template.yaml

AWSTemplateFormatVersion: '2010-09-09'
Transform: AWS::Serverless-2016-10-31
Description: >
  auto-cloudwatch-alarm

  Auto Create/Delete CloudWatch Alarms POC

# More info about Globals: /~https://github.com/awslabs/serverless-application-model/blob/master/docs/globals.rst
Globals:
  Function:
    Timeout: 30
    MemorySize: 128

Resources:
  AutoAlarmFunction:
    Type: AWS::Serverless::Function # More info about Function Resource: /~https://github.com/awslabs/serverless-application-model/blob/master/versions/2016-10-31.md#awsserverlessfunction
    Properties:
      FunctionName: auto_cloudwatch_function
      CodeUri: auto_cloudwatch_alarm/
      Handler: app.lambda_handler
      Runtime: python3.9
      Architectures:
        - x86_64
      Environment:
        Variables:
          TARGET_REGION: ap-northeast-1
      Policies:
        - CloudWatchFullAccess
        - AmazonEC2ReadOnlyAccess
      Layers:
        - !Ref libs
      Events:
        Trigger:
          Type: CloudWatchEvent 
          Properties:
            Pattern:
              source:
                - aws.ec2
              detail-type:
                - EC2 Instance State-change Notification                
              detail:
                state:
                  - running
                  - terminated

  UpdateAlarmFunction:
    Type: AWS::Serverless::Function # More info about Function Resource: /~https://github.com/awslabs/serverless-application-model/blob/master/versions/2016-10-31.md#awsserverlessfunction
    Properties:
      FunctionName: update_cloudwatch_function
      CodeUri: auto_cloudwatch_alarm/
      Handler: update-alarm.lambda_handler
      Runtime: python3.9
      Architectures:
        - x86_64
      Environment:
        Variables:
          TARGET_REGION: ap-northeast-1
      Policies:
        - CloudWatchFullAccess
        - AmazonEC2ReadOnlyAccess
      Layers:
        - !Ref libs

  libs:
    Type: AWS::Serverless::LayerVersion
    Properties:
      LayerName: auto-cloudwatch-layer
      Description: Lambda layer with libs like boto3 and yaml
      ContentUri: ./libs
      CompatibleRuntimes:
        - python3.9
    Metadata:
      BuildMethod: python3.9


Outputs:
  # ServerlessRestApi is an implicit API created out of Events key under Serverless::Function
  # Find out more about other implicit resources you can reference within SAM
  # /~https://github.com/awslabs/serverless-application-model/blob/master/docs/internals/generated_resources.rst#api
  AutoAlarmFunction:
    Description: "AutoAlarmFunction ARN"
    Value: !GetAtt AutoAlarmFunction.Arn