Trying to create AWS Elasticsearch cluster using serverless. Ended up with Status Code: 409; Error Code: InvalidTypeException

Question

Following is a snippet from my serverless.yml file to create elasticsearch domain. If I comment AccessPolicies section, elasticsearch domain got created but it fails when I un-comment it. I want to give access to the resources of my AWS account to access elasticsearch service. Not sure what is wrong. When I explore in stackoverflow or google, I hit some results but are related to terraform. Note: I use serverless-pseudo-parameters to refer to variables in serverless.yml.

EventsElasticsearchDomain:
  Type: AWS::Elasticsearch::Domain
  Properties:
    ElasticsearchVersion: 7.4
    DomainName: testevents
    ElasticsearchClusterConfig:
      InstanceCount: 1
      InstanceType: m5.large.elasticsearch
      ZoneAwarenessEnabled: false
    EBSOptions: # its expected when we use m4 or m4 InstanceType
      EBSEnabled: true
      VolumeSize: 10
      VolumeType: gp2
    AccessPolicies:
      Version: 2012-10-17
      Statement:
        - Effect: Allow
          Principal:
            AWS: '#{AWS::AccountId}'
          Action: 'es:ESHttp*'
          Resource:
            - arn:aws:es:#{AWS::Region}:#{AWS::AccountId}:domain/testevents/*

Error:

An error occurred: EventsElasticsearchDomain - Error setting policy:
  [{"Version":"2012-10-17T00:00:00.000Z","Statement":[{"Action":"es:ESHttp*","Resource":["arn:aws:es:REGION:ACCNUMBER:domain/testevents/*"],"Effect":"Allow","Principal":{"AWS":"ACCNUMBER"}}]}] 
(Service: AWSElasticsearch; 
Status Code: 409; Error Code: InvalidTypeException; Request ID: xxxxxxxxxxx).

Answer 1

Well, found the culprit. Its me giving the version as date object rather than a string. Changing the Version: 2012-10-17 to Version: '2012-10-17' fixed the issue.

We can notice it in the error message: "Version":"2012-10-17T00:00:00.000Z". It shows value of Version as date string, not the string that I've sent.

Answer 2

You for got about !Sub and $ in your policy:

Resource:
   - !Sub "arn:aws:es:${AWS::Region}:${AWS::AccountId}:domain/testevents/*"

The same for

    Principal:
      AWS: !Sub "${AWS::AccountId}"