScaleUpInTheMorning', {
      schedule: autoscaling.Schedule.cron({ hour: '8', minute: '0' }),
      minCapacity: 20,
    });
  }
}

synthesizes to below CloudFormation template:

Resources:
  MyLambdaServiceRole4539ECB6:
    Type: AWS::IAM::Role
    Properties:
      AssumeRolePolicyDocument:
        Statement:
          - Action: sts:AssumeRole
            Effect: Allow
            Principal:
              Service: lambda.amazonaws.com
        Version: "2012-10-17"
      ManagedPolicyArns:
        - Fn::Join:
            - ""
            - - "arn:"
              - Ref: AWS::Partition
              - :iam::aws:policy/service-role/AWSLambdaBasicExecutionRole
    Metadata:
      aws:cdk:path: CdktestStackNew/MyLambda/ServiceRole/Resource
  MyLambdaCCE802FB:
    Type: AWS::Lambda::Function
    Properties:
      Code:
        ZipFile: exports.handler = async () => { console.log('hello world'); };
      Handler: index.handler
      Role:
        Fn::GetAtt:
          - MyLambdaServiceRole4539ECB6
          - Arn
      Runtime: nodejs18.x
    DependsOn:
      - MyLambdaServiceRole4539ECB6
    Metadata:
      aws:cdk:path: CdktestStackNew/MyLambda/Resource
  MyLambdaCurrentVersionE7A382CCe21d042dca0bfd565457befbbbeaab23:
    Type: AWS::Lambda::Version
    Properties:
      FunctionName:
        Ref: MyLambdaCCE802FB
    Metadata:
      aws:cdk:path: CdktestStackNew/MyLambda/CurrentVersion/Resource
  MyLambdaAliasprodE5E3E731:
    Type: AWS::Lambda::Alias
    Properties:
      FunctionName:
        Ref: MyLambdaCCE802FB
      FunctionVersion:
        Fn::GetAtt:
          - MyLambdaCurrentVersionE7A382CCe21d042dca0bfd565457befbbbeaab23
          - Version
      Name: prod
    Metadata:
      aws:cdk:path: CdktestStackNew/MyLambda/Aliasprod/Resource
  MyLambdaAliasprodAliasScalingTargetCBB1F7C5:
    Type: AWS::ApplicationAutoScaling::ScalableTarget
    Properties:
      MaxCapacity: 50
      MinCapacity: 1
      ResourceId:
        Fn::Join:
          - ""
          - - "function:"
            - Fn::Select:
                - 6
                - Fn::Split:
                    - ":"
                    - Ref: MyLambdaAliasprodE5E3E731
            - :prod
      RoleARN: arn:aws:iam::<<ACCOUNT-ID>>:role/aws-service-role/lambda.application-autoscaling.amazonaws.com/AWSServiceRoleForApplicationAutoScaling_LambdaConcurrency
      ScalableDimension: lambda:function:ProvisionedConcurrency
      ScheduledActions:
        - ScalableTargetAction:
            MinCapacity: 20
          Schedule: 0 8 * * *
          ScheduledActionName: ScaleUpInTheMorning
      ServiceNamespace: lambda
    Metadata:
      aws:cdk:path: CdktestStackNew/MyLambda/Aliasprod/AliasScaling/Target/Resource
  MyLambdaAliasprodAliasScalingTargetTracking364B3A43:
    Type: AWS::ApplicationAutoScaling::ScalingPolicy
    Properties:
      PolicyName: CdktestStackNewMyLambdaAliasprodAliasScalingTargetTrackingFF2E0ABB
      PolicyType: TargetTrackingScaling
      ScalingTargetId:
        Ref: MyLambdaAliasprodAliasScalingTargetCBB1F7C5
      TargetTrackingScalingPolicyConfiguration:
        PredefinedMetricSpecification:
          PredefinedMetricType: LambdaProvisionedConcurrencyUtilization
        TargetValue: 0.5
    Metadata:
      aws:cdk:path: CdktestStackNew/MyLambda/Aliasprod/AliasScaling/Target/Tracking/Resource
  CDKMetadata:
    Type: AWS::CDK::Metadata
    Properties:
      Analytics: v2:deflate64:H4sIAAAAAAAA/12MwWrDMBAFvyV3eeuEHnJNCz0XO+Ra1uut2ViWglZqKEL/XlTXOfQ0w/B4B9gfW2h3eNeGxrmxMkDuI9Js8K4f2eIyjAj5LTmK4p15/XQPv3DQv7bpyQpqDb9SjOACufOWa6ssBm83K4T1AVP0SmjFTZBfULkntDhYPsUYZEiRzVbOGCaO9eVfWXEOSLO4qV/f3r0V+t7Wj1CK6Vh9CsTFOD8yXPXpa3+EQwvPu6uKNCG5KAtDt/IHXl1cByABAAA=
    Metadata:
      aws:cdk:path: CdktestStackNew/CDKMetadata/Default
Parameters:
  BootstrapVersion:
    Type: AWS::SSM::Parameter::Value<String>
    Default: /cdk-bootstrap/hnb659fds/version
    Description: Version of the CDK Bootstrap resources in this environment, automatically retrieved from SSM Parameter Store. [cdk:skip]

It outputs AWS::ApplicationAutoScaling::ScalableTarget resource defining ScheduledAction having Schedule with cron(...) as one of the acceptable formats, instead of AWS::AutoScaling::ScheduledAction. AWS::AutoScaling::ScheduledAction is used for Amazon EC2 Auto Scaling scheduled action defining Recurrence string.

• Perhaps the 1st example at https://docs.aws.amazon.com/cdk/api/v2/docs/aws-cdk-lib.aws_lambda-readme.html#autoscaling should be updated to use aws-cdk-lib/aws-applicationautoscaling.
• Another example demonstrating use of aws-cdk-lib/aws-autoscaling for Amazon EC2 Auto Scaling scheduled action should be added.

[mpetito-envative]

I'm not sure I follow your conclusion. If you deploy the generated template you've shared, you will get a cloudformation error because Schedule: 0 8 * * * is invalid for an AWS::ApplicationAutoScaling::ScalableTarget. It does not conform to the acceptable expression syntax, which is Schedule: cron(fields).

Another example demonstrating use of aws-cdk-lib/aws-autoscaling for Amazon EC2 Auto Scaling scheduled action should be added.

The example referenced is in the aws_lambda module, so I'm not sure why an EC2 Auto Scaling example would be appropriate to show in the lambda docs. Unless I've missed something, EC2 Auto Scaling does not apply to lambda environments since lambda functions are not members of EC2 auto scaling groups.