Configure a Lambda Warmer using AWS CDK

Question

It's possible to configure a Lambda warmer function using AWS SAM.

Resources:
  # ...
  Web:
    Type: AWS::Serverless::Function # https://github.com/awslabs/serverless-application-model/blob/master/versions/2016-10-31.md#awsserverlessfunction
    Properties:
      CodeUri: web/
      Handler: lambda.handler
      Runtime: nodejs10.x
      FunctionName: !Sub myproject-${Stage}-web
      Events:
        Root:
          Type: Api # https://github.com/awslabs/serverless-application-model/blob/master/versions/2016-10-31.md#api
          Properties:
            Path: /
            Method: ANY
            RestApiId: !Ref WebRestApi
        RootProxy:
          Type: Api # https://github.com/awslabs/serverless-application-model/blob/master/versions/2016-10-31.md#api
          Properties:
            Path: /{proxy+}
            Method: ANY
            RestApiId: !Ref WebRestApi
        WarmingSchedule:
          Type: Schedule
          Properties:
            Schedule: rate(5 minutes)
            Input: '{ "warmer":true,"concurrency":3 }'
      MemorySize: 512
      Policies:
        - AWSLambdaRole

How would one create a warmer using the AWS CDK? Is there an "out of the box" solution or would a custom lambda function using Schedule.cron be necessary?

Answer 1

You would need a cron job in Cloudwatch which triggers your lambda to keep it warm or you use the serverless plugin:

https://serverless.com/blog/keep-your-lambdas-warm/