AWS CustomResource example - Autoscaling group suspend/resume processes

asg-suspend.yaml

AWSTemplateFormatVersion: 2010-09-09
Description: 'Custom resource example - ASG suspend/resume'

Parameters:
  Input:
    Type: String
    Description: Make ASG
    Default: true
    AllowedValues: [true, false]

Conditions:
  Enabled: !Equals [!Ref Input, true]

Resources:
  Asg:
    Type: AWS::AutoScaling::AutoScalingGroup
    Condition: Enabled
    Properties:
      AvailabilityZones:
        Fn::GetAZs:
          Ref: "AWS::Region"
      LaunchConfigurationName: !Ref LC
      MaxSize: 0
      MinSize: 0

  LC:
    Type: AWS::AutoScaling::LaunchConfiguration
    Properties:
      # Update to suit
      ImageId: "ami-db704cb8"
      InstanceType: "t2.micro"

  AsgProcessModificationRole:
    Type: AWS::IAM::Role
    Properties:
      AssumeRolePolicyDocument:
        Version: 2012-10-17
        Statement:
        - Action: ['sts:AssumeRole']
          Effect: Allow
          Principal:
            Service: [lambda.amazonaws.com]
      Policies:
      - PolicyName: AsgProcessModification
        PolicyDocument:
          Version: 2012-10-17
          Statement:
          - Effect: Allow
            Action:
            - 'autoscaling:ResumeProcesses'
            - 'autoscaling:SuspendProcesses'
            # http://docs.aws.amazon.com/autoscaling/latest/userguide/IAM.html#AutoScaling_ARN_Format
            Resource: '*'
          - Effect: Allow
            Action:
            - logs:CreateLogGroup,
            - logs:CreateLogStream,
            - logs:PutLogEvents
            Resource: 'arn:aws:logs:*:*:*'

  AsgProcessModifierFunction:
    Type: AWS::Lambda::Function
    Properties:
      Description: 'Modifies ASG processes during CF stack creation'
      Code:
        ZipFile: |
          import cfnresponse
          import boto3

          def handler(event, context):
            print 'event: ', event
            print 'context: ', context
            client = boto3.client('autoscaling')
            props = event['ResourceProperties']
            if props['Action'] == 'SuspendProcesses':
              response = client.suspend_processes(AutoScalingGroupName=props['AutoScalingGroupName'], ScalingProcesses=props['ScalingProcesses'])
            elif props['Action'] == 'ResumeProcesses':
              response = client.resume_processes(AutoScalingGroupName=props['AutoScalingGroupName'], ScalingProcesses=props['ScalingProcesses'])
            cfnresponse.send(event, context, cfnresponse.SUCCESS, {}, "CustomResourcePhysicalID")
      Handler: index.handler
      Role: !GetAtt AsgProcessModificationRole.Arn
      Runtime: 'python2.7'

  ModifyAsg:
    Type: AWS::CloudFormation::CustomResource
    Condition: Enabled
    Version: 1.0
    Properties:
      ServiceToken: !GetAtt AsgProcessModifierFunction.Arn
      Action: SuspendProcesses
      AutoScalingGroupName: !Ref Asg
      ScalingProcesses:
      - HealthCheck