Setting up SQS as event source with serverless and cloudformation.

AWS recently announced SQS as an event source for lambda functions. This is now GA and looks like there is already a pr for it to to be soon implemened in serverless framework as well.

As soon as it was announced we had a use case for this implementation in a project that we built with serverless . So instead of waiting pr to be merged i decided to impletemented via cloudformation.

Below is the serverless.yml file with its entirety. Cloudformation creates a sqs and and EventSourceMapping for the function supervisor.

service: cd-evox

provider:
  name: aws
  runtime:  nodejs8.10
  iamRoleStatements:
    - Effect: 'Allow'
      Action:
        - "lambda:InvokeFunction"
        - "lambda:InvokeAsync"
        - "sqs:ReceiveMessage"
        - "sqs:DeleteMessage"
        - "sqs:GetQueueAttributes"
      Resource: "*"




functions:
  supervisor:
    handler: lambdas.supervisor


# Create Sqs Queue
resources:
  Resources:
    mapping:
      Type: AWS::Lambda::EventSourceMapping
      Properties:
        EventSourceArn:
          Fn::GetAtt:
            - CdEvoxQueue
            - Arn
        FunctionName:
          Fn::GetAtt:
            - SupervisorLambdaFunction
            - Arn
    CdEvoxQueue:
      Type: AWS::SQS::Queue
      Properties:
        QueueName: cd_evox_${opt:stage}
        MessageRetentionPeriod: '1209600'
        VisibilityTimeout: '60'

Maximum batch size currently supported is between 1-10 so if you define a batch size higher than 10 you will receive the error message: An error occurred: mapping - Maximum batch size must be between 1 and 10 inclusive (Service: AWSLambda; Status Code: 400; Error Code: InvalidParameterValueException; Request ID: a03c1359-7cd5-11e8-8e95-8fcb11ee2f63).